J/A+A/600/A13 HARPS M dwarf sample magnetic activity (Astudillo-Defru+, 2017)
Magnetic activity in the HARPS M dwarf sample.
The rotation-activity relationship for very low-mass stars through R'HK.
Astudillo-Defru N., Delfosse X., Bonfils X., Forveille T., Lovis C.,
Rameau J.
<Astron. Astrophys. 600, A13 (2017)>
=2017A&A...600A..13A 2017A&A...600A..13A (SIMBAD/NED BibCode)
ADC_Keywords: Stars, M-type ; Stars, dwarfs ; Stars, masses ; Spectroscopy
Keywords: stars: activity - stars: late-type - stars: rotation -
stars: planetary systems - techniques: spectroscopic
Abstract:
Atmospheric magnetic fields in stars with convective envelopes heat
stellar chromospheres, and thus increase the observed flux in the CaII
H and K doublet. Starting with the historical Mount Wilson monitoring
program, these two spectral lines have been widely used to trace
stellar magnetic activity, and as a proxy for rotation period (Prot)
and consequently for stellar age. Monitoring stellar activity has also
become essential in filtering out false-positives due to magnetic
activity in extra-solar planet surveys. The CaII emission is
traditionally quantified through the R'HK-index, which compares the
chromospheric flux in the doublet to the overall bolometric flux of
the star. Much work has been done to characterize this index for
FGK-dwarfs, but M dwarfs - the most numerous stars of the Galaxy -
were left out of these analyses and no calibration of their CaII H and
K emission to an R'HK exists to date.
We set out to characterize the magnetic activity of the low- and
very-low-mass stars by providing a calibration of the R'HK-index
that extends to the realm of M dwarfs, and by evaluating the
relationship between R'HK and the rotation period..
We calibrated the bolometric and photospheric factors for M dwarfs to
properly transform the S-index (which compares the flux in the CaII H
and K lines to a close spectral continuum) into the R'HK. We
monitored magnetic activity through the CaII H and K emission lines in
the HARPS M dwarf sample.
Description:
R'HK analysis for the HARPS M dwarf sample. Updated relationships for
the bolometric factor and photospheric correction are used to
transform the CaH&K emission to the R'HK. A relationship is obtained
for the R'HK vs. Prot dependence, and used to estimate the stellar
rotation for the HARPS M dwarf sample.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea3.dat 87 403 Parameters, activity and rotation periods for
the HARPS M dwarf sample
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See also:
I/311 : Hipparcos, the New Reduction (van Leeuwen, 2007)
J/AJ/142/138 : All-sky catalog of bright M dwarfs (Lepine+, 2011)
J/ApJ/752/56 : BDKP III. Parallaxes for 70 ultracool dwarfs (Faherty+ 2012)
J/MNRAS/443/2561 : CONCH-SHELL catalog of nearby M dwarfs (Gaidos+, 2014)
Byte-by-byte Description of file: tablea3.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Name Object name
11- 15 F5.2 mag Vmag Visual magnitude
17- 20 F4.2 mag B-V B-V color index
22- 26 F5.3 mag V-K V-K color index
28- 33 F6.2 mas plx Parallax
35- 39 F5.2 mas e_plx Parallax uncertainty
41 I1 --- r_Vmag [1/2] Reference for the photometry (1)
43 I1 --- r_plx [2/7] Reference for the parallax (1)
45- 48 F4.2 Msun Mass Stellar mass
50- 52 I3 --- Nsp Number of spectra used in the analysis
54- 59 F6.3 --- S S-index
61- 65 F5.3 --- e_S S-index uncertainty
67- 72 F6.3 --- log(R'HK) logarithm R'HK-index
74- 78 F5.3 --- e_log(R'HK) R'HK-index uncertainty
80- 82 I3 d Prot Stellar rotation
84- 87 F4.1 --- SNR Average SNR in the violet and red bands
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Note (1): References as follows:
1 = Leggett (1992ApJS...82..351L 1992ApJS...82..351L)
2 = Gaidos et al. (2014, Cat. J/MNRAS/443/2561)
3 = van Leeuwen (2007A&A...474..653V 2007A&A...474..653V, Cat. I/311)
4 = van Altena et al. (1995, Cat. I/238)
5 = RECONS, research consortium on nearby stars parallax program (e.g.,
Riedel et al. 2010AJ....140..897R 2010AJ....140..897R; Jao et al. 2011AJ....141..117J 2011AJ....141..117J).
6 = Lepine & Gaidos (2011, Cat. J/AJ/142/138)
7 = Hawley et al. (1997AJ....113.1458H 1997AJ....113.1458H)
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Acknowledgements:
Nicola Astudillo-Defru, nicola.astudillo(at)unige.ch
(End) Patricia Vannier [CDS] 01-Feb-2017