J/AJ/159/60 8695 flares from 1228 stars in TESS sectors 1 & 2 (Gunther+, 2020)
Stellar flares from the first TESS data release: exploring a new sample of
M-Dwarfs.
Gunther M.N., Zhan Z., Seager S., Rimmer P.B., Ranjan S., Stassun K.G.,
Oelkers R.J., Daylan T., Newton E., Kristiansen M.H., Olah K., Gillen E.,
Rappaport S., Ricker G.R., Vanderspek R.K., Latham D.W., Winn J.N.,
Jenkins J.M., Glidden A., Fausnaugh M., Levine A.M., Dittmann J.A.,
Quinn S.N., Krishnamurthy A., Ting E.B.
<Astron. J., 159, 60 (2020)>
=2020AJ....159...60G 2020AJ....159...60G
ADC_Keywords: Stars, flare; Stars, M-type; Optical; Surveys;
Effective temperatures; Stars, diameters; Spectral types
Keywords: Optical flares ; Exoplanets ; Habitable planets ;
Red dwarf flare stars ; Stellar flares ; Stellar activity ;
Habitable zone ; Extrasolar rocky planets ; Astrobiology ;
Pre-biotic astrochemistry ; Exoplanet atmospheres
Abstract:
We perform a study of stellar flares for the 24809 stars observed with
2 minute cadence during the first two months of the Transiting
Exoplanet Survey Satellite (TESS) mission. Flares may erode
exoplanets' atmospheres and impact their habitability, but might also
trigger the genesis of life around small stars. TESS provides a new
sample of bright dwarf stars in our galactic neighborhood, collecting
data for thousands of M dwarfs that might host habitable exoplanets.
Here, we use an automated search for flares accompanied by visual
inspection. Then, our public allesfitter code robustly selects the
appropriate model for potentially complex flares via Bayesian
evidence. We identify 1228 flaring stars, 673 of which are M dwarfs.
Among 8695 flares in total, the largest superflare increased the
stellar brightness by a factor of 16.1. Bolometric flare energies
range from 1031.0 to 1036.9erg, with a median of 1033.1erg.
Furthermore, we study the flare rate and energy as a function of
stellar type and rotation period. We solidify past findings that fast
rotating M dwarfs are the most likely to flare and that their flare
amplitude is independent of the rotation period. Finally, we link our
results to criteria for prebiotic chemistry, atmospheric loss through
coronal mass ejections, and ozone sterilization. Four of our flaring M
dwarfs host exoplanet candidates alerted on by TESS, for which we
discuss how these effects can impact life. With upcoming TESS data
releases, our flare analysis can be expanded to almost all bright
small stars, aiding in defining criteria for exoplanet habitability.
Description:
The Transiting Exoplanet Survey Satellite (TESS) mission, launched in
2018 April, provides the opportunity to study flares on early to late
M dwarfs. Here, we present findings derived from the first two months
of TESS data (i.e., sectors 1 and 2).
The TESS detector bandpass spans from 600-1000nm and is centered on
the traditional Cousins I-band (central wavelength=786.5nm). Four 10cm
optical cameras simultaneously observe a total field of 24degx96deg.
We find 1228 flaring stars in the first two TESS sectors, with a total
count of 8695 flares.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 258 8695 Catalog of all individual flares found in the
Transiting Exoplanet Survey Satellite (TESS)
sectors 1 and 2
table2.dat 191 1228 Catalog of all flaring stars found in TESS
sectors 1 and 2
--------------------------------------------------------------------------------
See also:
IV/38 : TESS Input Catalog - v8.0 (TIC-8) (Stassun+, 2019)
J/AJ/128/463 : A 20pc census from the NLTT catalogue (Reid+, 2004)
J/AJ/135/785 : SDSS-DR5 low-mass star spectroscopic sample (West+, 2008)
J/AJ/141/50 : White-light flares cool stars from Kepler (Walkowicz+, 2011)
J/other/Nat/485.478 : Superflares on solar-type stars (Maehara+, 2012)
J/ApJS/207/15 : M dwarf flare spectra (Kowalski+, 2013)
J/ApJS/208/9 : Intrinsic colors & temperatures of PMS stars (Pecaut+, 2013)
J/ApJS/209/5 : Superflares of Kepler stars. I. (Shibayama+, 2013)
J/MNRAS/445/2268 : Bayesian method for detecting stellar flares (Pitkin+, 2014)
J/ApJ/812/3 : MEarth mid-to-late M dwarfs rotat. & kinematics (West+,2015)
J/ApJ/814/91 : Comparative habitability of exoplanets (Barnes+, 2015)
J/ApJ/814/35 : Flare events in M dwarf of M37 (Chang+, 2015)
J/ApJ/829/23 : Stellar flares from Q0-Q17 Kepler LCs (Davenport, 2016)
J/ApJ/821/93 : Rotation & Galactic kinematics mid M dwarfs (Newton+, 2016)
J/MNRAS/463/1844 : M dwarfs rotation-activity relation (Stelzer+, 2016)
J/A+A/600/A13 : HARPS M dwarf magnetic activity (Astudillo-Defru+, 2017)
J/AJ/153/93 : MOST photometry of Proxima (Kipping+, 2017)
J/ApJ/834/85 : Hα emission in nearby M dwarfs (Newton+, 2017)
J/ApJS/232/26 : Catalog of Kepler flare stars (Van Doorsselaere+, 2017)
J/ApJ/843/31 : MUSCLES Treasury Survey. IV. (Youngblood+, 2017)
J/MNRAS/465/1789 : SCUBA-2 Cosmology Legacy Survey (Geach+, 2017)
J/AJ/156/217 : Properties for M dwarfs in MEarth-South (Newton+, 2018)
J/AJ/155/39 : Variability properties of TIC sources KELT (Oelkers+, 2018)
J/ApJS/241/12 : The Asteroseismic Target List (ATL) TESS (Schofield+, 2019)
http://archive.stsci.edu/prepds/tess-data-alerts/ : TESS data alerts home page
http://heasarc.gsfc.nasa.gov/docs/tess : NASA's TESS home page
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 I9 --- TIC [2760232/471015484] TESS input catalog
identifier
11- 11 I1 --- Sec [1/2] TESS sector
13- 14 I2 --- Outbst [1/58] Outburst number
16- 16 I1 --- Flare [1/5] Flare number
18- 31 F14.6 d tpeak [2458325/2458382] Peak time, posterior median,
flare, Barycentric Julian Date
33- 40 F8.6 d e_tpeak [2e-6/0.046] Lower uncertainty on tpeak
42- 49 F8.6 d E_tpeak [2e-6/0.065] Upper uncertainty on tpeak
51- 58 F8.5 --- Amp [0.00065/16] Flare amplitude, relative
60- 66 F7.5 --- e_Amp [7e-5/3.4] Lower uncertainty on Amp
68- 74 F7.5 --- E_Amp [7e-5/1.5] Upper uncertainty on Amp
76- 82 F7.5 d FWHMdt [0.0001/0.08] Full-width at half-maximum,
flare duration
84- 90 F7.5 d e_FWHMdt [2e-05/0.05] Lower uncertainty on FWHMdt
92- 98 F7.5 d E_FWHMdt [2e-05/0.08] Upper uncertainty on FWHMdt
100-108 E9.3 10-7J Ebol [1e+30/9e+36]? Bolometric energy, flare;
in erg units
110-118 E9.3 10-7J e_Ebol [1e+30/2e+36]? Lower uncertainty on Ebol
120-128 E9.3 10-7J E_Ebol [1e+30/4e+36]? Upper uncertainty on Ebol
130-138 E9.3 g MCME [1e+18/3e+22]? Possible mass of a coronal mass
ejection post flare
140-148 E9.3 g e_MCME [1e+18/3e+22]? Lower uncertainty on MCME
150-158 E9.3 g E_MCME [1e+19/2e+24]? Upper uncertainty on MCME
160-167 F8.5 mag Tmag [3/17] TESS magnitude, star
169-173 I5 K Teff [2801/31000]? Stellar effective temperature
175-183 F9.6 Rsun Rad [0.1/46]? Stellar radius
185-191 F7.5 [cm/s2] logg [3.6/5.6]? Log, surface gravity
193-198 A6 --- SpT Spectral Type
200-207 F8.6 d Prot-t [0.003/5]? Rotation period extracted, TESS
209-217 F9.6 d Prot-k [0.5/46]? Rotation period extracted, KELT
219-227 F9.6 d Prot [0.003/39]? Accepted rotational period
229-234 F6.3 --- aFFD [-3.6/-0.27]? Fit slope (αFFD),
log10(flare rate) vs log10(Ebol)
236-242 F7.3 --- bFFD [8.3/117]? Fit intercept (βFFD),
log10(flare rate) vs log10(Ebol)
244-244 I1 --- Chem [0/1] Trigger prebiotic chemistry code
(1=yes; 122 occurrences)
246-246 I1 --- O3cons [0/1] Ozone depletion, conservative
threshold code (1=yes; 340 occurrences)
248-248 I1 --- O3perm [0/1] Ozone depletion, permissive threshold
code (1=yes; 1291 occurrences)
250-258 I9 --- Dup [0/471015484] TESS ID of duplicate
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 I9 --- TIC [2760232/471015484] TESS input catalog
identifier
11- 11 I1 --- Sec [1/2] TESS sector
13- 14 I2 --- Nout [1/77] Number of outbursts
16- 18 I3 --- Nfl [1/109] Number of flares
20- 27 F8.5 --- Amp_max [0.001/16] Flare amplitude, relative,
maximum
29- 35 F7.5 --- Amp_mean [0.0009/6.6] Flare amplitude, relative, mean
37- 43 F7.5 d FWHMdt_max [0.00022/0.08] Full-width at half-maximum,
maximum duration
45- 51 F7.5 d FWHMdt_mean [0.00022/0.06] Full-width at half-maximum,
mean duration
53- 61 E9.3 10-7J Ebol_max [1e+31/9e+36]? Bolometric energy, max;
in erg units
63- 71 E9.3 10-7J Ebol_mean [1e+31/5e+36]? Bolometric energy, mean;
in erg units
73- 81 E9.3 g MCME_max [1e+19/3e+22]? Possible mass of a coronal
mass ejection post flare, max
83- 91 E9.3 g MCME_mean [1e+19/2e+22]? Possible mass of a coronal
mass ejection post flare, mean
93-100 F8.5 mag Tmag [3.7/17] TESS magnitude, star
102-106 I5 K Teff [2801/31000]? Stellar effective temperature
108-116 F9.6 Rsun Rad [0.11/46]? Stellar radius
118-124 F7.5 [cm/s2] logg [3.6/5.6]? Log, surface gravity
126-131 A6 --- SpT Spectral Type
133-140 F8.6 d Prot-t [0.003/5]? Rotation period extracted, TESS
142-150 F9.6 d Prot-k [0.51/46]? Rotation period extracted, KELT
152-160 F9.6 d Prot [0.0033/39]? Accepted rotational period
162-167 F6.3 --- aFFD [-3.6/-0.27]? Fit slope (αFFD),
log10(flare rate) vs log10(Ebol)
169-175 F7.3 --- bFFD [8.3/117]? Fit intercept (βFFD),
log10(flare rate) vs log10(Ebol)
177-177 I1 --- Chem [0/1] Trigger prebiotic chemistry code
(1=yes; 14 occurrences)
179-179 I1 --- O3cons [0/1] Ozone depletion, conservative
threshold code (1=yes; 22 occurrences)
181-181 I1 --- O3perm [0/1] Ozone depletion, permissive threshold
code (1=yes; 100 occurrences)
183-191 I9 --- Dup [0/471015484] TESS ID of duplicate
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 06-Mar-2020