J/A+A/675/A168 Stellar properties of 177 M dwarfs (Mignon+, 2023)
Characterisation of stellar activity of M dwarfs.
I. Long timescale variability on a large sample and detection of new cycles.
Mignon L., Meunier N., Delfosse X., Bonfils X., Santos N.C., Forveille T.,
Gaisne G., Astudillo-Defru N., Lovis C., Udry S.
<Astron. Astrophys. 675, A168 (2023)>
=2023A&A...675A.168M 2023A&A...675A.168M (SIMBAD/NED BibCode)
ADC_Keywords: Stars, M-type ; Spectroscopy ; Photometry ; Optical
Keywords: stars: activity - stars: chromospheres - techniques: spectroscopy -
planetary systems
Abstract:
M dwarfs are active stars that exhibit variability in chromospheric
emission and photometry at short and long timescales, including long
cycles that are related to dynamo processes. This activity also
impacts the search for exoplanets because it affects the radial
velocities.
We analysed a large sample of 177 M dwarfs observed with HARPS during
the period 2003-2020 in order to characterise the long-term
variability of these stars. We compared the variability obtained in
three chromospheric activity indices (Ca-II H & K, the Na D doublet,
and Hα) and with ASAS photometry.
We focused on the detailed analysis of the chromospheric emission
based on linear, quadratic, and sinusoidal models. We used various
tools to estimate the significance of the variability and to quantify
the improvement brought by the models. In addition, we analysed
complementary photometric time series for the most variable stars to
be able to provide a broader view of the long-term variability in M
dwarfs.
We find that most stars are significantly variable, even the quietest
stars. Most stars in our sample (75%) exhibit a long-term variability,
which manifests itself mostly through linear or quadratic variability,
although the true behaviour may be more complex. We found significant
variability with estimated timescales for 24 stars, and estimated the
lower limit for a possible cycle period for an additional 9 stars that
were not previously published. We found evidence of complex
variability because more than one long-term timescale may be present
for at least 12 stars, together with significant differences between
the behaviour of the three activity indices. This complexity may also
be the source of the discrepancies observed between previous
publications.
We conclude that long-term variability is present for all spectral
types and activity level in M dwarfs, without a significant trend with
spectral type or mean activity level.
Description:
Stellar properties of our sample of 177 stars in our sample.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tableb1.dat 67 177 Stellar properties of our sample of 177 stars
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See also:
I/311 : Hipparcos, the New Reduction (van Leeuwen, 2007)
I/344 : The URAT Parallax Catalog (UPC). Update 2018 (Finch+, 2018)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
II/237 : Stellar photometry in Johnson's 11-color system
(Ducati, 2002)
J/MNRAS/403/1949 : UBV(RcIc)JHK photometry of HIP nearby stars (Koen+, 2010)
J/AJ/152/24 : Trigonometric parallaxes of 134 low-mass stars
(Weinberger+, 2016)
Byte-by-byte Description of file: tableb1.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Star name
16- 20 F5.3 mag V-K V-K colour index (1)
22 A1 --- n_V-K [d] d indicates calculated V-K (1)
24- 27 I4 K Teff ? Effective temperature, from CDS
30- 34 F5.3 Msun Mass Mass (2)
37- 41 F5.2 pc Dist Distance (3)
43- 46 I4 --- Nnights Number of nights
49- 54 F6.3 [-] logR'HK Averaged LogR'HK
59- 63 F5.3 --- rmsR'HK rms R'HK x 105
67 A1 --- Season [X] X indicates star in the season subsample
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Note (1): V-K is in most cases from the CDS, and "d" in the third columns
indicates V-K derived from the relationship between G-K versus V-K when V
is not available.
Note (2): Masses are from the mass-luminosity relationship of Delfosse et al.
(2000A&A...364..217D 2000A&A...364..217D), with a weighted average of the masses derived from
H, K and J from the CDS: these band magnitudes were taken from the
2MASS database Cutri et al. (2003yCat.2246....0C 2003yCat.2246....0C, Cat. II/246) with the
exception of:
GJ205 : H and J from Ducati et al. (2002yCat.2237....0D 2002yCat.2237....0D, Cat. II/237)
GJ1 and GJ803 : K from Koen et al. (2010MNRAS.403.1949K 2010MNRAS.403.1949K,
Cat. J/MNRAS/403/1949)
Note (3): Most distances are from Gaia Collaboration (2018yCat.1345....0G 2018yCat.1345....0G,
Cat. I/345). When not available, distances are derived from the following
parallaxes:
GJ257, GJ2033, GJ4206, GJ9163 and HD196982 from van Leeuwen et al.
(2007A&A...474..653V 2007A&A...474..653V, Cat. I/311)
GJ406 from Weinberger et al. (2016AJ....152...24W 2016AJ....152...24W, Cat. J/AJ/152/24)
GJ3813 and GJ4038 from Finch et al. (2018arXiv180208272F 2018arXiv180208272F, Cat. I/344)
GJ3256 from Gaia DR3 https://gea.esac.esa.int/archive/
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Acknowledgements:
Lucile Mignon, Lucile.Mignon(at)unige.ch
(End) Patricia Vannier [CDS] 01-Mar-2023