J/ApJS/272/43 Am and Ap star candidates from LAMOST DR10 (Yang+, 2024)
A sample of Am and Ap candidates from LAMOST DR10 (v1.0) based on the ensemble
regression model.
Yang H.-F., Wang R., Cai J.-H., Luo A.-L., Du B., He Y.-T., Su M.-H.,
Shi C.-H., Zhao X.-J., Xun Y.-L., Yuan Y.-N.
<Astrophys. J. Suppl. Ser., 272, 43 (2024)>
=2024ApJS..272...43Y 2024ApJS..272...43Y
ADC_Keywords: Stars, peculiar; Stars, Am; Stars, Ap; Spectral types;
Abundances, [Fe/H]; Magnitudes; Spectra, optical; Surveys
Keywords: Chemically peculiar stars ; Am stars ; Ap stars
Abstract:
Large samples of Am and Ap stars are helpful in studying the interplay
between phenomena like atomic diffusion, magnetic fields, and stellar
rotation in stellar astrophysics. Existing samples of Am and Ap stars,
mostly obtained from spectral data with a signal-to-noise ratio in the
g band (S/Ng) greater than 50, can benefit from expansion by exploring
spectra with lower S/Ng. Therefore, this paper proposes an ensemble
regression model applicable to spectra with a minimum S/Ng of 30.
Using the model, we identify 21361 Am candidates, of which 11614 are
new, and 6182 Ap candidates, of which 4978 are new, from LAMOST DR10.
The Am sample size has increased by 60% and the Ap sample size has
increased by 180% compared to the previous sample. In terms of
effective temperature (Teff), the Am candidates range mainly from 6000
to 8500K, while the Ap candidates range from 6000 to 11700K. The
surface gravity (logg) distributions for Am and Ap candidates differ
in the range of 3.25-4.75dex. The number of Am candidates increases
stepwise, in contrast to the relatively uniform distribution of Ap
candidates across the entire surface gravity range. Regarding
metallicity ([Fe/H]), Am candidates typically range from -0.75 to
0.38dex, peaking near 0dex, while Ap candidates are distributed from
-1.38 to 0.38dex, with a peak near -0.5dex.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table8.dat 290 27543 The catalogs of Am and Ap candidates in the
LAMOST Dr10 (v1.0)
--------------------------------------------------------------------------------
See also:
III/260 : General Catalogue of Ap and Am stars (Renson+ 2009)
V/156 : LAMOST DR7 catalogs (Luo+, 2019)
IV/39 : TESS Input Catalog version 8.2 (TIC v8.2) (Paegert+, 2021)
I/354 : StarHorse2, Gaia EDR3 photo-astrometric distances (Anders+, 2022)
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
J/A+A/475/1053 : Magnetic fields in Ap/Bp stars (Auriere+, 2007)
J/A+A/499/567 : BV differential photometry of HR 7224 (Krticka+, 2009)
J/MNRAS/449/1401 : Am stars candidates from LAMOST DR1 (Hou+, 2015)
J/AJ/151/13 : LAMOST-Kepler MKCLASS spectral classification (Gray+, 2016)
J/MNRAS/480/2953 : Catalogue of CP stars (HgMn, ApBp, AmFm) (Ghazaryan+, 2018)
J/ApJS/242/13 : Am stars from LAMOST DR5 (Qin+, 2019)
J/MNRAS/487/4695 : Rotationally variable A stars from TESS (Sikora+, 2019)
J/MNRAS/496/832 : The SDSS/APOGEE catalogue of HgMn stars (Chojnowski+, 2020)
J/A+A/640/A40 : 1002 mCP stars from LAMOST DR4 (Hummerich+, 2020)
J/A+A/645/A34 : LAMOST DR4 New mercury-manganese stars (Paunzen+, 2021)
J/ApJS/259/63 : Chemically peculiar stars from LAMOST (Shang+, 2022)
J/ApJS/266/14 : Am stars selected in LAMOST DR8-DR10 (Tian+, 2023)
Byte-by-byte Description of file: table8.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 I5 --- Seq [1/27543] Internal index number
7- 16 I10 --- ObsID [703238/1017907053] LAMOST unique identifier
of the spectrum
18- 27 F10.6 deg RAdeg Right Ascension in decimal degrees (J2000)
29- 37 F9.6 deg DEdeg Declination in decimal degrees (J2000)
39- 44 F6.2 --- SNRg [30/999] Signal-to-Noise of LAMOST spectrum
in g band
46- 47 A2 --- SpT-LA LAMOST spectral type
49- 53 F5.3 [cm/s2] logg [3.25/4.75] LAMOST log surface gravity
55- 59 F5.3 [cm/s2] e_logg [0.08/0.41] Uncertainty in log (g)
61- 67 F7.1 K Teff [6000/20000] LAMOST effective temperature
69- 75 F7.2 K e_Teff [126/1495] Uncertainty in Teff
77- 82 F6.3 [Sun] [Fe/H] [-1.4/0.4] LAMOST log Fe/H number abundance
84- 88 F5.3 [Sun] e_[Fe/H] [0.05/0.3] Flag on [Fe/H]
90- 98 F9.6 mag Gmag [5.24/20.85]? Gaia DR3 G band magnitude
100- 107 F8.6 mag e_Gmag [0.0027/0.07]? Uncertainty in Gmag
109- 132 A24 --- SpT-MK MKCLASS code spectral type
134- 138 A5 --- q_SpT-MK Quality flag for SpT-MK if any
(from "poor" to "excel")
140- 147 F8.6 --- RFactor [0.9/0.993] Reliability factor;
see Section 2.3
149- 150 A2 --- Type Star type ("Am"=21361 occurrences
or "Ap"=6182 occurrences)
151 A1 --- n_Type [*] *=new star type (1)
153- 160 A8 --- --- [Gaia DR3]
162- 180 I19 --- GaiaDR3 ? Gaia DR3 identifier
182- 188 F7.1 K Teff-G [3290/18757]? Gaia DR3 effective temperature
190- 196 F7.1 K b_Teff-G [3288/18433]? Lower boundary in Teff-G
198- 204 F7.1 K B_Teff-G [3291/18912]? Upper boundary in Teff-G
206- 211 F6.4 [cm/s2] logg-G [1.59/5.07]? Gaia DR3 log surface gravity
213- 218 F6.4 [cm/s2] b_logg-G [1.58/5.06]? Lower boundary in log(g)-G
220- 225 F6.4 [cm/s2] B_logg-G [1.6/5.08]? Upper boundary in log(g)-G
227- 233 F7.4 [Sun] [Fe/H]-G [-4.15/0.8]? Gaia DR3 log Fe/H number
abundance
235- 241 F7.4 [Sun] b_[Fe/H]-G [-4.15/0.8]? Lower boundary in [Fe/H]-G
243- 249 F7.4 [Sun] B_[Fe/H]-G [-4.15/0.8]? Upper boundary in [Fe/H]-G
251- 257 F7.1 K Teff-L [4079/19326]? LASP effective temperature
259- 264 F6.2 K e_Teff-L [6/630]? Uncertainty in Teff-L
266- 271 F6.3 [cm/s2] logg-L [-0.2/4.9]? LASP log surface gravity
273- 277 F5.3 [cm/s2] e_logg-L [0.007/0.8]? Uncertainty in log(g)-L
279- 284 F6.3 [Sun] [Fe/H]-L [-2.5/1]? LASP log Fe/H number abundance
286- 290 F5.3 [Sun] e_[Fe/H]-L [0.003/0.9]? Uncertainty in [Fe/H]-L
--------------------------------------------------------------------------------
Note (1): The data without asterisks represent candidates obtained by us that
are related to the star catalog provided by Shang+ 2022, J/ApJS/259/63
("the old candidates"), while asterisks flag new candidates.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 29-Aug-2024