J/AJ/162/32 LAMOST parameters of Am and non-chemical-peculiar stars (Qin+, 2021)
Rotational velocities of Am and non-chemical-peculiar stars based on Kepler and
LAMOST DR5.
Qin L., Luo A.-L., Hou W., Li Y.-B., Cui K.-M., Zuo F., Zhang S., Wang R.,
Han J.-S., Wang L.-L., Lu Y., Chen X.-L.
<Astron. J., 162, 32-32 (2021)>
=2021AJ....162...32Q 2021AJ....162...32Q (SIMBAD/NED BibCode)
ADC_Keywords: Stars, Am; Stars, ages; Stars, masses; Stars, diameters;
Effective temperatures; Rotational velocities; Optical
Keywords: Chemically peculiar stars
Abstract:
Rotation is a critical physical process operating in the formation of
Am stars. There is a strong correlation between low-velocity rotation
and chemical peculiarity. However, the existence of many
non-chemical-peculiar slow rotators challenges the understanding of Am
stars. The purpose of our work is to search for low-velocity rotating
non-chemical-peculiar A-type stars and Am stars and to make a
comparative analysis. In this paper, we pick out a sample from the
LAMOST-Kepler project, including 21 Am stars, 125
non-chemical-peculiar slow rotators, and 53 non-chemical-peculiar fast
rotators. We calculate the rotational frequencies through a periodic
change of light curves caused by inhomogeneous stellar surfaces and
then obtain the rotational velocities. For slow rotators, the age of
Am stars is statistically younger than that of non-chemical-peculiar
stars in the same temperature bin. In the comparison of the period,
the average amplitude, and stellar mass of Am and
non-chemical-peculiar stars, we discover that there is no difference
in the photometric variability between Am and non-chemical-peculiar
stars, which implies similar inhomogeneities on the surfaces. The
average amplitude of non-chemical-peculiar stars has a downward trend
with the increase of effective temperature and stellar mass, which is
consistent with the theoretical prediction caused by weak
dynamo-generated magnetic fields in A-type stars. In addition, we
confirm four non-chemical-peculiar stars that have flares by checking
field-of-view images, pixel images, and pixel-level light curves.
Description:
The Kepler telescope has continuously observed the Kepler field of
view (FOV) for 4yr, providing high-precision long-term time-series
photometric data. The Large Sky Area Multiobject Fiber Spectroscopic
Telescope is a multifiber large-aperture reflective Schmidt telescope
that can acquire 4000 spectra in one exposure. LAMOST-Kepler project
is a subproject of the Large Sky Area Multi-Object Fibre Spectroscopic
Telescope (LAMOST) Survey and its primary purpose is to obtain as many
spectra as possible in the Kepler FOV and to provide reliable
atmospheric parameters for these stars.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 265 199 The Sample of non-CP stars and Am stars
included in this study
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See also:
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
V/164 : LAMOST DR5 catalogs (Luo+, 2019)
J/ApJS/99/135 : A-type stars rotation and spectral peculiarities (Abt+ 1995)
J/A+A/537/A120 : Rotational velocities of A-type stars. IV. (Zorec+, 2012)
J/MNRAS/431/2240 : Activity in A-type stars from Kepler (Balona, 2013)
J/MNRAS/432/1203 : Rotation periods of M-dwarf stars (McQuillan+, 2013)
J/ApJS/211/24 : Rotation periods of Kepler MS stars (McQuillan+, 2014)
J/AJ/150/133 : Stellar noise 4529 Kepler solar-type dwarfs (Gilliland+, 2015)
J/ApJS/220/19 : LAMOST obs. in the Kepler field. I. (De Cat+, 2015)
J/AJ/151/13 : LAMOST-Kepler MKCLASS spectral classification (Gray+, 2016)
J/AJ/151/68 : Kepler Mission. VII. Eclipsing binaries in DR3 (Kirk+, 2016)
J/MNRAS/467/1830 : Starspots on A stars (Balona, 2017)
J/ApJS/241/29 : Flare catalog through LC data of Kepler DR25 (Yang+, 2019)
J/A+A/640/A40 : 1002 mCP stars from LAMOST DR4 (Hummerich+, 2020)
J/AJ/159/280 : Gaia-Kepler stellar prop. catalog.I. KIC stars (Berger+, 2020)
J/ApJS/249/22 : Radial velocity variable stars from LAMOST DR4 (Tian+, 2020)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 38 A38 --- File File identifier
40- 48 I9 --- LAMOST LAMOST identifier
50- 57 I8 --- KIC Kepler Input Catalog identifier
59- 69 F11.7 deg RAdeg [280/302] Right Ascension in decimal degrees
(J2000)
71- 80 F10.7 deg DEdeg [36/52] Declination in decimal degrees (J2000)
82- 89 F8.6 /d Frot [0.05/2.93] Rotational frequency
91- 98 E8.2 /d e_Frot [6E-7/3E-4] Uncertainty in f
100-106 F7.5 --- VC [0.05/0.66]? Coefficient of variation
108-117 F10.4 umag Amp [72.9/35127] Average light curve amplitude (1)
119-128 F10.4 umag e_Amp [17/17233] Standard deviation in Amp
130-137 F8.4 km/s VRot [5.66/317.8] Rotation velocity
139-145 F7.4 km/s E_VRot [0.1/33] Upper uncertainty in VRot
147-153 F7.4 km/s e_VRot [0.1/27] Lower uncertainty in VRot
155-161 F7.1 K Teff [6067/10963] Effective temperature (2)
163-168 F6.1 K E_Teff [114/1432] Upper uncertainty in Teff
170-175 F6.1 K e_Teff [112/2261] Lower uncertainty in Teff
177-181 F5.3 [cm/s2] logg [3.54/4.43] log surface gravity (2)
183-187 F5.3 [cm/s2] E_logg [0.01/0.3] Upper uncertainty in log(g)
189-193 F5.3 [cm/s2] e_logg [0.02/0.3] Lower uncertainty in log(g)
195-200 F6.3 [Sun] [Fe/H] [-0.6/0.37] Metallicity (2)
202-206 F5.3 [Sun] E_[Fe/H] [0.06/0.2] Upper uncertainty in [Fe/H]
208-212 F5.3 [Sun] e_[Fe/H] [0.09/0.3] Lower uncertainty in [Fe/H]
214-218 F5.3 Msun Mass [1.04/2.75] Mass (2)
220-224 F5.3 Msun E_Mass [0.03/0.4] Upper uncertainty in Mass
226-230 F5.3 Msun e_Mass [0.03/0.6] Lower uncertainty in Mass
232-236 F5.3 Rsun Rad [1.03/4.51] Radius (2)
238-242 F5.3 Rsun E_Rad [0.02/0.97] Upper uncertainty in Radius
244-248 F5.3 Rsun e_Rad [0.02/0.55] Lower uncertainty in Radius
250-253 F4.2 Gyr Age [0.14/3.75] Age (2)
255-258 F4.2 Gyr E_Age [0.05/1.5] Upper uncertainty in Age
260-263 F4.2 Gyr e_Age [0.03/1.2] Lower uncertainty in Age
265 I1 --- Note Additional note (3)
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Note (1): Segmented by period.
Note (2): Taken from the Berger+, 2020, J/AJ/159/280 catalog.
Note (3): Notes as follows:
1 = Am star; 21 occurrences
0 = non-chemical peculiar (CP) star; 178 occurrences
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 12-Nov-2021