# Galactic O-type stars in LAMOST data

Guang-Wei Li Key laboratory of Space Astronomy and Technology, National
Astronomical Observatories, Chinese Academy of Sciences, Beijing 100101, China

(Received November. 21, 2020; Revised January. 28, 2021)

###### Abstract

This paper reports 209 O-type stars found with LAMOST. All 135 new O-type
stars discovered so far with LAMOST so far are given. Among them, 94 stars are
firstly presented in this sample. There are 1 Iafpe star, 5 Onfp stars, 12 Oe
stars, 1 Ofc stars, 3 ON stars, 16 double-lined spectroscopic binaries, and 33
single-lined spectroscopic binaries. All O-type stars are determined based on
LAMOST low-resolution spectra ($R\sim 1,800$), with their LAMOST median-
resolution spectra ($R\sim 7,500$) as supplements.

binaries: general – stars: early-type – stars: emission-line, Be – stars

††journal: ApJS††facilities: LAMOST

##  1 Introduction

O-type stars are very rare and short-lived, but they play important roles in
many astronomical fields. They illuminate the galaxy where they live. They
produced tremendous amounts of ionizing photons that punctured the neutral gas
and made the universe transparent in the Epoch of Reionization(Haiman & Loeb,
1997; Loeb & Barkana, 2001). Their stellar winds and powerful explosions when
they die are drivers of gas in galaxies (Rogers & Pittard, 2013), while their
ejecta can enrich surrounding gas where new stars are born. They are thought
to be the progenitors of many core-collapse supernovae (CCSNe), and long
gamma-ray bursts (LGRBs) (Woosley & Bloom, 2006; Langer, 2012), and also
responsible for some gravitational-wave events (de Mink & Mandel, 2016).
Besides, massive stars are good tools to study the structure of the Galactic
plane (Xu et al., 2018; Chen et al., 2019; Cheng et al., 2019).

Sana et al. (2012) presented that most O-type are born in binary systems, and
about three-quarters of O-type stars would undergo interactions. Thus,
multiple observations for these O-type stars from different epochs are
necessary to understand their interaction processes and nature. As a result,
the compilation of Galactic massive stars is a fundamental work. Reed (2003)
gave a widely used catalog of OB stars based on optical photometry. Later,
Maíz-Apellániz et al. (2004) gave a catalog of 378 O-type stars based on
optical spectroscopy. Then, the Galactic O-Star Spectroscopic Survey (GOSSS)
(Maíz Apellániz et al., 2011) presented 594 O-type stars by a uniform spectral
classification criteria (Sota et al., 2011, 2014; Maíz Apellániz et al.,
2016). Recently, Liu et al. (2019) presented the largest OB catalog from
Guoshoujing Telescope (the Large Sky Area Multi-Object Fiber Spectroscopic
Telescope, LAMOST) database, and Roman-Lopes & Roman-Lopes (2019) also gave a
catalog of 27 new O-type stars based on the LAMOST database. Beyond the
Galaxy, 213 O-type stars in 30 Doradus were given by Walborn et al. (2014).

In this paper, I compile 209 O-type stars found in the LAMOST database until
the end of 2018.

##  2 Data

I used the method given in Li & Howarth (2020) to select O-type stars in the
LAMOST low-resolution spectral data ($R\sim 1,800$) between 2011 and 2018, and
LAMOST medium-resolution spectra ($R\sim 7,500$) are also used, if any.
Information about LAMOST low- and medium-resolution spectra can be referred to
Wang et al. (1996), Su & Cui (2004), Cui et al. (2012), Luo et al. (2012),
Zhao et al. (2012) and Liu et al. (2020). Each star is assigned with the name
of ”LAMOST-O xxx”, where ”xxx” is a number ascending with the star’s galactic
longitude. All O-type stars found in LAMOST databases, with their names
recommended by Simbad, sky positions, and spectral classifications, are
tabulated in Table 1. The LAMOST low- and medium-resolution spectra shown in
this paper are provided in the China-VO PaperData repository:
doi:10.12149/101049

##  3 Spectral classification method

In this section, a brief introduction to the spectral classification scheme is
given. The detailed spectral classification criteria for O-type stars are from
Sota et al. (2011, 2014) and Maíz Apellániz et al. (2016), while spectral type
and luminosity sequences are shown in Figures 3-11 in Sota et al. (2011).

  1. 1.

The spectral type is primarily based on the ratio of He II $\lambda$4542/He I
$\lambda$4471\. The later the spectral type, the smaller the ratio, and is
$\sim$ 1 at O7. For types equal to or later than O8, He II $\lambda$4542/He I
$\lambda$4388 and He I $\lambda$4388/He I $\lambda$4144 become very useful to
determine spectral type. At O9, both are $\sim$ 1\. Moreover, the ratio of Si
III $\lambda$4552/He II $\lambda$4542 becomes useful for determining spectral
types later than O9, and $\sim$1, at O9.7 (see Table 3 in Sota et al. (2014)).
A spectral type sequence of LAMOST O dwarfs are shown in Figure 1.

  2. 2.

For stars earlier than O9, the luminosity classification is based on the
features of He II $\lambda$4686 and N III $\lambda$4634-4640-4642, which
define the ’Of’ phenomenon: ((f)) means weak emission of the N III line, while
there is strong absorption of the He II line; (f) means medium N III emission,
while the He II absorption is weak; f means both lines are in strong emission.
The stronger the Of effect, the higher the luminosity (see Table 2 in Sota et
al. (2014)). A luminosity sequence for O-type stars earlier than O9 is shown
by the top five spectra in Figure. 2.

  3. 3.

For stars equal to or less than O9, the luminosity classification is based on
the ratios of He II $\lambda$4686/He I $\lambda$4713 and He I $\lambda$4026/Si
IV $\lambda$4089\. The the lower the ratios, the higher the luminosity (see
Table 6 in Sota et al. (2011)). A luminosity sequence for O9 is shown by the
bottom three spectra in Figure. 2.

  4. 4.

The suffix $z$ is assigned to stars with the ratio of $\mathbf{EW}$(He II
$\lambda$4686) / Max[$\mathbf{EW}$(He II $\lambda$4686), $\mathbf{EW}$(He II
$\lambda$4686)] $>$ 1.1, which are supposed to be very near the zero-age main
sequence (Sabín-Sanjulián et al., 2014; Arias et al., 2016).

  5. 5.

As in Sota et al. (2011), (n), n and nn are used to indicate the rotational
broadening, with roughly projected rotational velocities of 200 km s-1, 300 km
s-1, and 400 km s-1, respectively.

Figure 1: A spectral type sequence of LAMOST O dwarfs. Figure 2: Luminosity
sequences of LAMOST O-type stars. The top five spectra are for earlier stars,
while the bottom three spectra for later stars.

The MK spectral classification is to compare the spectrum under study to
standard spectra. It is impossible for these standard spectra to cover all
kinds of spectra. Thus, compromises are needed. Moreover, the signal-to-noise
ratio, rotational effect, stellar wind, metallicity, and even spectral
resolution influence the classification. Thus, the spectral classification is
something of an art.

So far, there are still no widely accepted quantitative spectral
classification criteria. Martins (2018) gave a quantitative spectral
classification based on the equivalent widths (EWs) of some lines, but cannot
assign an exact spectral type to a star with only these quantities. Moreover,
both the quality and resolution of LAMOST spectra are low. As a result, the
classic MK spectral classification method is used. Specifically, all O-type
stars in this paper are assigned spectral types by comparing with standard
O-type stars in Table 2 in Maíz Apellániz et al. (2016).

##  4 Result

###  4.1 Iafpe

O Iafpe stars are Of stars, with He I $\lambda$4471 showing P Cygni profiles
(Sota et al., 2014).

_LAMOST-O 027 = Schulte 9_. This star is also in GOSSS (Sota et al., 2014),
with a spectral type of O4.5 If. By comparing two spectra given by LAMOST (see
Figure 3) and GOSSS, respectively, this star is an SB1 ($\Delta V\sim 44$ km
s-1) and also shows variations of the emission lines, but its spectral type is
unchanged. In high-quality spectra, it is an SB2 (Nazé et al., 2012).

_LAMOST-O 076 = LS I +62 14_. In Skiff (2014), its spectral type is B0 or OBe.
Thus, it may be a new O-type star. Its spectrum is very similar to that of
LAMOST-O 027 in Figure 3: He II $\lambda$4686 and N III $\lambda$4634-40-42
are both in strong emissions. However, their He I $\lambda$4471 and H $\beta$
are different.

In the spectrum of LAMOST-O 076, the He I $\lambda$4471 absorption is very
sharp, which may be infilled by emission produced by the material in the
stellar wind. Moreover, there may be emission in the blue wings of He I
$\lambda$4471 and H $\beta$, though weak, so He I $\lambda$4471 and H $\beta$
may be P Cygni profiles. As a result, LAMOST-O 076 is an O5: Iafpe candidate.

Figure 3: Spectra of LAMOST-O 027 and 076.

###  4.2 Onfp

The Onfp category consists of fast-rotating Of stars that have absorption
reversals in its He II $\lambda$4686 emissions (Sota et al., 2014). All LAMOST
spectra of Onfp stars are shown in Figure 4.

_LAMOST-O 001 = HD 172 175_. This star is also in GOSSS. By comparing two
spectra given by LAMOST and GOSSS (Sota et al., 2011), respectively, the ratio
of He II $\lambda$4200/He I $+$ II $\lambda$4026 is $\sim$ 1 in the LAMOST
spectrum, a little higher than that in the GOSSS spectrum, which results in a
little earlier spectral type in the LAMOST spectrum, O6 I(n)fp.

_LAMOST-O 036 = UCAC4 669-086327_. In Roman-Lopes & Roman-Lopes (2019), this
star is O4 IV(f). In the LAMOST spectrum, its C III $\lambda$4647-50-51
emission is also strong enough to be assigned to a suffix of (c). Moreover,
its He II $\lambda$4686 has a weak emission wing. As a result, it is an O4
IV(fc)p.

_LAMOST-O 094 = HD 14 442_. Comparing two spectra given by LAMOST and GOSSS
(Sota et al., 2011), it is an SB1 star ($\Delta V\sim 72$ km s-1), with a
variable He II $\lambda$4686 profile.

_LAMOST-O 121 = LAMOST J040643.69+542347.8_. This star is the fastest rotator
in the Galaxy with a $v_{e}\sin i\sim 540$ km s-1. It is also a runaway, which
implies binary origin. For detailed information, refer to Li (2020).

_LAMOST-O 205 = HD 292 419_. It is a B-type star in Reed (2003), but its
LAMOST spectrum is O6 Iafp.

Figure 4: Spectra of Onfp stars (LAMOST-O 001, 036, 094, 121, and 205) and the
Ofc star (LAMOST-O 043).

###  4.3 Ofc

The Ofc category consists of normal spectra with the emission intensity of C
III $\lambda$4650 similar to that of N III $\lambda$4634 (Sota et al., 2014),
and peaks at O5 for all luminosity classes. There is only one Ofc star in
LAMOST data as shown in Figure 4.

_LAMOST-O 043 = LS III +56 109_. This star is an SB2 in Maíz Apellániz et al.
(2016). Comparing its spectra from LAMOST and GOSSS, there is a $\Delta V$ of
$\sim 155$ km s-1.

###  4.4 Oe

The Oe category was defined by Conti & Leep (1974) and is thought to be the
hotter counterpart of the classic Be category (Rivinius et al., 2013). Until
2018, there were only 13 Oe stars in the Galaxy (Li et al., 2018). Here, I
present another 12 Oe-type stars found with LAMOST (see Figure 5). Among them,
LAMOST-O 013 = LS II +23 14, LAMOST-O 065 = EM* GGR 149, LAMOST-O 095 = V* KM
Cas, LAMOST-O 159 = RL 128, LAMOST-O 161 = HD 255 055, and LAMOST-O 206 = EM*
RJHA 83 = TYC 4801-17-1 had been discussed in Li et al. (2018).

_LAMOST-O 010 = TYC 5122-465-1_. This star has no spectral information in
Simbad, and thus may be a new O-type star. Its spectrum in Figure 5 shows it
is an O9 IIIn star, while emissions in the blue wings of its H$\alpha$ lines
in two LAMOST low-resolution spectra (see Figure 6) imply it may be an Oe
star.

_LAMOST-O 035 = RLP 1252_. In Roman-Lopes & Roman-Lopes (2019), its spectral
type is O8 III(f)e, but the LAMOST spectrum shows that He II $\lambda$4686 is
much stronger than He I $\lambda$4713, so it is a dwarf. Moreover, its N III
$\lambda$4634-40-42 is not easily recognized from noise. Thus, it is O8 Ve.

_LAMOST-O 038 = BD+53 2790_. This star is an X-binary (Ribó et al., 2006), but
Blay et al. (2006) suggested it is a peculiar single O-type star. Its
H$\alpha$ profile in Figure 6 indicates that it is an Oe shell-like star.
However, the ratio of He II $\lambda$4686/He I $\lambda$4713 indicates that
its luminosity is II, but its weak Si IV $\lambda$4089 and 4116 indicate a
lower luminosity. Thus its luminosity is unclear.

_LAMOST-O 047 = HD 240 197_. In Simbad, its spectral type is B5 (Cannon &
Pickering, 1993). Its H$\alpha$ and H$\beta$ profiles in the LAMOST spectrum
suggest it is an Oe star. Moreover, its C III lines have almost disappeared,
while the N III $\lambda$4634-40-42 absorption is very strong. The ratio of He
II $\lambda$4686/He I $\lambda$4713 indicates that its luminosity is II, but
its weak Si IV $\lambda$4089 and 4116 indicate it is a dwarf. Thus, its
luminosity is unclear. As a result, it is assigned ON9.7 (n)e.

This star may be a pole-on, rapidly rotating star. The rapid rotation induces
chemically homogeneous evolution, which can take C and H on the stellar
surface into the core, while bringing the N produced by the CNO-burning cycle
in the core back to the surface (Maeder & Meynet, 2000). The rapid rotation
also lifts the material around the equator lifted to form a circumstellar
disk, where emission lines are produced (Rivinius et al., 2013). The strong Mg
II $\lambda$4481 also implies circumstellar material. As a result, we see an
Oe star with N enrichment, but without C.

_LAMOST-O 053 = HD 240 234_. In Simbad, its spectral type is B0 (Brodskaya,
1953), but the LAMOST spectrum clearly shows it is an O9.7 V(n)e star.

_LAMOST-O 065 = EM* GGR 149_. It was classified as O9.7 IVn in Li et al.
(2018). But by comparing the standard stars in Maíz Apellániz et al. (2016),
it is more like a dwarf. Moreover, it should be a slower rotator compared to
other rotation stars. As a result, it is assigned O9.7 V(n)e.

_LAMOST-O 100 = HD 14 645_. In Simbad, its spectral type is B0 IV:nn (Hiltner,
1956). According to the latest GOSSS criteria, it is an O9.7 star. For the
same reason as LAMOST-O 038, its luminosity is unclear. The H$\alpha$ profiles
in its two LAMOST medium-resolution spectra have variable emission wings (see
Figure 6), which suggest it is also an Oe star. As a result, it is O9.7 ne.

_LAMOST-O 159 = RL 128_. This star is a Kepler K2 star, with a period of 5.03
days (Buysschaert et al., 2015). Its H$\alpha$ emission is variable, and Ca II
triplet emission also appears sometimes (Li et al., 2018). It is very dim,
$V=15.11$ mag, but near, $\varpi=0.1752\pm 0.0316$ mas (Gaia Collaboration,
2020), that is $\sim$ 5.7 kpc. If there is no extinction, the absolute
magnitude $M_{V}\sim 1.33$ mag, which means that it is an sdO. In fact, it is
very blue ($U-B=-0.9$ mag) (Mermilliod, 1987), which implies extinction should
be $\ll 6$ mag (Walborn, 2002). As a result, this star may be a binary, and
the primary is a sdO, which is accreting the material from the secondary.
Because of the low qualitiy of LAMOST spectra, the GOSSS spectral type with a
suffix ’e’ is adopted: O4.5 V((c))ze.

_LAMOST-O 161 = HD 255 055_. Its spectral type was O9.5 IIIe in Li et al.
(2018), but here it is revised to O9.2 IVe.

Figure 5: Spectra of Oe stars (LAMOST-O 010, 013, 035, 038, 047, 053, 065,
095, 100, 159, 161, and 206). Figure 6: LAMOST median-resolution spectra of Oe
stars (LAMOST-O 010, 038 and 100) and the SB2 LAMOST-O 135. Two spectra of a
star from different epochs are shown in black and red spectra, respectively.

###  4.5 ON

The O-type stars with N III $\lambda$4641/42 absorption stronger than C III
$\lambda$4650/51 absorption are classified as ON stars. Their enriched N may
be produced by the nucleosynthesis , and transported to the surface by the
rotationally induced mixing (Li & Howarth, 2020). LAMOST ON stars are shown in
Figure 7.

LAMOST-O 074 = LS I +61 28 and LAMOST-O 085 = HD 236 672 had been discussed in
Li & Howarth (2020), while LAMOST-O 047 = HD 240 197 was presented in
Subsection 4.4.

Figure 7: Spectra of ON stars: LAMOST-O 047, 074, and 085.

###  4.6 Double-lined Spectroscopic Binaries (SB2)

LAMOST SB2 stars are shown in Figure 8. Because of the low resolution and/or
quality of LAMOST spectra, the spectral types of the primary and secondary in
each binary may be not correctly determined.

_LAMOST-O 003 = TYC 5125-3040-1_. In Simbad, there is no spectral information
about this star. Thus, it may be a new SB2. The period is 4.3326 days (Shappee
et al., 2014).

_LAMOST-O 039 = V* AW Lac_. In Simbad, it is a $\beta$ Lyrae type eclipsing
system, with a period of 1.14285456 days (Jiang et al., 1983). In Skiff
(2014), its spectral type is OB or B type. Its LAMOST spectrum is an SB2.

_LAMOST-O 041 = BD+54 2789_. In Simbad, it is a double or multiple system. In
Skiff (2014), its spectral type is OB. There are too many stars crowded around
BD+54 2789, so the LAMOST spectrum may be contaminated.

_LAMOST-O 044 = LS III +57 99_. In Skiff (2014), its spectral type is OB-. In
Shappee et al. (2014), it is a binary with a period of 1.8432649 days.

_LAMOST-O 056_. In Skiff (2014), its spectral type is B. Its LAMOST spectrum
is an SB2.

_LAMOST-O 060_. In Skiff (2014), its spectral type is O8.5 Ve (Chini & Wink,
1984) or O9 V (Russeil et al., 2007). It is also suggested to be an eclipsing
binary with a period of 1.1409 days (Shappee et al., 2014).

_LAMOST-O 072 = V* QQ Cas_. In Skiff (2014), its spectral type is OB or B
type. In Simbad, it is a $\beta$ Lyrae type eclipsing system, with a period of
2.142030 days (Kukarkin, 1957).

_LAMOST-O 087 = Hilt 233_. This star has been resolved by GOSSS as an SB2
(Maíz Apellániz et al., 2016), which is adopted in this paper.

_LAMOST-O 104 = LS I +62 223_. In Skiff (2014), its spectral type is OB+. The
LAMOST spectrum is an O binary.

_LAMOST-O 108 = LS I +62 227_. In Skiff (2014), its spectral type is OB,
OB$+$e, or B2. The LAMOST spectrum is an O binary.

_LAMOST-O 109_. This star is an SB2, which will be discussed in a future paper
and not shown in Figure 8.

_LAMOST-O 135 = LS V +48 12_. In Roman-Lopes & Roman-Lopes (2019), its
spectral type is O8.5 III(f). But there is no N III $\lambda$4634-40-42
emission. Its LAMOST median-resolution spectra show it is an SB2 in Figure 6.
If two stars in the binary have a similar mass, then their spectral type
should be around O9.5.

_LAMOST-O 141 = LS V +38 12_. This star is assigned a spectral type of
O7V((f))+B0III-V by Maíz Apellániz et al. (2016). In Figure 8, the He II
$\lambda$4542 is slightly stronger than He I $\lambda$4471 for the primary, so
it should be O6.5 V((f))+B0 III-V.

_LAMOST-O 144 = LS V +38 15_. In Roman-Lopes & Roman-Lopes (2019), its
spectral type is O8.5 IV(n), but the asymmetries of He I $\lambda$4388, 4471,
4922, and He II $\lambda$4686 suggest it is an SB2.

_LAMOST-O 162 = HD 255 312_. It was observed by the Kepler telescope in the K2
mission with a quasi-period of 0.734701 days (Armstrong et al., 2015).
However, Shappee et al. (2014) suggested it is an eclipsing binary with a
period of 1.46976 days.

_LAMOST-O 185 = HD 48 099_. The LAMOST spectrum is 15.73” away from HD 48 099.
This star is also in GOSSS (Sota et al., 2014). The signal-to-noise ratio of
the LAMOST spectrum is low, but the spectra of LAMOST and GOSSS seem well
consistent with each other. Thus, the GOSSS spectral type O5 V((f))z + O9: V
is adopted.

Figure 8: Spectra of SB2 stars ( LAMOST-O 003, 007, 039, 041, 044, 056, 059,
060, 072, 087, 104, 108, 135, 141, 144, 162, and 185).

###  4.7 Single-lined Spectroscopic Binaries (SB1)

SB1 stars are shown in Figure 9. Each star was observed by LAMOST for at least
two times and shows an obvious shift in wavelength between its spectra from
different epochs. LAMOST-O 023, 073, and 146 are determined to be SB1 stars
from their medium-resolution spectra from different epochs, while others are
determined from low-resolution spectra.

_LAMOST-O 023 = TYC 3156-1881-1_. In Berlanas et al. (2018), its spectral type
is O8 IIIz. The LAMOST spectrum is O7 Vz. According to its medium-resolution
spectra, it is an SB1, with $\Delta V\sim 75$ km s-1.

_LAMOST-O 073 = LS I +62 4_. In Skiff (2014), its spectral type is OB-. Its
LAMOST spectral type is O9.5 V. According to its medium-resolution spectra, it
is an SB1, with $\Delta V\sim 43$ km s-1.

_LAMOST-O 081 = LS I +62 25_. In Skiff (2014), its spectral type is OB. Its
LAMOST spectral type is O9.7 III, with $\Delta V\sim 168$ km s-1.

_LAMOST-O 084 = HD 240 464_. Martin (1972) classified this star as O9 V. Its
LAMOST spectral type is O9.5 V, with $\Delta V\sim 90$ km s-1.

_LAMOST-O 097 = BD+60 498_. This star has a spectral type of O9.7 II-III in
Sota et al. (2011), but by comparing spectra from LAMOST and GOSSS, its He I
$\lambda$4713 in the LAMOST spectrum is slightly weaker than that in the GOSSS
spectrum. Thus, it is classified as O9.7 IV. Besides, there is an obvious
wavelength shift between two spectra ($\Delta V\sim 96$ km s-1), which
suggests it is an SB1.

_LAMOST-O 105 = BD+60 544_. In Simbad, this star is a double or multiple
system, but without reference. In Rydstrom (1978), its spectral type is OB:.
Its LAMOST spectral type is O9.7 III, with $\Delta V\sim 22$ km s-1.

_LAMOST-O 113 = BD+60 594_. In Rydstrom (1978), its spectral type is O9 V. Its
LAMOST spectral type is O8.5 Vn, with $\Delta V\sim 60$ km s-1.

_LAMOST-O 130 = TYC 3340-2437-1_. In Liu et al. (2019), its spectral type is
B. Its LAMOST spectral type is O9.7 III, with $\Delta V\sim 60$ km s-1.

_LAMOST-O 131 = LS V +48 9_. In Roman-Lopes & Roman-Lopes (2019), its spectral
type is O9.7 IVn. Its weak He II $\lambda$4686 indicates a high luminosity,
but its weak Si IV $\lambda$4089 and 4116 imply a low one. Thus, its
luminosity is unclear. As a result, it is assigned O9.7 n. Its He II line
profiles show obvious variabilities or shifts, which imply it is an SB1.

_LAMOST-O 139 = HD 277 878_. In Roman-Lopes & Roman-Lopes (2019), its spectral
type is also O7 V((f))z. Moreover, there is a $\Delta V\sim 35$ km s-1 between
LAMOST spectra.

_LAMOST-O 146 = LS V +34 21_. In Roman-Lopes & Roman-Lopes (2019), its
spectral type is also O9 IV. According to its medium-resolution spectra, it is
an SB1, with $\Delta V\sim 18$ km s-1.

_LAMOST-O 155 = LS V +29 22_. In Skiff (2014), its spectral type is OB. Its
LAMOST spectral type is O9.7, with an unclear luminosity. LAMOST spectra also
have a $\Delta V\sim 52$ km s-1.

_LAMOST-O 199 = TYC 147-1646-1_. In Moffat et al. (1979), its spectral type is
B0 III. For a similar reason to LAMOST-O 131, its luminosity is unclear.
Though $\Delta V\sim 18$ km s-1 is slightly low, it should be an SB1 from
direct comparison of two high signal-to-noise spectra.

Figure 9: Spectra of SB1 stars ( LAMOST-O 023, 073, 081, 084, 097, 105, 113,
130, 131, 139, 146, 155, and 199).

###  4.8 Vz

OVz stars are on or very near the zero-age main-sequence O (Walborn, 2009).
Thus, they are among the youngest massive stars (Arias et al., 2016). In
Figure 10, 14 OVz stars in LAMOST data are shown. LMOST-O 023 and 139 are SB1
and have been presented in Subsection 4.7.

_LAMOST-O 016 = HD 338 916_. This star is also in GOSSS data (Maíz Apellániz
et al., 2016), with a spectral type of O7.5 Vz. There is no radial velocity
variation between LAMOST and GOSSS spectra, but He I $\lambda$4471 and He II
$\lambda$4542 in the LAMOST spectrum are a little stronger.

_LAMOST-O 028 = GSC 03161-01264_ and _LAMOST-O 032 = GSC 03161-01086_. These
two stars are O6.5 V and O7 V, respectively, in Comerón & Pasquali (2012).
However, their He II $\lambda$4686 in LAMOST spectra are strong enough to be
Oz. Thus, they are O6.5 Vz and O7 Vz, respectively.

_LAMOST-O 034 = Schulte 29_. Its GOSSS spectral type is O7.5 V(n)((f))z (Maíz
Apellániz et al., 2016). But its He I $\lambda$4471 in LAMOST spectrum is a
little weaker than that in the GOSSS spectrum, thus it is O7 V(n)((f))z. It is
an SB1 (Kobulnicky et al., 2014), but its LAMOST and GOSSS spectra do not show
obvious radial velocity variation. The reason may be that the semiamplitude of
the radial velocity curve of the primary, 17.5 km s-1, is too low to be
detected.

_LAMOST-O 062 = LS III +58 86_. This star was categorized as B2 in Brodskaya
(1953). Its LAMOST spectral type is O7 V(n)z.

_LAMOST-O 064 = LS I +60 9_. It is a B-type star, without reference in Simbad.
Its LAMOST spectral type is O7 Vn((f))z.

_LAMOST-O 068 = LS I +60 10_. In Brodskaya (1953), it is B2, but its LAMOST
spectral type is O7.5 Vz.

_LAMOST-O 088 = LS I +61 266_. It is a B-type star, without a reference in
Simbad. LAMOST spectral type is O6 Vz.

_LAMOST-O 092 = BD+61 411_. The spectral type is O6.5 V((f))z in Maíz
Apellániz et al. (2016), but the ratio of He II $\lambda$4542/He I
$\lambda$4471 in the LAMOST spectrum is slightly smaller than that in the
GOSSS spectrum, thus the LAMOST spectral classification is O7 V((f))z.
Moreover, there is a $\Delta V\sim 55$ km s-1 between LAMOST and GOSSS
spectra. Thus, it is an SB1.

_LAMOST-O 099 = BD+60 501_. There is a $\Delta V\sim 60$ km s-1 between LAMOST
and GOSSS spectra (Sota et al., 2011). Thus, it is an SB1.

_LAMOST-O 101 = BD+56 594_. In Rydstrom (1978), its spectral type is OB. Its
LAMOST spectral type is O7.5 Vz.

_LAMOST-O 124 = TYC 3339-851-1_. This star is O5 V((f)) in Roman-Lopes &
Roman-Lopes (2019), but the ratio of He II $\lambda$4542/He I $\lambda$4471 is
not that large. Moreover, its He II $\lambda$4686 is stronger than He II
$\lambda$4542 and He I $\lambda$4471, but N III $\lambda$4634-40-42 cannot be
undoubtedly identified. Thus, it is assigned as O6 Vz.

_LAMOST-O 149 = LS V +33 15_. This star is also in Maíz Apellániz et al.
(2016) with a spectral type of O7 V(n)z. But both He II $\lambda$4200/He I +
II $\lambda$4026 and He II $\lambda$4542/He I $\lambda$4471 are higher in
LAMOST spectrum, which suggests its spectral type should be O5.5.
Surprisingly, the strong absorption line C III $\lambda$4647/50/51 in the
GOSSS spectrum becomes emission in the LAMOST spectrum, while N III
$\lambda$4636/40/42 is also in emission in the LAMOST spectrum. There is a
wavelength shift between the GOSSS and LAMOST spectra ($\Delta V\sim 20$ km
s-1), and the H$\alpha$ line also shows a variation between two LAMOST
spectra. Thus, it should be an SB1, which may be responsible for the spectral
variation.

_LAMOST-O 150 = HD 242 926_. It is a spectral classification standard star of
O7 Vz (Maíz Apellániz et al., 2016). But there are still line variabilities
between LAMOST and GOSSS spectra. Specially, He II $\lambda$4686 in the LAMOST
spectrum is slightly weaker than that in the GOSSS spectrum.

_LAMOST-O 172 = TYC 1323-1592-1_. It is O7.5 V((f)) in Roman-Lopes & Roman-
Lopes (2019), but it should be O8.5 Vz.

_LAMOST-O 201 = Cl* Dolidze 25 MV 17_. In Negueruela et al. (2015), its
spectral type is also O7 Vz.

Figure 10: Spectra of Vz stars: LAMOST-O 016, 028, 032, 034, 062, 064, 068,
088, 092, 099, 101, 124, 149, 150, 172, and 201.

###  4.9 Normal stars

The following 13 stars are shown in Figure 11.

In Simbad, there is no spectral information about _LAMOST-O 006_ , _LAMOST-O
008 = TYC 5121-769-1_ , _LAMOST-O 015_ , and _LAMOST-O 017_. Thus, these four
stars may be new O-type stars.

_LAMOST-O 002 = TYC 5125-2083-1_. Its spectral type is B0 in Roslund (1963).
Its LAMOST spectrum is O9 II.

_LAMOST-O 004 = HD 173 820_. Its spectral type is B0.5 Ia/ab in Houk & Swift
(1999). Its LAMOST spectrum is O8.5 V.

_LAMOST-O 005 = BD-05 4769_. Its spectral type is O7 III in Bisiacchi et al.
(1982). Its LAMOST spectrum is O7.5 III((f)).

_LAMOST-O 007 = LS IV -04 20_. In Skiff (2014), its spectral type is OB or B2
Ib. Its LAMOST spectrum is an O 9.7 II-IIIn.

_LAMOST-O 009 = BD-04 4593_. Its spectral type is O9.5 Ia in Vijapurkar &
Drilling (1993). Its LAMOST spectrum is O9.7 II.

_LAMOST-O 011 = ALS 19303_. Its spectral type is B1 II in Forbes (1989). Its
LAMOST spectrum is roughly O7 V.

_LAMOST-O 012 = TYC 1036-450-1_. This star has unclear luminosity (Maíz
Apellániz et al., 2016). However, there is an obvious wavelength shift between
the LAMOST and GOSSS spectra ($\Delta V\sim 78$ km s-1). Thus, it is an SB1.

_LAMOST-O 014 = HD 345 475_. Its spectral type is B0 in Popper (1950). Its
LAMOST spectrum is roughly O9.7 II.

_LAMOST-O 018 = [NH52] 74_. Its spectral type is also O9.7 IV in Roman-Lopes &
Roman-Lopes (2019).

Figure 11: Spectra of LAMOST-O 002, 004, 005, 006,007, 008, 009, 011, 012,
014, 015, 017, and 018.

The following 13 stars are shown in Figure 12.

_LAMOST-O 019 = BD+37 3917_. Its spectral type is OB in Nassau & Harris
(1952). Its LAMOST spectrum is roughly O9.7 II.

_LAMOST-O 020 = HD 228 943_. Its spectral type is O9.7 III in Mathys (1989).
Its LAMOST spectrum is O9.7 III(n). Its radial velocity in the LAMOST spectrum
is more than 80 km s-1 lower than that given by Huang & Gies (2006), which
suggests this star may be an SB1.

_LAMOST-O 021 = TYC 3152-1390-1_. This star has no spectral information in
Simbad.

_LAMOST-O 022 = HD 194 094_. Its spectral type is O8.5 III in Mahy et al.
(2013). Its LAMOST spectrum is O9 III. Its radial velocities given by Evans
(1967), Mahy et al. (2013) and the LAMOST spectrum agrees well with each other
within 10 km s-1. Thus, it is likely a single star.

_LAMOST-O 024 = UCAC4 655-091969_. Its spectral type is also O8 III((f)) in
Roman-Lopes & Roman-Lopes (2019).

_LAMOST-O 025 = [CPR2002] A25_. Its spectrum is too noisy to be used for
classification. I adopt the spectral type O8 III given by Comerón & Pasquali
(2012).

_LAMOST-O 026 = [CPR2002] A26_. Its spectral type is O9 V in Comerón &
Pasquali (2012). But the ratio of He II $\lambda$4686/He I $\lambda$4713 in
the LAMOST spectrum suggests that its luminosity should be III.

_LAMOST-O 029 = Schulte 20_. Its spectral type is also O9 III in Comerón &
Pasquali (2012). LAMOST spectrum is O9.7 IV. In Kobulnicky et al. (2014), it
is an SB1.

_LAMOST-O 030 = Schulte 70_. Its spectral type is O9.5 IV(n) in Maíz Apellániz
et al. (2016), but its LAMOST spectrum is more like O9.5 III(n), because of
higher Si IV $\lambda$4089/He I $\lambda$4026\. In Kobulnicky et al. (2014),
it is an SB1, with a period of 245.1 days.

_LAMOST-O 031 = Schulte 17_. This star is also in Maíz Apellániz et al.
(2016). There is a wavelength shift between GOSSS and LAMOST spectra ($\Delta
V\sim 36$ km s-1). In Kobulnicky et al. (2014), it is an SB1.

_LAMOST-O 033 = BD+41 3804_. This star is also in Maíz Apellániz et al.
(2016).

_LAMOST-O 037 = 2MASS J20352227+4355304_. This star has been given in Roman-
Lopes & Roman-Lopes (2019).

_LAMOST-O 040 = HD 235 813_. Its spectral type is B0 III in Suad et al.
(2012). Its LAMOST spectrum is O9.7 II.

Figure 12: Spectra of LAMOST-O 019, 020, 021, 022, 024, 025, 026, 029, 030,
031, 033, 037, and 040

The following 13 stars are shown in Figure 13.

In Simbad, there is no spectral information about _LAMOST-O 046_ , _LAMOST-O
049_ , _LAMOST-O 050_ , _LAMOST-O 052_ , and _LAMOST-O 059_. Thus, these four
stars may be new O-type stars.

_LAMOST-O 042 = HD 235 989_. In Skiff (2014), its spectral type is B or OB.
Its LAMOST spectrum is O9.2 IIInn.

_LAMOST-O 045 = LS III +58 70_. Its spectral type is B0 V in Negueruela &
Marco (2003). LAMOST spectrum is O9.7 IV.

_LAMOST-O 048 = BD+58 2520_. Its spectral type is B2 in Brodskaya (1953). Its
LAMOST spectrum is O9.2 V.

_LAMOST-O 051 = Hilt 1202_. In Skiff (2014), its spectral type is B or OB. Its
LAMOST spectrum is O9.7 IIn.

_LAMOST-O 054 = LS III +59 58_. In Skiff (2014), its spectral type is B or OB.
Its LAMOST spectrum is O9.5 Vn.

_LAMOST-O 055 = LS III +59 63_. In Skiff (2014), its spectral type is B, OB,
or even A8. Its LAMOST spectrum is O7 III(n)(f).

_LAMOST-O 057 = TYC 4279-1192-1_. In Chini & Wink (1984), its spectral type is
also O9.5 V.

_LAMOST-O 058 = IRAS 23149+5938_. In Skiff (2014), its spectral type is F. Its
LAMOST spectrum is O9.7 III.

Figure 13: Spectra of LAMOST-O 042, 045, 046, 048, 049, 050, 051, 052, 054,
055, 057, 058, and 059.

The following 13 stars are shown in Figure 14.

_LAMOST-O 061 = LS I +59 5_. In Skiff (2014), its spectral type is B0 or OB.
Its LAMOST spectrum is O7.5 V((f)).

_LAMOST-O 063 = LS I +60 8_. In Cruz-González et al. (1974), its spectral type
is O9.5 V. Its LAMOST spectrum is O9.5 III.

_LAMOST-O 066_. In Russeil et al. (2007), its spectral type is O9 V. Its
LAMOST spectrum is O9.5 V.

_LAMOST-O 067_. In Russeil et al. (2007), its spectral type is O8 V. The ratio
of signal to noise of the LAMOST spectrum is very low, but it seems that the
ratio of He I $\lambda$4542/He I $\lambda$4388 $\sim$ 1, so it is assigned O9:
V.

_LAMOST-O 069 = LS I +59 11_. In Skiff (2014), its spectral type is B or OB.
Its LAMOST spectrum is O7.5 III((f)).

_LAMOST-O 070 = BD+58 2636_. In Skiff (2014), its spectral type is B or OB.
Its LAMOST spectrum is O9.2 III.

_LAMOST-O 071 = TYC 4280-103-1_. This star has no spectral information in
Simbad.

_LAMOST-O 075 = LS I +61 50_. In Skiff (2014), its spectral type is B2 or OB.
Its LAMOST spectrum is O7.5 Vn.

_LAMOST-O 077 = LS I +60 50_. In Hunter & Massey (1990), its spectral type is
also O9.5 III.

_LAMOST-O 078 = BD+60 2632_. In Skiff (2014), its spectral type is B or OB.
Its LAMOST spectrum is O9.5 IV.

_LAMOST-O 079 = HD 240 435_. The spectral type in Reed (2003) is B0.5.Its
LAMOST spectrum is O9.7 III.

_LAMOST-O 080 = BD+60 2635_. This star is also in Maíz Apellániz et al.
(2016). There is a wavelength shift between the GOSSS and LAMOST spectra
($\Delta V\sim 74$ km s-1). Thus, it is an SB1.

_LAMOST-O 082 = BD+62 2299_. In Skiff (2014), its spectral type is B or OB.
Its LAMOST spectrum is O8 II((f)).

Figure 14: Spectra of LAMOST-O 061, 063, 066, 067, 069, 070, 071, 075, 077,
078, 079, 080, and 082.

The following 13 stars are shown in Figure 15.

_LAMOST-O 083 = LS I +60 62_. In Skiff (2014), its spectral type is B or OB.
Its LAMOST spectrum is O8.5 V.

_LAMOST-O 086 = HD 13 022_. This star is also in Sota et al. (2011). There is
a wavelength shift between GOSSS and LAMOST spectra ($\Delta V\sim 69$ km
s-1). Thus, it is an SB1.

_LAMOST-O 089 = LS I +61 267_. In Hardorp et al. (1959), its spectral type is
OB. Its LAMOST spectrum is O7 V(n).

_LAMOST-O 090_. This star is not in Simbad, so it may be a new O-type star.

_LAMOST-O 091 = LS I +63 187_. In Skiff (2014), its spectral type is B or OB.
The ratio of He I $\lambda$4686/He I $\lambda$4713 suggests its luminosity is
II-III, but its Si IV$\lambda$4089 and 4116 are too weak to suggest a higher
luminosity, so it is assigned as O9.7 III.

_LAMOST-O 093 = BD+62 419_. In Skiff (2014), its spectral type is B or OB. Its
LAMOST spectrum is O9.7 III.

_LAMOST-O 096 = BD+62 424_. This star is also in Sota et al. (2011). There is
a wavelength shift between the GOSSS and LAMOST spectra ($\Delta V\sim 46$ km
s-1). Thus, it is an SB1. The ratio of He I + II $\lambda$4200 / He II
$\lambda$ 4026 $\sim$ 1, higher than that in the GOSSS spectrum. Besides,
limited by the low resolution of the LAMOST spectrum, its rotation is
indiscernible. Thus, its LAMOST spectrum is O6 V((f)).

_LAMOST-O 098 = BD+60 499_. This star is also in Sota et al. (2011). There is
a wavelength shift between the GOSSS and LAMOST spectra ($\Delta V\sim 54$ km
s-1). Thus, it is an SB1.

_LAMOST-O 102 = LS I +59 139_. In Hardorp et al. (1959), its spectral type is
OB. Its LAMOST spectrum is O9.7 IV.

_LAMOST-O 103 = TYC 3699-1537-1_. This star has no spectral information in
Simbad.

_LAMOST-O 106 = Lan 27_. In Margon & Downes (1981), its spectral type is late
B. Its LAMOST spectrum is O9.2 V.

_LAMOST-O 107_. This star has no spectral information in Simbad.

_LAMOST-O 110_. In Russeil et al. (2007), its spectral type is also O9.5 IV.

Figure 15: Spectra of LAMOST-O 083, 086, 089, 090, 091, 093, 096, 098, 102,
103, 106, 107, and 110.

The following 13 stars are shown in Figure 16.

_LAMOST-O 111 = 2MASS J02461010+6015576_. In Simbad, it is an infrared source
without spectral information. In the LAMOST spectrum, its He II $\lambda$4200
and 4686 are clearly seen, while He II $\lambda$4542 can be marginally seen,
so it is a late O-type star.

_LAMOST-O 112 = LS I +60 263_. In Skiff (2014), its spectral type is B or OB.
Its LAMOST spectrum is O7 III((f)).

_LAMOST-O 114_. This spectrum is 28”.34 away from HD 14 633. By comparing with
the GOSSS spectrum in Sota et al. (2011), the LAMOST spectrum is well
consistent with the GOSSS spectrum, but with low signal-to-noise ratio.

_LAMOST-O 115 = LS I +55 47_. In Roman-Lopes & Roman-Lopes (2019), its
spectral type is also O9.5 IV.

_LAMOST-O 116 = LS I +57 136_. In Russeil et al. (2007), its spectral type is
O9 V. Its LAMOST spectrum is O9.2 V.

_LAMOST-O 117 = BD+56 866_. In Negueruela & Marco (2003), its spectral type is
O9 V. Its LAMOST spectrum is O9.2 V(n).

_LAMOST-O 118_. This star has no spectral information in Simbad. Though the
signal-to-noise ratio is very low, its He II $\lambda$4542 is clearly seen.

_LAMOST-O 119 = LS V +55 12_. In Skiff (2014), its spectral type is B0 or OB.
Its LAMOST spectrum is O9.7 II.

_LAMOST-O 120 = TYC 3722-435-1_. There is no spectral information for this
star in Simbad.

_LAMOST-O 122 = BD+50 886_. This star is also in Maíz Apellániz et al. (2016).
There is a wavelength shift between GOSSS and LAMOST spectra ($\Delta V\sim
76$ km s-1). Thus, it may be an SB1. The N III $\lambda$4634/40/42 emission
cannot be identified anymore, but the C III $\lambda$4647/50/51 emission
emerges. Thus, it is O4 V((c)).

_LAMOST-O 123 = LS V +53 20_. In Roman-Lopes & Roman-Lopes (2019), its
spectral type is O9 V. By comparing with standard stars in GOSSS, its spectral
type is more like O9.2 V.

_LAMOST-O 125 = LS V +51 16_. In Roman-Lopes & Roman-Lopes (2019), its
spectral type is O9.2 IV(n). By comparing with standard stars in GOSSS, its
spectral type is more like O9.7 V.

_LAMOST-O 126 = GSC 03719-00546_. In Molina Lera et al. (2018), its spectral
type is O9.5 V. Its LAMOST spectrum is O9.7 V.

Figure 16: Spectra of LAMOST-O 111, 112, 114, 115, 116, 117, 118, 119, 120,
122, 123, 125, and 126.

The following 13 stars are shown in Figure 17.

_LAMOST-O 127 = BD+52 805_. This star is also in Maíz Apellániz et al. (2016)
with a spectral type of O8 V(n). But both He II $\lambda$4200/He I
$\lambda$4144 and He II $\lambda$4542/He I $\lambda$4388 are around 1, which
suggest its spectral type should be O9. But, its rotation is indiscernible
from the low resolution of the LAMOST spectrum. As a result, its spectral type
should be O9 V. Moreover, it seems that there is a wavelength shift between
GOSSS and LAMOST spectra ($\Delta V\sim 32$ km s-1). Thus, it may be an SB1.

_LAMOST-O 128 = LS V +53 21_. In Hardorp et al. (1965), its spectral type is
OB+. Its LAMOST spectrum is O9.7 II.

_LAMOST-O 129 = TYC 3719-1248-1_. It is an eclipsing binary with a period of
5.0254 days (Collins et al., 2018).

_LAMOST-O 132 = LS V +51 18_. In Skiff (2014), its spectral type is OB. Its
LAMOST spectrum is O7.5 V.

_LAMOST-O 133 = TYC 3732-701-1_. In Liu et al. (2019), its spectral type is B.
Its new spectral type is O9.7 III.

_LAMOST-O 134 = TYC 3732-745-1_. In Liu et al. (2019), its spectral type is B.
Its new spectral type is O9.7 III(n).

_LAMOST-O 136 = $\xi$ Per_. This spectrum is 28”.65 away from $\xi$ Per, but
by comparing with its GOSSS spectrum in Sota et al. (2011), its LAMOST
spectrum is well consistent with its GOSSS spectrum, but with a $\Delta V\sim
42$ km s-1.

_LAMOST-O 137 = UCAC4 676-031103_. In Roman-Lopes & Roman-Lopes (2019), its
spectral type is O8 V((f)). But its He II $\lambda$4542 is obviously weaker
than He I $\lambda$4388, which suggests its spectral type is more like O9.5,
while its luminosity seems more like III based on He II $\lambda$4686/He I
$\lambda$4713\. As a result, it is classified as O9.5 III.

_LAMOST-O 138 = HD 41 161_. This spectrum is 7.48” away from HD 41 161, but
its LAMOST spectrum is consistent well with GOSSS spectrum (Sota et al.,
2011), but with a $\Delta V\sim 34$ km s-1. Thus, it may be an SB1.

_LAMOST-O 140 = TYC 2895-2762-1_. In Liu et al. (2019), its spectral type is
B. But its LAMOST spectrum should be O9.7 II, and its He II $\lambda$4686
shows emission with an inverse in it. As a result, it is classified as O9.7
IIp.

_LAMOST-O 142 = HD 278 247_. In Roman-Lopes & Roman-Lopes (2019), its spectral
type is also O4 V((f)).

_LAMOST-O 143 = ALS 19710_. In Liu et al. (2019), its spectral type is O8.5.
But it should be O9.2 V.

_LAMOST-O 145 = V* AE Aur_. This spectrum is 13”.15 away from AE Aur. By
comparing with the GOSSS spectrum in Sota et al. (2011), the LAMOST spectrum
is well consistent with the GOSSS spectrum, but with a $\Delta V\sim 38$ km
s-1, which suggests it is an SB1.

Figure 17: Spectra of LAMOST-O 127, 128, 129, 132, 133, 134, 136, 137, 138,
140, 142, 143, and 145.

The following 13 stars are shown in Figure 18.

_LAMOST-O 147 = LS V +35 24_. In Georgelin et al. (1973) and Liu et al.
(2019), its spectral types are O9 V. But LAMOST spectral type is O9.7 III.

_LAMOST-O 148 = UCAC2 43411288_. In Roman-Lopes & Roman-Lopes (2019), its
spectral type is also O9 V.

_LAMOST-O 151 = HD 37 032_. This spectrum is 4”.27 away from HD 37 032. In
VizieR, the spectral type of HD 37 032 is B or OB. Its LAMOST spectrum is O9.7
III.

_LAMOST-O 152 = HD 37 366_. This spectrum is 7”.48 away from HD 37 366, but
the LAMOST spectrum is consistent well with the GOSSS spectrum (Sota et al.,
2011).

_LAMOST-O 153 = HD 37 424_. Its spectral type is B9 in most catalogs in
VizieR, while it is B2 II in Chargeishvili (1988). Its LAMOST spectrum is
O9.7. The ratio of He II $\lambda$4686/He I $\lambda$4713 indicates that its
luminosity is II, but its weak Si IV $\lambda$4089 and 4116 indicate it is a
dwarf. Thus, its luminosity is unclear.

_LAMOST-O 154_. In Liu et al. (2019), its spectral type is O, but it should be
O7 V.

_LAMOST-O 156 = BD+26 980_. In Roman-Lopes & Roman-Lopes (2019), its spectral
type is O9.5 V(n), but it is more like O9.7 III.

_LAMOST-O 157_. In Liu et al. (2019), its spectral type is O9 III. This star
was mistaken for TYC 1867-418-1 by Roman-Lopes & Roman-Lopes (2019), and was
assigned to O7.5 III((f)). But LAMOST spectrum shows it is an O9 V, without N
III $\lambda$4636/40/42 emission.

_LAMOST-O 158_. In Simbad, there is no spectral information about this star.
Its LAMOST spectrum is O9 V.

_LAMOST-O 160 = HD 251 204_. In Simbad, its spectral type is B or OB. Its
LAMOST spectrum is O9.7 II.

_LAMOST-O 163 = LS V +21 27_. In Roman-Lopes & Roman-Lopes (2019), its
spectral type is O9.5 IV, but it is more like O9.7 V.

_LAMOST-O 164 = HD 254 755_. This spectrum is 5.03” away from HD 254 755. In
Skiff (2014), the spectral type of HD 254 755 is O9 or OB. In Simbad, HD 254
755 is a double or multiple star. Its LAMOST spectrum is O8.5 III((f)).

_LAMOST-O 165 = HD 256 035_. This spectrum is 4.62” away from HD 256 035. In
Skiff (2014), the spectral type of HD 256 035 is O9 or OB. Its LAMOST spectrum
is O9.2 Vn.

Figure 18: Spectra of LAMOST-O 147, 148, 151, 152, 153, 154, 156, 157, 158,
160, 163, 164, and 165.

The following 13 stars are shown in Figure 19.

_LAMOST-O 166_. In Liu et al. (2019), its spectral type is O9 III, but it is
more like O9 V.

_LAMOST-O 167 = HD 252 325_. In Roman-Lopes & Roman-Lopes (2019), its spectral
type is O9 V(n). But it is more like O9.5 V.

_LAMOST-O 168 = HD 44 597_. This spectrum is 3”.30 away from HD 44 597. In Liu
et al. (2019), its spectral type is O9 V. Here, it is O9.5 V.

_LAMOST-O 169 = LS V +19 5_. In Maíz Apellániz et al. (2016), its spectral
type is also O9.5 V, but most lines are a little shallower in LAMOST spectrum.

_LAMOST-O 170 = UCAC4 534-022196_. In Roman-Lopes & Roman-Lopes (2019), its
spectral type is O9.5 IV((n)). Here, it is O9.5 V.

_LAMOST-O 171 = HD 253 247_. In Liu et al. (2019), its spectral type is O.
Here, it is O9.7 V.

_LAMOST-O 173 = HD 253 327_. In Liu et al. (2019), its spectral type is B. Its
LAMOST spectrum clearly is O9.7. However, its luminosity is unclear, because
He II $\lambda$4686/He I $\lambda$4713 suggests II, but Si IV $\lambda$4089 is
very weak.

_LAMOST-O 174 = LS 19_. In Ojha et al. (2011), its spectral type is O9.5 V.
Its LAMOST spectrum is O9.7 V.

_LAMOST-O 175 = HD 41 997_. This spectrum is 10”.08 away from HD 41 997. In
Sota et al. (2011), the spectral type of HD 41 997 is O7.5 Vn((f)). The
signal-to-noise ratio of the LAMOST spectrum is very low, but by comparing the
spectra of LAMOST and GOSSS, they seem well consistent with each other. Thus,
the GOSSS spectral type 7.5 Vn((f)) is adopted.

_LAMOST-O 176_. In Liu et al. (2019), its spectral type is O. Here, it is O9.5
V(n).

_LAMOST-O 177_. In Liu et al. (2019), its spectral type is B. Here, it is O9.7
III.

_LAMOST-O 178 = TYC 1315-1502-1_. There is no spectral information for this
star in Simbad. Its LAMOST spectrum is O8 V.

_LAMOST-O 179 = HD 252 845_. This spectrum is 4”.14 away from HD 252 845. In
Roman-Lopes & Roman-Lopes (2019), the spectral type is O9 V:nn, but it should
be O9.5 V(n).

Figure 19: Spectra of LAMOST-O 166, 167, 168, 169, 170, 171, 173, 174, 175,
176, 177, 178, and 179.

The following 13 stars are shown in Figure 20.

_LAMOST-O 180 = HD 252 956_. This spectrum is 4”.42 away from HD 252 956. In
Skiff (2014), the spectral type is OB or B. Its LAMOST spectrum is O9.7 III.

_LAMOST-O 181 = HD 254 428_. This spectrum is 4”.90 away from HD 254 428. In
VizieR, the spectral type is OB or around B0. Its LAMOST spectrum is O9.5 IV.

_LAMOST-O 182_. In Simbad, this spectrum is 5”.50 away from ALS 18672 and
1”.66 away from the radio source NVSS J061453+122122, respectively. These
three sources should be the same star in Aladin by eye inspection. In Liu et
al. (2019), the spectral type is B. Here, it is O9.7 III.

_LAMOST-O 183 = 15 Mon_. This spectrum is 21”.19 away from 15 Mon. In Skiff
(2014), the spectral type is O7V + B1.5/2V. Its LAMOST spectrum seems O6.5 V.

_LAMOST-O 184 = HD 46 966_. This spectrum is 11”.54 away from HD 46 966. This
star is the O8.5 IV standard star in GOSSS. Compared with the GOSSS spectrum,
He II $\lambda$4200 He II$\lambda$4388, He I $\lambda$4471, He II
$\lambda$4542, and H$\gamma$ in the LAMOST spectrum become stronger. As a
result, the LAMOST spectrum is more like the GOSSS O8 V standard star HD 101
223. Thus, it is assigned O8 V.

_LAMOST-O 186 = HD 46 149_. This spectrum is 8”.95 away from HD 46 149. This
star is also in GOSSS (Sota et al., 2011). The spectra of LAMOST and GOSSS are
well consistent with each other.

_LAMOST-O 187 = HD 46 056_. This spectrum is 6”.91 away from HD 46 056. This
star is also in GOSSS (Sota et al., 2011). The spectra of LAMOST and GOSSS are
well consistent with each other.

_LAMOST-O 188 = HD 258 691_. In Simbad, its spectral type is O9 V. Its LAMOST
spectral type is O9.5 V.

_LAMOST-O 189 = HD 46 485_. This spectrum is 8”.77 away from HD 46 485. This
star is also in GOSSS (Sota et al., 2014). The signal-to-noise ratio of the
LAMOST spectrum is low, but the spectra of LAMOST and GOSSS seem wekk
consistent with each other. Thus, the GOSSS spectral type O7 V((f))nzvar? is
adopted.

_LAMOST-O 190 = UCAC4 479-024664_. In Roman-Lopes & Roman-Lopes (2019), its
spectral type is O9.7 IV(n). Though low signal-to-noise ratio, it seems to be
an O9.5 III.

_LAMOST-O 191 = LS VI +04 36_. Its spectral type in Roman-Lopes & Roman-Lopes
(2019) is also O8.5 III.

_LAMOST-O 192 = HD 46 847_. In Negueruela et al. (2004), its spectral type is
O9.7 IV. Its LAMOST spectrum is O9.7 III.

_LAMOST-O 193 = HD 46 573_. This spectrum is 11”.46 away from HD 46 573. This
star is also in GOSSS (Sota et al., 2011). The signal-to-noise ratio of the
LAMOST spectrum is low, but the spectra of LAMOST and GOSSS seem consistent
with each other. Thus, the GOSSS spectral type O7 V((f))z is adopted.

Figure 20: Spectra of LAMOST-O 180, 181, 182, 183, 184, 186, 187, 188, 189,
190, 191, 192, and 193.

The following 10 stars are shown in Figure 21.

_LAMOST-O 194 =UCAC4 463-019987_. In Roman-Lopes & Roman-Lopes (2019), its
spectral type is O8 V((f))e. Here, it is O9.2 V.

_LAMOST-O 195 = TYC 147-1026-1_. In Russeil et al. (2007), its spectral type
is O7 V. Its LAMOST spectrum is O7 V((f)).

_LAMOST-O 196 = LS VI +02 20_. In Nassau et al. (1965), its spectral type is
OB. Its LAMOST spectrum is O9.2. However, its luminosity is unclear, because
He II $\lambda$4686/He I $\lambda$4713 suggests II, but there are not Si IV
$\lambda$4089 and 4116.

_LAMOST-O 197 = HD 292 167_. In Negueruela et al. (2015), its spectral type is
O8.5 Ib(f). The emission of N III $\lambda$4634/40/42 is very weak in the
LAMOST spectrum, while Si IV $\lambda$4089 and 4116 are not strong enough to
be Ib, so its spectral type is O8.5 II((f)).

_LAMOST-O 198 = HD 289 291_. In Hiltner & Johnson (1956), its spectral type is
O8:. Its LAMOST spectrum is O9.2 III(n).

_LAMOST-O 200 = TYC 148-2577-1_. In Sebastian et al. (2012), its spectral type
is B1 V. Its LAMOST spectral type is O7.5 V.

_LAMOST-O 202 = TYC 148-2536-1_. In Negueruela et al. (2015), its spectral
type is O6 V((f)). Its LAMOST spectral type is O6.5 V((f)).

_LAMOST-O 203 = LS VI +00 25_ In Munari & Tomasella (1999), it is an O7 V SB1,
with a period of 11.030 days. Its LAMOST spectrum is O9.5 V.

_LAMOST-O 204 = HD 292 392_. In Negueruela et al. (2015), its spectral type is
also O8.5 V. Moreover, its LAMOST spectrum shows it is also a fast rotator,
thus an O8.5 Vn star.

_LAMOST-O 207 = TYC 4800-1443-1_. In McCuskey (1956), its spectral type is
B0:. Its LAMOST spectrum is O9.5 V.

_LAMOST-O 208 = UCAC4 436-021292_. In Sebastian et al. (2012), its spectral
type is B0.5 Ia. Its LAMOST spectrum is O9 V.

_LAMOST-O 209 = LS VI -04 5_. In Nassau et al. (1965), its spectral type is
OB. Its LAMOST spectrum is O9.5 V.

Figure 21: Spectra of LAMOST-O 194, 195, 196, 197, 198, 200, 202, 203, 204,
207, 208, and 209.

##  5 Summary

This paper publishes 209 O-type stars with their spectra found in the LAMOST
database up to 2018. Ninety-four new stars are firstly given. The spectral
classification standards are from Sota et al. (2011, 2014) and Maíz Apellániz
et al. (2016). All spectra in this paper are compared with standard stars in
Table 2 in Maíz Apellániz et al. (2016) to determine spectral types. But there
are still many stars that cannot be assigned correct spectral types because of
the influence of their company and/or other unknown reasons.

For a star that has multiple LAMOST spectra from different epochs, or has both
LAMOST and GOSSS spectra, all these spectra are compared to inspect spectral
variations or/and wavelength shifts to find binaries.

All LAMOST low- and medium-resolution spectra shown in this paper are provided
in the China-VO PaperData repository: doi:10.12149/101049

The author thanks the anonymous referee for very helpful comments. This
research is supported by the National Natural Science Foundation of China
(NSFC; grant No. 12073038). The author acknowledges the support from
Cultivation Project for LAMOST Scientific Payoff and Research Achievement of
CAMS-CAS. The author acknowledges the support from the Chinese Space Station
Telescope (CSST) project. Guoshoujing Telescope (the Large Sky Area Multi-
Object Fiber Spectroscopic Telescope LAMOST) is a National Major Scientific
Project built by the Chinese Academy of Sciences. Funding for the project has
been provided by the National Development and Reform Commission. LAMOST is
operated and managed by the National Astronomical Observatories, Chinese
Academy of Sciences.

Table 1: Spectral Information for 209 LAMOST O-type Stars

LAMOST Name | R. A.(deg) | Decl.(deg) | Simbad Name | Dist (arcsec) | SpT | Mult | New
---|---|---|---|---|---|---|---
LAMOST-O 001 | 279.765732 | -7.859846 | HD 172 175 |  | O6 I(n)fp |  |
LAMOST-O 002 | 280.401734 | -5.956290 | TYC 5125-2083-1 |  | O9 II |  | T
LAMOST-O 003 | 281.144639 | -5.939243 | TYC 5125-3040-1 |  | O + O | SB2 | T
LAMOST-O 004 | 281.894538 | -6.307544 | HD 173 820 |  | O8.5 V |  | T
LAMOST-O 005 | 282.126703 | -5.519835 | BD-05 4769 |  | O7.5 III((f)) |  |
LAMOST-O 006 | 281.251027 | -4.508252 |  |  | O7.5 II((f)) |  | T
LAMOST-O 007 | 281.357364 | -4.016850 | LS IV -04 20 |  | O9.7 II-IIIn |  | T
LAMOST-O 008 | 281.233639 | -3.812636 | TYC 5121-769-1 |  | O8 Ib((f)) |  | T
LAMOST-O 009 | 282.456935 | -4.327860 | BD-04 4593 |  | O9.7 II |  |
LAMOST-O 010 | 282.608507 | -4.248241 | TYC 5122-465-1 |  | O9 IIIne |  | T
LAMOST-O 011 | 281.709165 | -3.730182 | ALS 19303 |  | O7 V |  | T
LAMOST-O 012 | 277.755725 | 13.503585 | TYC 1036-450-1 |  | O9.7 | SB1 |
LAMOST-O 013 | 295.051991 | 23.627912 | LS II +23 14 |  | O9.7 IIIne |  | B
LAMOST-O 014 | 300.340211 | 22.291709 | HD 345 475 |  | O9.7 II |  | T
LAMOST-O 015 | 294.743911 | 26.145659 |  |  | O9.7 II |  | T
LAMOST-O 016 | 296.425477 | 25.354556 | HD 338 916 |  | O7.5 Vz |  |
LAMOST-O 017 | 300.825136 | 30.651276 |  |  | O9.5 V |  | T
LAMOST-O 018 | 305.805612 | 37.286904 | [NH52] 74 |  | O9.7 IV |  | B
LAMOST-O 019 | 305.927422 | 37.899148 | BD+37 3917 |  | O9.7 II |  | T
LAMOST-O 020 | 304.948209 | 38.595413 | HD 228 943 |  | O9.7 III(n) | SB1 |
LAMOST-O 021 | 306.029716 | 38.022734 | TYC 3152-1390-1 |  | O9.7 IV |  | T
LAMOST-O 022 | 305.586713 | 38.724021 | HD 194 094 |  | O9 III |  |
LAMOST-O 023 | 307.398459 | 40.408733 | TYC 3156-1881-1 |  | O7 Vz | SB1 |
LAMOST-O 024 | 307.406578 | 40.852362 | UCAC4 655-091969 |  | O8 III((f)) |  | B
LAMOST-O 025 | 308.160176 | 40.679025 | [CPR2002] A25 |  | O8 III |  |
LAMOST-O 026 | 307.740527 | 41.165973 | [CPR2002] A26 |  | O9 III |  |
LAMOST-O 027 | 308.295679 | 41.252285 | Schulte 9 |  | O4.5 If | SB1 |
LAMOST-O 028 | 307.665858 | 41.614064 | GSC 03161-01264 |  | O6.5 Vz |  |
LAMOST-O 029 | 307.956907 | 41.474032 | Schulte 20 |  | O9.7 IV | SB1 |
LAMOST-O 030 | 308.404145 | 41.269810 | Schulte 70 |  | O9.5 III(n) | SB1 |
LAMOST-O 031 | 308.208404 | 41.395749 | Schulte 17 |  | O8 V | SB1 |
LAMOST-O 032 | 308.420264 | 41.505266 | GSC 03161-01086 |  | O7 Vz |  |
LAMOST-O 033 | 308.443380 | 41.550192 | BD+41 3804 |  | O9.7 Iab |  |
LAMOST-O 034 | 308.556298 | 41.584122 | Schulte 29 |  | O7 V(n)((f))z |  |
LAMOST-O 035 | 308.741030 | 41.731738 | RLP 1252 |  | O8 Ve |  | B
LAMOST-O 036 | 306.576874 | 43.796454 | UCAC4 669-086327 |  | O4 IV(fc)p |  | B
LAMOST-O 037 | 308.842778 | 43.925132 | 2MASS J20352227+4355304 |  | O9.7 II |  | B
LAMOST-O 038 | 331.984167 | 54.518333 | BD+53 2790 |  | O9.2 ne |  |
LAMOST-O 039 | 334.491164 | 54.467304 | V* AW Lac |  | B n + O9.5 Vn | SB2 | T
LAMOST-O 040 | 335.560943 | 54.800355 | HD 235 813 |  | O9.7 II |  | T
LAMOST-O 041 | 337.475207 | 55.407962 | BD+54 2789 |  | O9.2 V + B | SB2 | T
LAMOST-O 042 | 343.384265 | 52.638135 | HD 235 989 |  | O9.2 IIInn |  | T
LAMOST-O 043 | 343.938150 | 56.476847 | LS III +56 109 |  | O5.5 V(n)((fc)) | SB1 |
LAMOST-O 044 | 343.765772 | 57.620883 | LS III +57 99 |  | O8.5 Vn + O8.5 Vn | SB2 | T
LAMOST-O 045 | 344.807124 | 58.745279 | LS III +58 70 |  | O9.7 IV |  | T
LAMOST-O 046 | 343.422151 | 60.318421 |  |  | O9 II |  | T
LAMOST-O 047 | 347.142318 | 56.016970 | HD 240 197 |  | ON9.7 (n)e |  | T
LAMOST-O 048 | 345.028540 | 59.324992 | BD+58 2520 |  | O9.2 V |  | T
LAMOST-O 049 | 346.952327 | 61.162029 |  |  | O8 V((f)) |  | T
LAMOST-O 050 | 348.455916 | 59.640248 |  |  | O9 V |  | T
LAMOST-O 051 | 348.648781 | 59.553593 | Hilt 1202 |  | O9.7 IIn |  | T
LAMOST-O 052 | 348.128234 | 60.215052 |  |  | O9.5 V |  | T
LAMOST-O 053 | 348.643591 | 59.836733 | HD 240 234 |  | O9.7 V(n)e |  | T
LAMOST-O 054 | 348.701002 | 59.921967 | LS III +59 58 |  | O9.5 Vn |  | T
LAMOST-O 055 | 349.080820 | 59.455806 | LS III +59 63 |  | O7 III(n)((f)) |  | T
LAMOST-O 056 | 349.148451 | 59.764180 |  |  | O9.5 V + O9.5 V | SB2 | T
LAMOST-O 057 | 349.032066 | 60.042411 | TYC 4279-1192-1 |  | O9.5 V |  |
LAMOST-O 058 | 349.273683 | 59.912731 | IRAS 23149+5938 |  | O9.7 III |  | T
LAMOST-O 059 | 349.304273 | 60.107976 | TYC 4279-982-1 |  | O9 Vn |  | T
LAMOST-O 060 | 348.954883 | 61.133210 |  |  | O8 V + B | SB2 |
LAMOST-O 061 | 353.198135 | 59.951567 | LS I +59 5 |  | O7.5 V((f)) |  | T
LAMOST-O 062 | 354.175239 | 58.657754 | LS III +58 86 |  | O7 V(n)z |  | T
LAMOST-O 063 | 353.236693 | 60.662131 | LS I +60 8 |  | O9.5 III |  |
LAMOST-O 064 | 353.405331 | 60.558938 | LS I +60 9 |  | O7 Vn((f))z |  | T
LAMOST-O 065 | 353.810688 | 60.006449 | EM* GGR 149 |  | O9.7 V(n)e |  | B
LAMOST-O 066 | 353.403528 | 60.752068 |  |  | O9.5 V |  |
LAMOST-O 067 | 353.385451 | 60.792254 |  |  | O9: V |  |
LAMOST-O 068 | 353.408224 | 61.079876 | LS I +60 10 |  | O7.5 Vz |  | T
LAMOST-O 069 | 354.964232 | 60.091374 | LS I +59 11 |  | O7.5 III((f)) |  | T
LAMOST-O 070 | 355.758156 | 59.065586 | BD+58 2636 |  | O9.2 III |  | T
LAMOST-O 071 | 355.546938 | 60.943279 | TYC 4280-103-1 |  | O9.7 IV |  | T
LAMOST-O 072 | 356.403122 | 59.906001 | V* QQ Cas |  | O8 Vn + O9 Vn | SB2 | T
LAMOST-O 073 | 354.909499 | 62.666785 | LS I +62 4 |  | O9.5 V | SB1 | T
LAMOST-O 074 | 355.944044 | 61.450150 | LS I +61 28 |  | ON8.5 Vn |  | B
LAMOST-O 075 | 356.519854 | 61.783478 | LS I +61 50 |  | O7.5 Vn |  | T
LAMOST-O 076 | 356.369232 | 63.271331 | LS I +62 14 |  | O5: Iafpe |  | T
LAMOST-O 077 | 358.248421 | 60.481672 | LS I +60 50 |  | O9.5 III |  |
LAMOST-O 078 | 358.169361 | 60.993612 | BD+60 2632 |  | O9.5 IV |  | T
LAMOST-O 079 | 358.351876 | 60.680337 | HD 240 435 |  | O9.7 III |  | T
LAMOST-O 080 | 358.271744 | 60.912417 | BD+60 2635 |  | O6 V((f)) | SB1 |
LAMOST-O 081 | 357.221270 | 63.005322 | LS I +62 25 |  | O9.7 III | SB1 | T
LAMOST-O 082 | 357.018620 | 63.397473 | BD+62 2299 |  | O8 II((f)) |  | T
LAMOST-O 083 | 359.296667 | 60.485096 | LS I +60 62 |  | O8.5 V |  | T
LAMOST-O 084 | 359.712130 | 60.264174 | HD 240 464 |  | O9.5 V | SB1 |
LAMOST-O 085 | 18.648234 | 57.924769 | HD 236 672 |  | ON9 IVn |  | B
LAMOST-O 086 | 32.375302 | 58.783764 | HD 13 022 |  | O9.7 II-III | SB1 |
LAMOST-O 087 | 33.124871 | 59.901163 | Hilt 233 |  | O8 V + B0: V | SB2 |
LAMOST-O 088 | 35.687196 | 61.839935 | LS I +61 266 |  | O6 Vz |  | T
LAMOST-O 089 | 36.150672 | 61.687750 | LS I +61 267 |  | O7 V(n) |  | T
LAMOST-O 090 | 31.627886 | 54.519031 |  |  | O9.7 V |  | T
LAMOST-O 091 | 37.578910 | 63.289281 | LS I +63 187 |  | O9.7 III |  | T
LAMOST-O 092 | 36.643315 | 62.011796 | BD+61 411 |  | O7 V((f))z | SB1 |
LAMOST-O 093 | 38.798195 | 63.584176 | BD+62 419 |  | O9.7 III |  | T
LAMOST-O 094 | 35.544578 | 59.549696 | HD 14 442 |  | O5 Infp | SB1 |
LAMOST-O 095 | 37.376963 | 61.495595 | V* KM Cas |  | O9 Vne |  | B
LAMOST-O 096 | 39.075907 | 62.948151 | BD+62 424 |  | O6 V((f)) | SB1 |
LAMOST-O 097 | 38.045221 | 61.552210 | BD+60 498 |  | O9.7 IV | SB1 |
LAMOST-O 098 | 38.069798 | 61.554168 | BD+60 499 |  | O9.5 V | SB1 |
LAMOST-O 099 | 38.151151 | 61.473773 | BD+60 501 |  | O7 V(n)((f))z | SB1 |
LAMOST-O 100 | 36.004714 | 58.323855 | HD 14 645 |  | O9.7 IIIne |  | T
LAMOST-O 101 | 35.799014 | 57.472052 | BD+56 594 |  | O7.5 Vz |  | T
LAMOST-O 102 | 38.309007 | 60.022766 | LS I +59 139 |  | O9.7 IV |  | T
LAMOST-O 103 | 38.059327 | 59.621146 | TYC 3699-1537-1 |  | O9.7 IV |  | T
LAMOST-O 104 | 41.294227 | 62.890463 | LS I +62 223 |  | O6.5 Vz + O9 V | SB2 | T
LAMOST-O 105 | 40.284160 | 61.135197 | BD+60 544 |  | O9.7 III | SB1 | T
LAMOST-O 106 | 42.250807 | 62.535328 | Lan 27 |  | O9.2 V |  | T
LAMOST-O 107 | 40.836558 | 60.836840 |  |  | O9.7 V |  | T
LAMOST-O 108 | 42.213030 | 62.216246 | LS I +62 227 |  | O9.7 Ib + O9 V | SB2 | T
LAMOST-O 110 | 42.884097 | 62.222594 |  |  | O9.5 IV |  |
LAMOST-O 111 | 41.542071 | 60.266033 | 2MASS J02461010+6015576 |  | O |  | T
LAMOST-O 112 | 42.276544 | 60.560702 | LS I +60 263 |  | O7 III((f)) |  | T
LAMOST-O 113 | 44.267202 | 61.416018 | BD+60 594 |  | O8.5 Vn | SB1 |
LAMOST-O 114 | 35.715712 | 41.480129 | HD 14 633 | 28.34 | O |  |
LAMOST-O 115 | 50.872389 | 55.206651 | LS I +55 47 |  | O9.5 IV |  |
LAMOST-O 116 | 59.170522 | 57.257971 | LS I +57 136 |  | O9.2 V |  |
LAMOST-O 117 | 59.870331 | 57.118007 | BD+56 866 |  | O9.2 V(n) |  |
LAMOST-O 118 | 57.217761 | 53.149000 |  |  | O |  | T
LAMOST-O 119 | 61.244651 | 55.909252 | LS V +55 12 |  | O9.7 II |  | T
LAMOST-O 120 | 61.841915 | 55.507740 | TYC 3722-435-1 |  | O9.2 V |  | T
LAMOST-O 121 | 61.682058 | 54.396626 | LAMOST J040643.69+542347.8 |  | O6.5 Vnnn((f))p |  | B
LAMOST-O 122 | 60.836444 | 51.314594 | BD+50 886 |  | O4 V((c)) | SB1 |
LAMOST-O 123 | 65.255647 | 53.609539 | LS V +53 20 |  | O9.2 V |  | B
LAMOST-O 124 | 61.470965 | 51.116128 | TYC 3339-851-1 |  | O6 Vz |  | B
LAMOST-O 125 | 63.074008 | 52.030896 | LS V +51 16 |  | O9.7 V |  | B
LAMOST-O 126 | 64.964828 | 53.158056 | GSC 03719-00546 |  | O9.7 V |  |
LAMOST-O 127 | 64.649308 | 52.865094 | BD+52 805 |  | O9 V | SB1 |
LAMOST-O 128 | 65.292516 | 53.171164 | LS V +53 21 |  | O9.7 II |  | T
LAMOST-O 129 | 65.353371 | 52.950100 | TYC 3719-1248-1 |  | O9.7 IV(n) |  | T
LAMOST-O 130 | 62.794727 | 50.708221 | TYC 3340-2437-1 |  | O9.7 III | SB1 | T
LAMOST-O 131 | 59.715117 | 48.301529 | LS V +48 9 |  | O9.7 n | SB1 | B
LAMOST-O 132 | 65.191785 | 51.893107 | LS V +51 18 |  | O7.5 V |  | T
LAMOST-O 133 | 67.748920 | 52.664967 | TYC 3732-701-1 |  | O9.7 III |  | T
LAMOST-O 134 | 67.653280 | 52.581847 | TYC 3732-745-1 |  | O9.7 III(n) |  | T
LAMOST-O 135 | 63.833789 | 48.513409 | LS V +48 12 |  | O9.5 Binary | SB2 | B
LAMOST-O 136 | 59.740276 | 35.798951 | ksi Per | 28.65 | O7.5 III(n)((f)) | SB1 |
LAMOST-O 137 | 72.580300 | 45.013304 | UCAC4 676-031103 |  | O9.5 III |  | B
LAMOST-O 138 | 91.467910 | 48.247255 | HD 41 161 | 7.48 | O8 Vn | SB1 |
LAMOST-O 139 | 79.594814 | 41.935024 | HD 277 878 |  | O7 V((f))z | SB1 | B
LAMOST-O 140 | 77.457310 | 37.586155 | TYC 2895-2762-1 |  | O9.7 IIp |  | T
LAMOST-O 141 | 80.002659 | 38.912102 | LS V +38 12 |  | O6.5 V((f)) + B0 III-V | SB2 |
LAMOST-O 142 | 81.810394 | 39.852325 | HD 278 247 |  | O4 V((f)) |  | B
LAMOST-O 143 | 78.358283 | 37.446234 | ALS 19710 |  | O9.2 V |  | B
LAMOST-O 144 | 82.521290 | 38.440365 | LS V +38 15 |  | O9 V + B | SB2 | B
LAMOST-O 145 | 79.072462 | 34.314875 | V* AE Aur | 13.15 | O9.5 V | SB1 |
LAMOST-O 146 | 81.889888 | 34.450499 | LS V +34 21 |  | O9 IV | SB1 | B
LAMOST-O 147 | 84.940781 | 35.898988 | LS V +35 24 |  | O9.7 III |  |
LAMOST-O 148 | 80.692431 | 33.422328 | UCAC2 43411288 |  | O9 V |  | B
LAMOST-O 149 | 80.665368 | 33.371715 | LS V +33 15 |  | O5.5 Vz((f)) var | SB1 |
LAMOST-O 150 | 80.666955 | 33.319217 | HD 242 926 |  | O7 Vz |  |
LAMOST-O 151 | 84.288511 | 34.811139 | HD 37 032 | 4.27 | O9.7 III |  | T
LAMOST-O 152 | 84.853588 | 30.892837 | HD 37 366 | 7.48 | O9.5 IV |  |
LAMOST-O 153 | 84.934992 | 27.780888 | HD 37 424 |  | O9.7 |  | T
LAMOST-O 154 | 87.241714 | 27.352786 |  |  | O7 V |  | B
LAMOST-O 155 | 91.741272 | 29.058012 | LS V +29 22 |  | O9.7 | SB1 | T
LAMOST-O 156 | 87.980878 | 27.032787 | BD+26 980 |  | O9.7 III |  | B
LAMOST-O 157 | 88.059307 | 25.125726 |  |  | O9 V |  | B
LAMOST-O 158 | 90.290288 | 25.595077 |  |  | O9 V |  | T
LAMOST-O 159 | 96.249449 | 26.822050 | RL 128 |  | O4.5 V((c))z |  | B
LAMOST-O 160 | 91.273607 | 23.394041 | HD 251 204 |  | O9.7 II |  | T
LAMOST-O 161 | 94.923153 | 23.289703 | HD 255 055 |  | O9.2 IVe |  | B
LAMOST-O 162 | 95.135680 | 23.317320 | HD 255 312 |  | O6 Vzn + O9 Vn | SB2 | T
LAMOST-O 163 | 92.133750 | 21.610911 | LS V +21 27 |  | O9.7 V |  | B
LAMOST-O 164 | 94.633763 | 22.678598 | HD 254 755 | 5.03 | O8.5 III((f)) |  |
LAMOST-O 165 | 95.744063 | 22.862915 | HD 256 035 | 4.62 | O9.2 Vn |  |
LAMOST-O 166 | 91.091069 | 20.273966 |  |  | O9 V |  | B
LAMOST-O 167 | 92.251298 | 20.640514 | HD 252 325 |  | O9.5 V |  | B
LAMOST-O 168 | 95.869889 | 20.392120 | HD 44 597 | 3.30 | O9.5 V |  | B
LAMOST-O 169 | 96.257907 | 19.848470 | LS V +19 5 |  | O9.5 V |  |
LAMOST-O 170 | 90.245143 | 16.668620 | UCAC4 534-022196 |  | O9.5 V |  | B
LAMOST-O 171 | 93.092140 | 18.016080 | HD 253 247 |  | O9.7 V |  | B
LAMOST-O 172 | 95.427815 | 19.160047 | TYC 1323-1592-1 |  | O8.5 Vz |  | B
LAMOST-O 173 | 93.184080 | 17.987310 | HD 253 327 |  | O9.7 (n) |  | T
LAMOST-O 174 | 93.267560 | 17.978180 | LS 19 |  | O9.7 V |  |
LAMOST-O 175 | 92.230628 | 15.702989 | HD 41 997 | 10.08 | O7.5 Vn((f)) |  |
LAMOST-O 176 | 94.637895 | 15.279759 |  |  | O9.5 V(n) |  | B
LAMOST-O 177 | 94.564093 | 15.131532 |  |  | O9.7 III |  | T
LAMOST-O 178 | 94.889682 | 15.293595 | TYC 1315-1502-1 |  | O8 V |  | T
LAMOST-O 179 | 92.700002 | 13.183337 | HD 252 845 | 4.14 | O9.5 V(n) |  | B
LAMOST-O 180 | 92.776887 | 13.145328 | HD 252 956 | 4.42 | O9.7 III |  | T
LAMOST-O 181 | 94.225125 | 13.508074 | HD 254 428 | 4.49 | O9.5 IV |  | T
LAMOST-O 182 | 93.722302 | 12.356639 |  | 5.50 | O9.7 III |  | T
LAMOST-O 183 | 100.239310 | 9.892698 | 15 Mon | 21.19 | O6.5 V |  |
LAMOST-O 184 | 99.107929 | 6.086396 | HD 46 966 | 11.54 | O8 V |  |
LAMOST-O 185 | 100.500080 | 6.342522 | HD 48 099 | 15.73 | O5 V((f))z + O9:V | SB2 |
LAMOST-O 186 | 97.970212 | 5.035209 | HD 46 149 | 8.95 | O8.5 V |  |
LAMOST-O 187 | 97.835875 | 4.832788 | HD 46 056 | 6.91 | O8 Vn |  |
LAMOST-O 188 | 97.638789 | 4.690992 | HD 258 691 |  | O9.5 V |  |
LAMOST-O 189 | 98.461242 | 4.527636 | HD 46 485 | 8.77 | O7 V((f))nzvar? |  |
LAMOST-O 190 | 101.434850 | 5.736885 | UCAC4 479-024664 |  | O9.5 III |  | B
LAMOST-O 191 | 102.041760 | 4.821117 | LS VI +04 36 |  | O8.5 III |  | B
LAMOST-O 192 | 98.932530 | 2.711233 | HD 46 847 |  | O9.7 III |  |
LAMOST-O 193 | 98.597772 | 2.537304 | HD 46 573 | 11.46 | O7 V((f))z |  |
LAMOST-O 194 | 98.646611 | 2.456512 | UCAC4 463-019987 |  | O9.2 V |  | B
LAMOST-O 195 | 99.557164 | 0.736640 | TYC 147-1026-1 |  | O7 V((f)) |  |
LAMOST-O 196 | 102.763422 | 2.098965 | LS VI +02 20 |  | O9.2 |  | T
LAMOST-O 197 | 101.225133 | 0.620320 | HD 292 167 |  | O8.5 II((f)) |  |
LAMOST-O 198 | 102.993561 | 1.376179 | HD 289 291 |  | O9.2 III(n) |  |
LAMOST-O 199 | 101.167267 | 0.255560 | TYC 147-1646-1 |  | O9.7 | SB1 | T
LAMOST-O 200 | 101.259080 | 0.224860 | TYC 148-2577-1 |  | O7.5 V |  | T
LAMOST-O 201 | 101.269638 | 0.229797 | Cl* Dolidze 25 MV 17 |  | O7 Vz |  |
LAMOST-O 202 | 101.350887 | 0.229642 | TYC 148-2536-1 |  | O6 V((f)) |  |
LAMOST-O 203 | 102.210323 | 0.377128 | LS VI +00 25 |  | O9.5 V |  |
LAMOST-O 204 | 102.573440 | 0.446564 | HD 292 392 |  | O8.5 Vn |  |
LAMOST-O 205 | 102.181212 | -0.257652 | HD 292 419 |  | O6 Iafp |  | T
LAMOST-O 206 | 103.183444 | -0.187991 | EM* RJHA 83 |  | O9.5 Vne |  | B
LAMOST-O 207 | 102.596035 | -0.540200 | TYC 4800-1443-1 |  | O9.5 V |  | T
LAMOST-O 208 | 101.550781 | -2.914206 | UCAC4 436-021292 |  | O9 V |  | T
LAMOST-O 209 | 99.753638 | -4.380793 | LS VI -04 5 |  | O9.5 V |  | T

Note. — (1) In the last column, ’T’ denotes the new O-type stars found with
LAMOST firstly given in this work, while ’B’ denotes the new ones given in Liu
et al. (2019), Roman-Lopes & Roman-Lopes (2019), Li & Howarth (2020), and Li
(2020); (2) the positions given in this table are LAMOST fiber positions,
which may be not the exact positions of stars with $V<10$ mag, because bright
stars may saturate spectra (Lei et al., 2014). As a compromise, LAMOST fibers
were positioned to their neighbor’s places. The distances between fiber
positions and star positions are given in the fifth column in parseconds, if
any; (3) LAMOST-O 109 is an SB2, which will be published in a future paper.

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