J/A+A/665/A30 Flares and rotation of M dwarfs (Stelzer+, 2022)
Flares and rotation of M dwarfs with habitable zones accessible to TESS planet
detections.
Stelzer B., Bogner M., Magaudda E., Raetz St.
<Astron. Astrophys. 665, A30 (2022)>
=2022A&A...665A..30S 2022A&A...665A..30S (SIMBAD/NED BibCode)
ADC_Keywords: Stars, M-type ; X-ray sources
Keywords: stars: flare - stars: late-type - stars: activity - stars: rotation
Abstract:
More than 4000 exoplanets have been discovered to date, providing the
search for a place capable of hosting life with a large number of
targets. With the Transiting Exoplanet Survey Satellite (TESS) having
completed its primary mission in July 2020, the number of planets
confirmed by follow-up observations is growing further. Crucial for
planetary habitability is not only a suitable distance of the planet
to its host star, but also the star's properties. Stellar magnetic
activity, and especially flare events, expose planets to a high photon
flux and potentially erode their atmospheres. Here especially the
poorly constrained high-energy UV and X-ray domain is relevant.
We characterize the magnetic activity of M dwarfs to provide the
planet community with information on the energy input from the star;
in particular, next to the frequency of optical flares directly
observed with TESS we aim at estimating the corresponding X-ray flare
frequencies making use of the small pool of known events observed
simultaneously in both wavebands.
We identified 112 M dwarfs with a TESS magnitude ≤11.5 for which
TESS can probe the full habitable zone for transits. These 112 stars
have 1276 two-minute cadence TESS light curves from the primary
mission which we searched for rotational modulation and flares. We
study the link between rotation and flares and between flare
properties, e.g. the flare amplitude-duration relation and cumulative
flare energy frequency distributions (FFDs). Assuming that each
optical flare is associated to a flare in the X-ray band, and making
use of published simultaneous Kepler/K2 and XMM-Newton flare studies,
we estimate the X-ray energy released by our detected TESS flare
events. Our calibration involves also the relation between flare
energies in the TESS and K2 band.
We detected more than 2500 optical flare events on a fraction of about
32% of our targets and found reliable rotation periods only for 12
stars which is a fraction of about 11%. For these 12 targets, we
present cumulative flare energy frequency distributions (FFDs) and FFD
power law fits. We construct FFDs in the X-ray band by calibrating
optical flare energies to the X-rays. In the absence of directly
observed X-ray FFDs for main-sequence stars, our predictions can serve
for estimates of the high-energy input to the planet of a typical
fast-rotating early- or mid-M dwarf.
Description:
The M dwarfs catalog based on the analysis of TESS light curves and
containing 112 stars for which stellar parameters, astrometric, and
photometric data are calculated and collected in these tables. This
catalog contains also the results from the analysis of TESS light
curves, providing information on rotation, flare detections, and
contamination for all stars studied in this work.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 59 2532 Flare parameters (for 35 stars)
tablea1.dat 130 112 Stellar parameters for our 112 sample stars
tablea2.dat 124 30 Stellar parameters for CPM pairs
tablea3.dat 78 112 Results of the rotation and flare search and
contamination analysis for all stars
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See also:
IV/38 : TESS Input Catalog - v8.0 (TIC-8) (Stassun+, 2019)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 9 I9 --- TIC TIC number
11- 21 F11.6 d Flare-start Time of flare start (JD-2450000)
23- 33 F11.6 d Flare-max Time of flare maximum (JD-2450000)
35- 39 F5.3 --- Apeak Normalized flare amplitude
41- 45 F5.2 --- logDeltaLFT Absolute flare amplitude
47- 53 F7.2 --- ED Equivalent duration
55- 59 F5.2 --- logEflare Flare energy
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 9 I9 --- TIC TIC number from TESS observation
11- 33 A23 --- OName Literature name from Simbad
35- 53 I19 --- GaiaDR2 Gaia-DR2 ID (G1)
55- 70 A16 --- 2MASS 2MASS IDs
(Skrutskie et al., 2006, Cat. VII/233)
72- 78 F7.3 deg RAdeg Right Ascension from TIC observations (J2000)
80- 86 F7.3 deg DEdeg Declination from TIC observations (J2000)
88- 92 F5.2 mag Tmag TESS magnitude
94- 98 F5.3 Msun Mstar Stellar mass (G2)
100-104 F5.3 Msun e_Mstar rms uncertainty on stellar mass (G2)
106-111 F6.3 pc Dist Gaia-DR2 distance (G3)
113-117 F5.3 pc e_Dist rms uncertainty of Gaia-DR2 distance (G3)
119-122 F4.1 --- SpType Spectral type (G4)
124-128 F5.2 [10-7W] logLquiT Quiescent luminosity in TESS band
130 I1 --- CPMflag [0/1] Common proper motion flag (G5)
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Byte-by-byte Description of file: tablea2.dat
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Bytes Format Units Label Explanations
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1- 9 I9 --- TIC ?=- TIC number
11- 29 I19 --- GaiaDR2 Gaia-DR2 ID (G1)
31- 46 A16 --- 2MASS 2MASS IDs
(Skrutskie et al., 2006, Cat. VII/233)
48- 53 F6.3 pc Dist Gaia-DR2 distance (G3)
55- 59 F5.3 pc e_Dist Uncertainty on Gaia-DR2 distance (G3)
61- 65 F5.2 mag RPmag Gaia magnitude in RP band (G1)
67- 71 F5.3 Rsun Rstar ?=- Stellar radius (G2)
73- 77 F5.3 Rsun e_Rstar ?=- Uncertainty on the stellar radius (G2)
79- 82 I4 K Teff ?=- Effective temperature (G2)
84- 86 I3 K e_Teff ?=- Uncertainty on the effective
temperature (G2)
88- 92 F5.3 Msun Mstar ?=- Stellar mass (G2)
94- 98 F5.3 Msun e_Mstar ?=- Uncertainty on the stellar mass (G2)
100-104 A5 --- SpType Spectral type (G4)
106-110 F5.2 arcsec Sep ?=- Angular separation from the p.m.
companion star
112-117 I6 --- FlagSep [0/1]?=-32768 Flag on the separation (1)
119-124 I6 --- FlagComp [0/1]?=-32768 Flag on the proper motion
companion (2)
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Note (1): Flag on the separation as follows:
1 = the separation is taken from WDS
0 = the separation is calculated using Gaia-DR2 coordinates
Note (2): 1 if the companions are unresolved by Gaia-DR2/2MASS
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Byte-by-byte Description of file: tablea3.dat
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Bytes Format Units Label Explanations
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1- 9 I9 --- TIC TIC number
11- 33 A23 --- ObsSectors TESS sectors where the star is observed
35- 40 F6.2 --- Obs.dur Duration of the observation
42- 47 F6.1 --- contfactmean ?=9999 Averaged contamination factor (1)
49- 54 F6.1 --- contfactmin ?=9999 The minimum contamination factor (1)
56- 61 F6.1 --- contfactmax ?=9999 The maximum contamination factor (1)
63- 66 F4.2 --- Prot ?=- Rotation period
68- 70 I3 --- Nflarestot Total number of flares
72- 76 F5.3 d-1 Nflaresdaythres Flare frequency (Nflaresdaythres)
78 I1 --- CPMflag [0/1] Common proper motion flag(2)
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Note (1): 9999 indicates stars that have been excluded from the analysis because
the target is outside the mask.
Note (2): 1 if the star is part of a common proper motion system
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Global notes:
Note (G1): Gaia source from Gaia Collaboration et al. (2016, Cat. I/337,
2018, Cat. I/345).
Note (G2): Calculated with Mann et al. (2015ApJ...804...64M 2015ApJ...804...64M, 2016) relations.
Note (G3): Distance from Bailer et al. (2018, Cat. I/347).
Note (G4): Spectral types are calculated from Gbp-Gbp and G-Grp colors using the
table A Modern Mean Dwarf Stellar Color and Effective Temperature Sequence,
maintained by E. Mamajek
Note (G5): 1 if the star is part of a common proper motion system
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Acknowledgements:
Enza Magaudda, magaudda(at)astro.uni-tuebingen.de
(End) Patricia Vannier [CDS] 11-Jun-2022