J/ApJS/247/9 FGK stars magnetic activity in LAMOST-Kepler field (Zhang+, 2020) ================================================================================ Magnetic activity of F-, G-, and K-type stars in the LAMOST-Kepler field. Zhang J., Bi S., Li Y., Jiang J., Li T., He H., Yu J., Khanna S., Ge Z., Liu K., Tian Z., Wu Y., Zhang X. =2020ApJS..247....9Z ================================================================================ ADC_Keywords: Spectra, optical; Abundances, [Fe/H]; Effective temperatures; Stars, dwarfs; Stars, F-type; Stars, G-type; Stars, K-type Keywords: Stellar activity ; Stellar atmospheres ; Stellar chromospheres ; Stellar magnetic fields Abstract: Monitoring chromospheric and photospheric indexes of magnetic activity can provide valuable information, especially the interaction between different parts of the atmosphere and their response to magnetic fields. We extract chromospheric indexes, S and R_HK_^+^, for 59816 stars from LAMOST spectra in the LAMOST-Kepler program, and photospheric index, Reff, for 5575 stars from Kepler light curves. The log Reff shows positive correlation with logR_HK_^+^. We estimate the power-law indexes between Reff and R_HK_^+^ for F-, G-, and K-type stars, respectively. We also confirm the dependence of both chromospheric and photospheric activity on stellar rotation. Ca ii H and K emissions and photospheric variations generally decrease with increasing rotation periods for stars with rotation periods exceeding a few days. The power-law indexes in exponential decay regimes show different characteristics in the two activity-rotation relations. The updated largest sample including the activity proxies and reported rotation periods provides more information to understand the magnetic activity for cool stars. Description: The LAMOST-Kepler project was initiated to use the LAMOST spectroscopic survey to perform spectroscopic follow-up observations for the targets in the field of the Kepler mission (De Cat+, 2015, J/ApJS/220/19). By 2016 June, this project had collected more than 180,000 optical spectra covering 3700-9000{AA} in low-resolution R~1800. In this work, we selected targets from the LAMOST DR4. We aim at targets of dwarfs, removing giant stars with an empirical Teff-logg relation determined by Ciardi+ (2011AJ....141..108C). Binaries labeled by Berger+ (2018, J/ApJ/866/99) were also excluded. To select F- to K-type stars, we use Teff in the range of 3800-7200K. To place a lower limit on the quality of the individual observations, the S/Ns at the blue end of the spectra are higher than 10. With these constraints, we gathered 86689 spectra for 59816 stars. We cross match 59816 stars with the catalog of McQuillan+ (2014, J/ApJS/211/24) and obtain 5575 targets with both photometric observational data and spectroscopic observational data. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table1.dat 91 5575 Deduced activity proxies of the 5575 stars -------------------------------------------------------------------------------- See also: III/159 : Ca II H and K Measurements Made at MWO (Duncan+ 1991) V/133 : Kepler Input Catalog (Kepler, 2009) V/146 : LAMOST DR1 catalogs (Luo+, 2015) V/153 : LAMOST DR4 catalogs (Luo+, 2018) J/A+A/397/147 : Activity-rotation relationship in stars (Pizzolato+ 2003) J/ApJ/725/875 : Chromospheric activity for CPS stars (Isaacson+, 2010) J/ApJ/743/48 : Stellar rotation periods & X-ray luminosities (Wright+, 2011) J/ApJ/781/124 : Granulation model for 508 KIC stars (Cranmer+, 2014) J/A+A/572/A34 : Pulsating solar-like stars in Kepler (Garcia+, 2014) J/ApJS/211/24 : Rotation periods of Kepler MS stars (McQuillan+, 2014) J/ApJS/220/19 : LAMOST obs. in the Kepler field. I. (De Cat+, 2015) J/MNRAS/448/822 : LAMOST candidate members of star clusters (Xiang+, 2015) J/ApJ/834/207 : Periodicity of Kepler LCs variation (Mehrabi+, 2017) J/ApJ/866/99 : Radii of KIC stars & planets using Gaia DR2 (Berger+, 2018) J/ApJS/241/2 : Ionization profiles of 8 Galactic H II regions (Luisi+, 2019) J/ApJS/243/28 : M star magnetic activities from LAMOST/Kepler (Lu+, 2019) Byte-by-byte Description of file: table1.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 8 I8 --- KIC [1028018/12934451] Kepler Input Catalog ID 10- 16 F7.2 K Teff [3800/6639] Effective temperature (1) 18- 23 F6.2 K e_Teff [53/384] Uncertainty in Teff (1) 25- 28 F4.2 [cm/s2] log(g) [3.5/5.5] log surface gravity (1) 30- 33 F4.2 [cm/s2] e_log(g) [0/0.4] Uncertainty in log(g) (1) 35- 39 F5.2 [Sun] [Fe/H] [-2.8/0.5] Metallicity (1) 41- 44 F4.2 [Sun] e_[Fe/H] [0.06/0.3] Uncertainty in [Fe/H] (1) 46- 51 F6.4 [-] S [0.1/0.9] The S chromospheric index (2) 53- 58 F6.4 [-] e_S [0.0004/0.2] Uncertainty in S 60- 66 F7.4 [-] logR+HK [-7.3/-3.7] log R^+^_HK_ chromospheric index (3) 68- 73 F6.4 [-] e_logR+HK [0.001/0.4] Uncertainty in logR+HK 75- 82 F8.6 [-] Reff [9.8e-5/0.09] Effective photometic variability amplitude (see Section 2.2) 84- 91 F8.6 [-] e_Reff [2e-6/0.02] Uncertainty in Reff -------------------------------------------------------------------------------- Note (1): We use stellar atmospheric parameters (Teff, logg, and [Fe/H]) from the LAMOST Stellar Parameter Pipeline at Peking University (LSP3; Xiang+ 2015MNRAS.448..822X). Note (2): Following Karoff+ (2016NatCo...711058K), we computed the flux ratio S as the emission in the CaII H and K lines relative to the continuum, Equation (1): S=8{alpha}.(H+K)/(R+V) where H and K are the fluxes integrated in 1.09{AA} FWHM triangular windows centered on the line cores of 3968 and 3934{AA}. R and V are the fluxes integrated in 20{AA} rectangular windows centered on 4001{AA} and 3901{AA}. The normalization factor {alpha}=1.8 was adopted from Hall+ (2007AJ....133..862H). The factor of 8 is the ratio of exposure time between HK and RV channels of the Mount Wilson HKP-2 spectrophotometer. For stars with multiple observations, the S values were calculated by the weighted mean values of these multiple spectra. See section 2.1.1. Note (3): Using Mittag+'s method (2013A&A...549A.117M), we calculated the index R_HK_^+^ following Equation (2): R_HK_^+^=(F_HK_-F_HK,phot_-F_HK,basal_)/{sigma}Teff^4^=F_HK_^+^/{sigma}Teff^4^ where Teff is the effective temperature, and {sigma} is the Stefan-Boltzmann constant. Here the HK surface flux is derived from the RV continuum flux and the S index through F_HK_=S.F_RV_/(8{alpha}) (Middelkoop 1982A&A...107...31M). The photospheric flux in the HK bands F_HK,phot_, the basal chromospheric flux F_HK,basal_, and the continuum flux F_RV_ were calculated from the B-V color index (Ramirez & Melendez 2005ApJ...626..465R). See section 2.1.2. -------------------------------------------------------------------------------- History: From electronic version of the journal ================================================================================ (End) Prepared by [AAS], Emmanuelle Perret [CDS] 21-Apr-2020