J/ApJS/276/44 TIC star magnetic activity with LAMOST DR10 MRS sp. (Su+, 2025)
Magnetic activity of TESS objects observed in the LAMOST Medium-Resolution
Spectral survey.
Su T., Zhang L.-Y., Misra P., Han X.L., Wang Y., Li W., Zhu Z., Pi Q.,
Lu H.
<Astrophys. J. Suppl. Ser., 276, 44 (2025)>
=2025ApJS..276...44S 2025ApJS..276...44S
ADC_Keywords: Spectra, red; Photometry; Radial velocities; Abundances, [Fe/H];
Equivalent widths; Stars, diameters; Stars, masses; Stars, flare
Keywords: Stellar activity ; Stellar chromospheres ; Stellar flares
Abstract:
A combination of spectroscopic and photometric observations provides
an excellent data sample for studying stellar chromospheric activity.
We have combined LAMOST medium-resolution spectra with TESS 2 minute
light curves and extracted over 530,000 spectra and 110,000 light
curves from more than 40,000 stars. We have quantified the Hα
line intensity in each spectrum and found that 38,659 spectra from
7002 stars exhibited excess Hα emission and that the intensity
of stellar chromospheric activity increases with later spectral types.
We also discovered that the boundary value between the saturated and
unsaturated regions of chromospheric activity for different spectral
type stars is around Ro=0.1. By analyzing the TESS light curves, we
identified 31,539 flare events from 4120 stars. Through these flare
events, we determined that the flare-frequency proportion of stars
increases with later spectral types. We have found that the power-law
index of the flare-frequency distribution for F-, G-, K-, and M-type
stars is around 2.0, while that for A-type stars is 1.3. Additionally,
we observed that the amplitude of brightness variations caused by
modulation due to starspot coverage (Reff) is positively correlated
with both the flare intensity and intensity of chromospheric activity
and that the chromospheric activity was generally stronger in flare
stars as compared to nonflare stars. We also found that within 300pc,
the proportion of chromospherically active stars and flare stars
decreases with increasing distance from the Galactic disk. Finally, we
discovered six flare events from the Hα variation and estimated
their energies.
Description:
LAMOST is an approximately 4m aperture Schmidt telescope located in
Xinglong, China. As of the release of LAMOST DR10 data, LAMOST has
obtained a total of 10,486,216 medium-resolution spectra. LAMOST
medium-resolution spectral survey data have a resolution of
approximately 7500. The observed wavelength ranges from 4900 to 5400Å
and from 6300 to 6800Å. In this paper, we use the Hα spectral
line (central wavelength 6562.8Å) as the chromospheric activity
indicator to study stellar chromospheric activity.
By crossmatching the medium-resolution data from LAMOST DR10 with the
2 minute light-curve data from TESS, we obtained over 539,000 red-band
spectra (6300-6800{AA) in total.
Through crossmatching with LAMOST DR10 data, we have obtained a total
of over 116,000 2 minute light curves from the first 74 sectors of
TESS (2018-Jul-25 to 2024-Jan-30).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 190 540181 Parameters of stellar atmospheres and chromospheric
activity quantified based on medium-resolution
spectra from LAMOST DR10 for 51451 sources
table2.dat 79 36267 Parameters of 31,539 flare events from TESS survey
for 4354 TIC stars
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See also:
B/vsx : AAVSO International Variable Star Index VSX (Watson+, 2006-)
IV/38 : TESS Input Catalog - v8.0 (TIC-8) (Stassun+, 2019)
V/156 : LAMOST DR7 catalogs (Luo+, 2019)
IV/39 : TESS Input Catalog version 8.2 (TIC v8.2) (Paegert+, 2021)
I/357 : Gaia DR3 Part 3. Non-single stars (Gaia Collaboration, 2022)
J/ApJS/85/315 : F, G and K dwarf stars of the Pleiades (Soderblom+ 1993)
J/A+A/327/1039 : Structure and evolution of low-mass stars (Chabrier+ 1997)
J/A+A/337/403 : Low-mass stars evolutionary models (Baraffe+ 1998)
J/A+A/331/581 : Rotation and activity in field M dwarfs (Delfosse+ 1998)
J/A+AS/146/103 : CaII H&K to CaII IRT echelle spectra (Montes+, 2000)
J/AJ/123/3356 : Palomar/MSU nearby star sp. survey. III. (Gizis+, 2002)
J/A+A/397/147 : Activity-rotation relationship in stars (Pizzolato+ 2003)
J/AJ/128/426 : Subdwarfs in the SDSS (West+, 2004)
J/ApJ/687/1264 : Age estimation for solar-type dwarfs (Mamajek+, 2008)
J/AJ/135/785 : SDSS-DR5 low-mass star spectroscopic sample (West+, 2008)
J/other/A+ARV/17.251 : Stars observed with Doppler imaging (Strassmeier, 2009)
J/MNRAS/407/465 : Fast-rotating M dwarfs in NGC2516 (Jackson+, 2010)
J/ApJ/743/48 : Stars with rot. periods & X-ray luminosities (Wright+, 2011)
J/other/Nat/485.478 : Superflares on solar-type stars (Maehara+, 2012)
J/ApJS/209/5 : Superflares of Kepler stars. I. (Shibayama+, 2013)
J/ApJ/795/161 : Activity & rotation in Praesepe & Hyades (Douglas+, 2014)
J/MNRAS/447/2714 : Flare stars across the H-R diagram (Balona+, 2015)
J/ApJ/809/77 : Transiting Exoplanet Survey Satellite (Sullivan+, 2015)
J/ApJ/829/23 : Stellar flares from Q0-Q17 Kepler LCs (Davenport, 2016)
J/A+A/594/A39 : LAMOST-Kepler param. and activity indicators (Frasca+, 2016)
J/ApJ/851/91 : Stat. studies of solar white-light flares (Namekata+, 2017)
J/ApJ/834/85 : Hα emission in nearby M dwarfs (Newton+, 2017)
J/ApJ/849/36 : Flaring activity of M dwarfs in Kepler (Yang+, 2017)
J/MNRAS/476/908 : Chromospheric activity in 4 open clusters (Fang+, 2018)
J/ApJS/243/28 : Magnetic activities from LAMOST & Kepler (Lu+, 2019)
J/ApJS/241/29 : Flare catalog through LC data of Kepler DR25 (Yang+, 2019)
J/AJ/159/60 : Flares from stars in TESS sectors 1 & 2 (Gunther+, 2020)
J/ApJ/890/46 : Superflares on solar-type stars from TESS 1st yr (Tu+, 2020)
J/ApJ/891/23 : Stellar abundances from LAMOST MRS (SPCAnet) (Wang+, 2020)
J/ApJS/247/9 : FGK stars magnetic activity in LAMOST-Kepler (Zhang+, 2020)
J/ApJS/253/19 : Halpha and other EWs of LAMOST M-type stars (Zhang+, 2021)
J/ApJ/926/204 : TESS campaign of low-mass flare stars (Howard+, 2022)
J/ApJS/258/16 : TESS Eclipsing Binary stars. I. Sectors 1-26 (Prsa+, 2022)
J/A+A/662/A41 : Magnetic fields in 292 M dwarfs. (Reiners+, 2022)
J/ApJS/261/26 : Host stars from LAMOST, TESS, Kepler & K2 (Su+, 2022)
J/ApJS/268/4 : Stellar var. with TESS 2min cadence phot. (Fetherolf+, 2023)
J/MNRAS/522/29 : 15000 ellipsoidal binary candidates in TESS (Green+, 2023)
J/A+A/669/A15 : TESS flare events and physical parameters (Yang+, 2023)
J/ApJS/264/17 : Sp. data of TESS objects with LAMOST (Zhang+, 2023)
J/ApJS/271/60 : Magnetic activity of stars from LAMOST & TESS (Su+, 2024)
http://www.lamost.org/dr10/v1.0/ : LAMOST DR10 homepage
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- LAMOST LAMOST identifier (JHHMMSS.ss+DDMMSS.s)
21- 31 F11.5 d HJD [58024.8/59737.12]? Heliocentric Julian Date;
HJD-2400000
33- 37 F5.1 --- SNR [0/999] Signal-to-noise ratio of r band
39- 46 F8.2 mag Gmag [2.27/21.02]?=-9999 Gaia DR3 G-band apparent
magnitude
48- 52 F5.2 mag Bp-Rp [-0.56/6.47]? Gaia (blue-red) passband color
54- 60 F7.2 km/s RVel [-601/604.5]? Radial velocity
62- 66 F5.2 km/s e_RVel [0.25/20.4]? Uncertainty in RVel
68- 74 F7.1 K Teff [2804/70000]? Effective temperature
76- 82 F7.1 K e_Teff [3/24300]? Uncertainty in Teff
84- 88 F5.3 [cm/s2] logg [3.1/6.4]? Log surface gravity
90- 94 F5.3 [cm/s2] e_logg [0/0.6]? Uncertainty in log (g)
96- 101 F6.3 [Sun] [Fe/H] [-2.8/0.86]? Metallicity
103- 107 F5.3 [Sun] e_[Fe/H] [0.003/0.31]? Uncertainty in [Fe/H]
109- 117 F9.3 0.1nm EW [-3593.4/13405.7]? Hα equivalent width;
Angstroms
119- 126 F8.3 0.1nm e_EW [0/6809]? Uncertainty in EW
128- 133 F6.3 0.1nm EWp [-5.7/17.17]? Excess Hα chromospheric
emission; Angstroms (EWp=EW-EWbasal)
135- 143 F9.6 --- Rp [-0.0005/0.002]? Ratio of Hα
luminosity to stellar radiative luminosity
145- 152 F8.5 d Prot [0.3/13.3]? Rotational period
154- 159 F6.2 Rsun Rad [0.07/508]? Stellar radius
161- 164 F4.2 Rsun e_Rad [0/1.5]? Uncertainty in Rad
166- 169 F4.2 Msun Mass [0.09/3.2]? Stellar mass
171- 174 F4.2 Msun e_Mass [0.01/0.7]? Uncertainty in Mass
176- 182 F7.5 --- Ro [0.0023/2.47]? Rossby number
184- 190 F7.5 --- Reff [8e-05/6.3]? Amplitude of brightness
variations caused by modulation due to
starspot coverage
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 I10 --- TIC [1153082/2045772593] TESS identifier
12- 22 F11.6 d Peak [1386.27/3339.3] Modified HJD of peak time of
flare event
24- 34 F11.6 d Start [1386.26/3339.3] Modified HJD of flare event start
36- 46 F11.6 d End [1386.28/3339.31] Modified HJD of flare event end
48- 53 F6.4 h Dur [0.13/7.1] Duration of flare event
55- 62 F8.6 --- Amp [0.00026/4] Amplitude of flare event
64- 68 F5.2 mag Tmag [1.37/18.53]? TESS apparent magnitude
70- 77 E8.2 10-7J Eng [1.42e+31/2.09e+38]? Energy; erg
79- 79 A1 --- Rej Visual flare event inspection code (Y=flare event;
N=flare misidentified by the code)
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 29-Oct-2025