J/ApJS/281/39 Active young stars in LAMOST-Kepler (Xu+, 2025)
Active young stars in the LAMOST-Kepler survey.
Xu F., Gu S., Xiang Y.
<Astrophys. J. Suppl. Ser., 281, 39 (2025)>
=2025ApJS..281...39X 2025ApJS..281...39X
ADC_Keywords: Stars, pre-main sequence; Abundances, [Fe/H]; Radial velocities;
Magnitudes, absolute; Equivalent widths; Spectra, optical;
Photometry; Stars, variable
Keywords: Stellar activity ; Stellar accretion ; Pre-main sequence ;
Zero-age main sequence stars
Abstract:
In the early stages of their lives, young stars harbor diverse
processes exhibiting strong signatures, making them ideal targets for
investigating stellar accretion, dynamo actions, and exoplanet
formation. However, the current samples of active stars are highly
limited in both number and parameter space, suffering from significant
statistical uncertainties. By simultaneously measuring the activity
proxy, the Balmer Hα6563Å line emission, and the youth
indicator, the lithium 6708Å line, with the Large Sky Area
Multi-Object Fiber Spectroscopic Telescope (LAMOST) spectra, we have
identified more than 1000 candidates of active young stars (aYSs) with
Teff≤7000K and logg≥3.5 in the Kepler prime field. Then we matched
660 stars with the Kepler light curves, and determined their periods
and variable types. Based on these light curves, we are left with
78 dubious and 52 stable stars, and we have identified 22 eclipsing
binaries, 3 heartbeat binaries, 1 transiting exoplanetary system
candidate, 13 long-period variables, 61 pulsating stars, 18 irregular
variables, 57 T Tauri stars, 173 flaring stars, and 435 rotational
variables (the numbers are not exclusive). Supplementing the
cluster-based samples, this sample has a broader parameter space
coverage. This work will be beneficial for identifying aYSs in much
larger datasets, such as the one produced by crossmatching between the
LAMOST and Transiting Exoplanet Survey Satellite surveys, and the
future survey conducted by the Chinese Space Station Survey Telescope.
Description:
We utilize spectra from the LAMOST low-resolution spectroscopic survey
(LRS) data releases (DR) 5 and 11 and medium-resolution spectroscopic
survey (MRS) DR11 for the Kepler prime field in the ranges of
RAJ2000=277.5°-304.5° and DEJ2000=34°-53°. The LRS
spectra have a resolution of R∼1800 and a wavelength range of
3700-9000Å. The MRS spectra have a resolution of R∼7500 and
wavelength ranges of 4950-5350 and 6300-6800Å. The DR5 corresponds
to the survey Phase I (2011 Oct-2017 Jun), while the DR11 also
contains data acquired in the survey Phase II (2017 Sep-2023 Jun). In
the downloaded data, about 17.5% targets in the DR5 are absent from
the DR11.
We also use the matched light curves (LCs) from the space-based Kepler
survey, which provides high-precision photometry on more than one
million stars from 2009 to 2013.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 370 182818 Input catalogue
table2.dat 132 1714 Final catalogue of identified active young star
(aYS) candidates
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See also:
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
V/164 : LAMOST DR5 catalogs (Luo+, 2019)
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
V/162 : LAMOST DR11 catalogs (Luo+, 2026)
J/MNRAS/358/13 : Faint dwarfs in NGC 2547 (Jeffries+, 2005)
J/other/A+ARV/17.251 : Stars observed with Doppler imaging (Strassmeier, 2009)
J/AJ/142/112 : KIC photometric calibration (Brown+, 2011)
J/MNRAS/432/1203 : Rotation periods of M-dwarf stars (McQuillan+, 2013)
J/ApJS/211/2 : Revised properties of Q1-16 Kepler targets (Huber+, 2014)
J/A+A/575/A57 : LQ Hya activity and Li variations (Flores Soriano+, 2015)
J/A+A/591/A43 : Differential rotation in solar-like stars (Distefano+, 2016)
J/ApJS/235/38 : Kepler planet cand. VIII. DR25 reliability (Thompson+, 2018)
J/ApJ/902/114 : Stellar activity. I. Chandra, Gaia & GALEX (Wang+, 2020)
J/ApJS/260/45 : Stellar param. of M-type stars from LAMOST DR8 (Ding+, 2022)
J/A+A/664/A78 : Kepler targets class based on LAMOST spectra (Frasca+, 2022)
J/ApJ/936/23 : Young stellar objects Gaia EDR3 properties (Wang+, 2022)
J/MNRAS/514/4781 : Active stars in the LAMOST-K2 field (Xiang+, 2022)
J/ApJS/266/28 : Orbital parameters of Kepler heartbeat stars (Li+, 2023)
J/ApJS/271/58 : Lithium abundances from LAMOST MRS DR9 spectra (Ding+, 2024)
J/A+A/685/A83 : Members for 41 open clusters (Gutierrez Albarran+, 2024)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- RS LAMOST spectroscopic survey release (G1)
5- 23 A19 --- LAMOST LAMOST target ID designation
(JHHMMSS.ss+DDMMSS.s)
25- 32 I8 --- KIC [43465/13154091]? Kepler identifier
34- 44 F11.7 deg RAdeg [277.5/304.5] Right Ascension, LAMOST (J2000)
46- 55 F10.7 deg DEdeg [34/53] Declination, LAMOST (J2000)
57- 66 I10 --- ObsID [52101002/1128116245] LAMOST unique
observation ID
68- 72 I5 --- SNR [0/999]?=-9999 Spectral signal to noise (2)
74- 80 F7.2 K Teff [3012/7000] Surface effective temperature,
assembled (3)
82- 87 F6.2 K e_Teff [3/999]? Uncertainty in Teff
89- 93 F5.3 [cm/s2] logg [3.5/5.9] Log, surface gravity, assembled (3)
95- 99 F5.3 [cm/s2] e_logg [0.002/1.2]? Uncertainty in logg
101- 106 F6.3 [-] FeH [-2.68/1]? Metallicity, assembled (3)
108- 112 F5.3 [-] e_FeH [0.003/1]? Uncertainty in FeH
114- 120 F7.2 km/s RV [-378/422]? Radial velocity, assembled or
derived (3)
122- 127 F6.2 km/s e_RV [0/172]? Uncertainty in RV
129- 136 A8 --- --- [Gaia DR3]
138- 156 I19 --- GaiaDR3 ? Gaia DR3 source ID
158- 166 F9.6 mag GMag [-8.3/11.7]? Gaia absolute Gmag
168- 176 F9.6 mag BP-RP [-0.41/2.9]? Gaia color index, GBP-GRP
178- 185 F8.6 --- RMScont [0.0018/2.5]? RMS noise, reference
continuum (4)
187- 193 F7.3 0.1nm EWNeb [-10.32/56.4]? Equivalent width of nebular
line (5)
195- 204 F10.6 0.1nm EWHaI [-16.4/118.2]? Integral, equivalent width,
Hα (6)
206- 214 F9.6 0.1nm e_EWHaI [0.0049/11.2]? Uncertainty in EWHaI, Eq. 3
216- 224 F9.6 --- AmpHa [0/10]? Gaussian fitted amplitude, Hα
(7)
226- 234 F9.6 --- SigHa [0.15/10]? Gaussian fitted sigma, Hα
(7)
236- 243 F8.6 --- RMSHa [0.002/3.2]? RMS of Gaussian fitted
residuals, Hα (7)
245- 254 F10.6 0.1nm EWHaG [0/162.1]? Gaussian fit equivalent width,
Hα (8)
256- 264 F9.6 0.1nm e_EWHaG [0.0005/2.1]? Uncertainty in EWHaG, Eq. 4
266- 275 F10.6 0.1nm EWHa [-8.2/140.1]? Final equivalent width,
Hα, Equation 1
277- 284 F8.6 0.1nm e_EWHa [0.003/5.6]? Uncertainty in HaEW, Equation 2
286- 294 F9.6 0.1nm EWLiI [-7.2/12.3]? Integral, equivalent width, Li
(6)(7)
296- 303 F8.6 0.1nm e_EWLiI [0.003/5.7]? Uncertainty in EWLiI,
Equation 3
305- 313 F9.6 --- AmpLi [-1.7/0.7]? Gaussian fitted amplitude, Li
(6)(8)
315- 322 F8.6 --- SigLi [0.15/3.5]? Gaussian fitted sigma, Li (8)
324- 331 F8.6 --- RMSLi [0.001/5.2]? RMS of Gaussian fitted
residuals, Li (8)
333- 341 F9.6 0.1nm EWLiG [-8.5/2.7]? Gaussian fit equivalent width,
Li (6)(9)
343- 351 F9.6 0.1nm e_EWLiG [0.0006/3.1]? Uncertainty in EWLiG,
Equation 4
353- 361 F9.6 0.1nm EWLi [-6.2/7.9]? Final equivalent width, Li,
Equation 1 (6)
363- 370 F8.6 0.1nm e_EWLi [0.002/3]? Uncertainty in EWLi, Equation 2
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Note (2): SNRR in the LRS spectra or SNR in the MRS spectra.
Note (3): Values assembled from literature or archive sources as
listed in Section 2.1.
For some RV, derived following Fang+ 2016MNRAS.463.2494F 2016MNRAS.463.2494F
Note (4): RMS measured in wavelength ranges of 6380-6450Å 6630-6700Å
Note (5): Measured by an integral over a wavelength width of 4Å
around 6548, 6583, 6716 and 6731Å, respectively.
Note (6): Values of LiEW were converted to positive values for easy
comparisons.
Note (7): Integrated equivalent width over 5Å around Hα and 3Å
around Li line centers.
Note (8): For Gaussian fitting we required 0≤HaGA≤10, 1≤HaGsgm≤10,
-1.0≤LiGA≤0, 1.0≤LiGsgm≤ 3.5. Edge values, e.g., HaGA≃0.00000,
indicate that the Gaussian fitting was poorly converged.
Note (9): Gaussian-fit equivalent widths over segments 6545-6581Å and
6695-6721Å for the Hα and Li lines, respectively.
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Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- RS LAMOST spectroscopic survey release (G1)
5- 23 A19 --- LAMOST LAMOST target ID designation
(JHHMMSS.ss+DDMMSS.s)
25- 34 I10 --- ObsID [52104082/1128115131] LAMOST unique
observation ID
36- 43 I8 --- KIC [1028018/12835007]? Kepler identifier
45- 53 F9.6 0.1nm EWHa [0.017/10.5] Final Halpha equivalent width,
Equation 1
55- 62 F8.6 0.1nm e_EWHa [0.004/0.5] Uncertainty in EWHa
64- 71 F8.6 0.1nm EWLi [0.007/1.8] Final Li equivalent width, Eq. 1
73- 80 F8.6 0.1nm e_EWLi [0.002/0.1] Uncertainty in EWLi
82- 90 F9.6 d Per [0.1/90]? Dominant Period
92- 99 F8.6 d e_Per [0.0003/2.7]? Uncertainty in Per
101-109 F9.6 d Porb [0.49/71.8]? Orbital Period
111-118 F8.6 d e_Porb [0.003/0.4]? Uncertainty in Porb
120-132 A13 --- Type Variable Type (2)
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Note (2): "+" means multiple types; "|" means indistinguishable types.
Variability types as:
D = Dubious or non-variable object, showing ambiguity;
EB = Eclipsing binary, normally showing V-shape primary and
secondary eclipses;
EP = Transiting exoplanetary system candidate, showing a
U-shape/flat-bottom eclipse;
FL = Flaring star, identified by occasional flares which
usually show rapid rising phases following by slow
long-lasting decay phases;
HB = Heartbeat binary (3 occurrences)
IR = Irregular variable with non-periodic variability;
LP = Long-period variable, varying in a timescale of tens of days;
N = Dubious or non-variable object, showing no variability;
PUL = Pulsating star, distinguished by sawtooth or sinusoidal
shape in its LC;
ROT = Rotational variable due to its starspot RM effect;
TTS = T-Tauri star.
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Global notes:
Note (G1): Resolution survey as follows:
LRS = LAMOST low-resolution spectroscopic survey DR5 or DR11
MRS = LAMOST medium-resolution spectroscopic survey DR11 (18968 occurrences)
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History:
From electronic version of the journal
License: CC-BY-4.0
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 26-Jun-2026