J/A+A/614/A122 Radial-velocity of CARMENES M dwarfs (Tal-Or+, 2018)
The CARMENES search for exoplanets around M dwarfs.
Radial-velocity variations of active stars in visual-channel spectra.
Tal-Or L., Zechmeister M., Reiners A., Jeffers S.V., Schoefer P.,
Quirrenbach A., Amado P.J., Ribas I., Caballero J.A., Aceituno J.,
Bauer F.F., Bejar V.J.S., Czesla S., Dreizler S., Fuhrmeister B.,
Hatzes A.P., Johnson E.N., Kurster M., Lafarga M., Montes D.,
Morales J.C., Reffert S., Sadegi S., Seifert W., Shulyak D.
<Astron. Astrophys. 614, A122 (2018)>
=2018A&A...614A.122T 2018A&A...614A.122T (SIMBAD/NED BibCode)
ADC_Keywords: Stars, late-type; Stars, M-type; Radial velocities; Balmer lines
Keywords: stars: late-type - stars: activity - stars: rotation -
techniques: radial velocities
Abstract:
Previous simulations predicted the activity-induced radial-velocity
(RV) variations of M dwarfs to range from ∼1cm/s to ∼1km/s, depending
on various stellar and activity parameters. We investigate the
observed relations between RVs, stellar activity, and stellar
parameters of M dwarfs by analyzing CARMENES high-resolution
visual-channel spectra (0.5-1um), which were taken within the CARMENES
RV planet survey during its first 20 months of operation. During this
time, 287 of the CARMENES- sample stars were observed at least five
times. From each spectrum we derived a relative RV and a measure of
chromospheric Halpha emission. In addition, we estimated the chromatic
index (CRX) of each spectrum, which is a measure of the RV wavelength
dependence. Despite having a median number of only 11 measurements per
star, we show that the RV variations of the stars with RV scatter of
>10m/s and a projected rotation velocity vsini>2km/s are caused mainly
by activity. We name these stars 'active RV-loud stars' and find their
occurrence to increase with spectral type: from ∼3% for early-type M
dwarfs (M0.0-2.5V) through ∼30% for mid-type M dwarfs (M3.0-5.5V) to
>50% for late-type M dwarfs (M6.0-9.0V). Their RV-scatter amplitude is
found to be correlated mainly with vsini. For about half of the stars,
we also find a linear RV-CRX anticorrelation, which indicates that
their activity-induced RV scatter is lower at longer wavelengths. For
most of them we can exclude a linear correlation between RV and Halpha
emission. Our results are in agreement with simulated activity-induced
RV variations in M dwarfs. The RV variations of most active RV-loud M
dwarfs are likely to be caused by dark spots on their surfaces, which
move in and out of view as the stars rotate.
Description:
The catalogue contains the data presented in Figures 5 and A.1 of the
source paper.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
stars.dat 63 31 List of studied stars
table.dat 72 649 The data presented in Figures 5 and A1
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See also:
J/A+A/577/A128 : CARMENES input catalog of M dwarfs I (Alonso-Floriano+, 2015)
J/A+A/597/A47 : CARMENES input catalog of M dwarfs II (Cortes-Contreras+ 2017)
J/A+A/609/A117 : CARMENES radial velocity curves of 7 M-dwarf (Trifonov+, 2018)
J/A+A/609/L5 : CARMENES radial velocity curves of HD147379 b (Reiners+, 2018)
J/A+A/612/A49 : 324 CARMENES M dwarfs velocities (Reiners+, 2018)
Byte-by-byte Description of file: stars.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Karmn Karmn designation
13- 14 I2 h RAh Right ascension (J2000)
16- 17 I2 min RAm Right ascension (J2000)
19- 23 F5.2 s RAs Right ascension (J2000)
25 A1 --- DE- Declination sign (J2000)
26- 27 I2 deg DEd Declination (J2000)
29- 30 I2 arcmin DEm Declination (J2000)
32- 35 F4.1 arcsec DEs Declination (J2000)
37- 39 I3 --- N Number of measurments in table.dat
41- 63 A23 --- SName Simbad name
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Byte-by-byte Description of file: table.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Karmn Karmn designation
12- 18 F7.1 m/s RV Radial velocity
20- 25 F6.1 m/s e_RV Radial velocity error
27- 34 F8.1 --- CRX Chromatic index (in m/s/Neper)
36- 42 F7.1 --- e_CRX Chromatic index error (in m/s/Neper)
44- 50 F7.1 1000m+2/s+2 dLW Differential line width
52- 58 F7.1 1000m+2/s+2 e_dLW dLW error
60- 65 F6.3 --- log(LHa/Lbol) ? Halpha luminosity
67- 72 F6.3 --- e_log(LHa/Lbol) ? Halpha luminosity error
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Acknowledgements:
Lev Tal-Or, levtalor(at)astro.physik.uni-goettingen.de
Inst. fur Astrophysik Univ. Goettingen
(End) L. Tal-Or [Inst. fur Astrophysik Goettingen], P. Vannier [CDS] 08-Mar-2018