J/ApJS/271/4 Rotational velocities for LAMOST DR9 stars (Zuo+, 2024)
Projected rotational velocities for LAMOST stars with effective temperatures
lower than 9000K.
Zuo F., Luo A.-L., Du B., Li Y., Jones H.R.A., Song Y.-H., Kong X.,
Guo Y.-X.
<Astrophys. J. Suppl. Ser., 271, 4 (2024)>
=2024ApJS..271....4Z 2024ApJS..271....4Z
ADC_Keywords: Spectra, optical; Rotational velocities; Effective temperatures;
Abundances, [Fe/H]
Keywords: Astronomical techniques ; Stellar rotation
Abstract:
In Data Release 9 of LAMOST, we present measurements of vsini for a
total of 121698 stars measured using the Medium Resolution
Spectrograph (MRS) and 80108 stars using the Low Resolution
Spectrograph (LRS). These values were obtained through a χ2
minimization process, comparing LAMOST spectra with corresponding
grids of synthetically broadened spectra. Due to the resolution and
the spectral range of LAMOST, vsini measurements are limited to stars
with an effective temperature (Teff) ranging from 5000 to 8500K for
MRS and 7000 to 9000K for LRS. The detectable vsini for MRS is set
between 27 and 350km/s, and for LRS between 110 and 350km/s. This
limitation is because the convolved reference spectra become less
informative beyond 350km/s. The intrinsic precision of vsini,
determined from multiepoch observations, is approximately ∼4.0km/s for
MRS and ∼10.0km/s for LRS at a signal-to-noise ratio greater than 50.
Our vsini values show consistency with those from APOGEE17, displaying
a scatter of 8.79km/s. They are also in agreement with measurements
from the Gaia DR3 and Sun+ 2021, J/ApJS/257/22 catalogs. An observed
trend in LAMOST MRS data is the decrease in vsini with a drop in Teff,
particularly transiting around 7000K for dwarfs and 6500K for giants,
primarily observed in stars with near-solar abundances.
Description:
Considering the wavelength coverage of the LAMOST DR9 MRS, we selected
stars with 5000K<Teff<8500K to determine vsini from the coadded
spectra. For the low resolving power (LRS; R∼1800), we abandoned the
late-type stars and added a few early-type stars, which are in the
effective temperature range of 7000K<Teff<9000K.
Nonsingle targets were also removed from the selected samples through
crossmatching with Gaia DR3 (I/355), and the
catalogs from Whiting+ (2023, J/AJ/165/193) and
Penoyre+ (2022MNRAS.513.5270P 2022MNRAS.513.5270P).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 74 201806 Parameters of LAMOST LRS & MRS v*sin(i) catalogs
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See also:
III/284 : APOGEE-2 data from DR16 (Johnsson+, 2020)
V/156 : LAMOST DR7 catalogs (Luo+, 2019)
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
J/A+A/331/581 : Rotation and activity in field M dwarfs (Delfosse+ 1998)
J/A+A/393/897 : Rotational velocities of A-type stars II. (Royer+, 2002)
J/A+A/594/A39 : LAMOST-Kepler parameters & activity indicators (Frasca+, 2016)
J/AJ/151/144 : ASPCAP weights for APOGEE chemical elements (Garcia+, 2016)
J/ApJS/244/27 : Radial velocity measurements in LAMOST-II (Wang+, 2019)
J/ApJ/911/138 : Low-mass pre-main-sequence stars in Taurus-Auriga (Nofi+, 2021)
J/ApJS/257/22 : Early-type star stellar rot. in LAMOST MRS. I. (Sun+, 2021)
J/ApJS/259/63 : Chemically peculiar stars CP1 & CP2 from LAMOST (Shang+, 2022)
J/ApJS/259/38 : Ha em.-line stars & Herbig Ae/Be from LAMOST (Zhang+, 2022)
J/AJ/165/193 : ∼30000 Gaia EDR3 nearby accelerating stars (Whiting+, 2023)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- Inst LAMOST spectrograph identifier (1)
5- 19 A15 --- LAMOST LAMOST DR9 unique target identifier (source_id)
21- 31 F11.7 deg RAdeg Right Ascension (J2000)
33- 42 F10.7 deg DEdeg [-10/90] Declination (J2000)
44- 48 I5 --- S/N [4/999]? Signal-to-Noise
50- 53 I4 K Teff [5000/9000] Effective temperature
55- 58 F4.2 [cm/s2] logg [0.09/5] log surface gravity
60- 64 F5.2 [Sun] [Fe/H] [-2.5/1] Metallicity
66- 68 I3 km/s vsini [27/350] Projected rotational velocity
72- 74 I3 km/s e_vsini [0/50]? Uncertainty in vsini
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Note (1): Spectrograph as follows:
LRS = Low Resolution Spectrograph, 3800-9000 Angstroms with R∼1800;
MRS = Medium Resolution Spectrograph,4950-5350 and 6300-6800 Angstroms
with R∼7500.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 23-Apr-2024