J/ApJ/906/72 2344 superflares on 266 solar-type stars (Okamoto+, 2021)
Statistical Properties of Superflares on Solar-type Stars; Results Using All of
the Kepler Primary Mission Data.
Okamoto S., Notsu Y., Maehara H., Namekata K., Honda S., Ikuta K.,
Nogami D., Shibata K.
<Astrophys. J., 906, 72 (2021)>
=2021ApJ...906...72O 2021ApJ...906...72O
ADC_Keywords: Stars, G-type; Stars, flare; Optical; Effective temperatures;
Stars, diameters
Keywords: Flare stars ; Optical flares ; Stellar flares ; G dwarf stars ;
G stars
Abstract:
We report the latest statistical analyses of superflares on solar-type
(G-type main-sequence; effective temperature is 5100-6000K) stars
using all of the Kepler primary mission data and Gaia Data Release 2
catalog. We updated the flare detection method from our previous
studies by using a high-pass filter to remove rotational variations
caused by starspots. We also examined the sample biases on the
frequency of superflares, taking into account gyrochronology and flare
detection completeness. The sample sizes of solar-type and Sun-like
stars (effective temperature is 5600-6000K and rotation period is over
20 days in solar-type stars) are ∼4 and ∼12 times, respectively,
compared with Notsu et al. As a result, we found 2341 superflares on
265 solar-type stars and 26 superflares on 15 Sun-like stars; the
former increased from 527 to 2341 and the latter from three to 26
events compared with our previous study. This enabled us to have a
more well-established view on the statistical properties of
superflares. The observed upper limit of the flare energy decreases as
the rotation period increases in solar-type stars. The frequency of
superflares decreases as the stellar rotation period increases. The
maximum energy we found on Sun-like stars is 4x1034erg. Our analysis
of Sun-like stars suggests that the Sun can cause superflares with
energies of ∼7x1033erg (∼X700-class flares) and ∼1x1034erg
(∼X1000-class flares) once every ∼3000 and ∼6000yr, respectively.
Description:
We searched for superflares using the Kepler 30 minute (long) time
cadence data that were taken from 2009 May to 2013 May (quarters
0-17). We retrieved the data of the Kepler Date Release 25 (DR25)
from the Multimission Archive at the Space Telescope (MAST) We
detected 2344 superflares on 266 solar-type stars from Kepler 30
minute (long) time cadence data of ∼4yr.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 96 2344 Parameters of superflares on solar-type stars
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See also:
J/ApJS/159/141 : Spectroscopic properties of cool stars. I. (Valenti+, 2005)
J/ApJ/687/1264 : Age estimation for solar-type dwarfs (Mamajek+, 2008)
J/AJ/142/112 : KIC photometric calibration (Brown+, 2011)
J/ApJ/743/48 : Stars rotation periods and X-ray luminosities (Wright+, 2011)
J/other/Nat/485.478 : Superflares on solar-type stars (Maehara+, 2012)
J/ApJS/199/30 : Effective temperature scale for KICstars (Pinsonneault+, 2012)
J/ApJS/209/5 : Superflares of Kepler stars. I. (Shibayama+, 2013)
J/ApJS/211/24 : Rotation periods of Kepler MS stars (McQuillan+, 2014)
J/MNRAS/447/2714 : Flare stars across the H-R diagram (Balona+, 2015)
J/A+A/581/A28 : Stellar X-ray flares from the 2XMM catalog (Pye+, 2015)
J/ApJ/829/23 : Stellar flares from Q0-Q17 Kepler LCs (Davenport, 2016)
J/ApJS/224/37 : White-light flares on close binaries from Kepler (Gao+, 2016)
J/MNRAS/472/1618 : Kepler study of starspot lifetimes (Giles+, 2017)
J/ApJS/229/30 : Stellar properties of Q1-17 Kepler targets (Mathur+, 2017)
J/ApJ/851/91 : Statistical studies solar white-light flares (Namekata+, 2017)
J/ApJS/232/26 : Catalog of Kepler flare stars (Van Doorsselaere+, 2017)
J/ApJ/849/36 : Flaring activity of M dwarfs in the Kepler field (Yang+, 2017)
J/ApJ/866/99 : Radii of KIC stars & planets using Gaia DR2 (Berger+, 2018)
J/ApJ/883/88 : Short-duration stellar flares GALEX & Kepler (Brasseur+, 2019)
J/ApJ/871/187 : Spot parameters on KIC solar-type stars (Namekata+, 2019)
J/AJ/159/60 : 8695 flares 1228 stars in TESS sectors 1 & 2 (Gunther+, 2020)
J/ApJ/890/46 : Superflares solar-type stars from TESS first year (Tu+, 2020)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 8 I8 --- KIC Kepler Input Catalog identifier
10- 13 I4 K Teff [5102/5988] Effective temperature (1)
15- 17 I3 K e_Teff [105/210] Uncertainty in Teff (1)
19- 23 F5.3 Rsun Rstar [0.49/1.53] Stellar radius (1)
25- 29 F5.3 Rsun E_Rstar [0.03/0.2] Upper uncertainty in Rstar (1)
31- 35 F5.3 Rsun e_Rstar [0.03/0.2] Lower uncertainty in Rstar (1)
37- 42 F6.3 d Prot [0.24/40.1] Rotation period (2)
44- 48 F5.3 d e_Prot [0/9] Error in Prot (2)
50- 57 F8.2 10-6 Amp [1210/95065] Average variability amplitude within
1 period (2)
59- 64 F6.3 mag Kemag [9.91/16.1] Kepler band magnitude (3)
66- 72 E7.1 Rsun2 Aspot [0.0008/0.13] Area of the starspots, 2πxRsun2
74- 81 F8.2 d Date [54954/56424] Date of flare peak; BJD-2400000
83- 86 F4.2 d Dur [0.04/0.33] Duration of flare
88- 94 E7.1 10-7J E [4.2e+32/9.6e+35] Bolometric flare energy, ergs
96- 96 A1 --- Flag Suspicious flag (4)
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Note (1): Derived from Gaia-DR2 in Berger+, 2018, J/ApJ/866/99
Note (2): Derived from McQuillan+, 2014, J/ApJS/211/24, parts per million
Note (3): Derived from Kepler Input Catalog in Thompson+, 2016ksci.rept....3T,
Kepler Data Release 25 Notes (KSCI-19065-002)
Note (4): Some values are suspected in Sun-like stars (see Appendix A for
further details). Flags as follows:
1 = The rotation period can be different from McQuillan+, 2014, J/ApJS/211/24
2 = The binary candidate.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 17-May-2022