2018A&A...614A.122T


Query : 2018A&A...614A.122T

2018A&A...614A.122T - Astronomy and Astrophysics, volume 614A, 122-122 (2018/6-1)

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., SCHOFER 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. and SHULYAK D.

Abstract (from CDS):


Context. Previous simulations predicted the activity-induced radial-velocity (RV) variations of M dwarfs to range from ∼1 cm s–1 to ∼1 km s–1, depending on various stellar and activity parameters.
Aims. We investigate the observed relations between RVs, stellar activity, and stellar parameters of M dwarfs by analyzing CARMENES high-resolution visual-channel spectra (0.5-1µm), which were taken within the CARMENES RV planet survey during its first 20 months of operation.
Methods. 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 Hα emission. In addition, we estimated the chromatic index (CRX) of each spectrum, which is a measure of the RV wavelength dependence.
Results. Despite having a median number of only 11 measurements per star, we show that the RV variations of the stars with RV scatter of >10 m s–1 and a projected rotation velocity v sin i > 2 km s–1 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 (M0.0-2.5 V) through ∼30% for mid-type M dwarfs (M3.0-5.5 V) to >50% for late-type M dwarfs (M6.0-9.0 V). Their RV-scatter amplitude is found to be correlated mainly with v sin i. 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 Hα emission.
Conclusions. 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.

Abstract Copyright: © ESO 2018

Journal keyword(s): stars: late-type - stars: activity - stars: rotation - techniques: radial velocities

VizieR on-line data: <Available at CDS (J/A+A/614/A122): stars.dat table.dat>

Simbad objects: 35

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Number of rows : 35
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 Wolf 47 Er* 01 03 19.8350070578 +62 21 55.837228636   15.34 13.21 12.4   M5V 180 0
2 Barta 161 12 SB* 01 35 13.9246297464 -07 12 51.457318884   14.93 13.43 13.053 10.52 M4.3V 64 0
3 G 173-39 Er* 02 08 53.6246553758 +49 26 56.437533465   14.02 12.45 12.12   M4.0V 63 0
4 G 80-21 Er* 03 47 23.3412414313 -01 58 19.947831323 14.052 13.048 11.537 10.452 9.098 M3.0V 107 0
5 PM J04472+2038 Er* 04 47 12.2486067432 +20 38 10.797166356   16.0 14.216 13.988   M5.0V 30 0
6 V* V2689 Ori RS* 05 36 30.9904989312 +11 19 40.327533804 11.508 10.276 8.898 7.963 7.140 K6V 134 0
7 G 99-49 Er* 06 00 03.5042217306 +02 42 23.592579736   12.97 11.31 10.92 8.43 M3.5Ve 121 0
8 V* YZ CMi Er* 07 44 40.1723046464 +03 33 08.875227574 13.761 12.831 11.225 9.958 8.263 M4.0Ve 826 0
9 G 51-15 Er* 08 29 49.3527921926 +26 46 33.624143059   16.87   14.736   M6.5Ve 270 0
10 G 161-71 LM* 09 44 54.1925104432 -12 20 54.376191714   15.47 13.646 13.467 10.353 M5.0V 56 0
11 Wolf 359 Er* 10 56 28.9208702274 +07 00 53.003285286 16.706 15.541 13.507 11.684 9.507 dM6 671 0
12 StKM 2-809 PM* 12 15 39.3640825152 +52 39 08.752447512     12.564 12.197   M4.0V 31 0
13 V* GL Vir Er* 12 18 59.3997287457 +11 07 33.773236317   15.68 13.90 13.55   M4.5Ve 155 0
14 FBS 1415+456 PM* 14 17 22.1027369232 +45 25 46.006326264   15.73 14.21 13.93   dM5.0 23 0
15 NAME Proxima Centauri Er* 14 29 42.9461331854 -62 40 46.164680672 14.21 12.95 11.13 9.45 7.41 M5.5Ve 1128 0
16 V* OT Ser PM* 15 21 52.9325510712 +20 58 39.910874376 12.662 11.522 10.003 8.993 7.843 M1.0V 123 0
17 G 256-25 PM* 15 49 55.1359495320 +79 39 51.588172332   16.3   14.408   M5.0V 28 0
18 G 180-60 Er* 16 31 18.7890584283 +40 51 51.705530284   16.5   14.550   M6V 54 0
19 VB 8 Er* 16 55 35.2557374336 -08 23 40.753073075   18.7 16.916 14.566 12.24 M7Ve 412 0
20 G 19-7 Er* 16 57 05.7362228328 -04 20 56.318033870   13.92 12.25 10.99 9.432 dM4 88 0
21 CD-46 11540 LM* 17 28 39.9455781571 -46 53 42.688095874 12.177 10.973 9.407 8.337 7.006 M3V 229 1
22 V* V1274 Her BY* 17 33 53.1782383296 +16 55 13.066432788   16.13 14.38 14.04 10.896 M6V 38 0
23 NAME Barnard's star BY* 17 57 48.4984700685 +04 41 36.113879676 12.497 11.24 9.511 8.298 6.741 M4V 739 2
24 G 227-22 PM* 18 02 16.6038674062 +64 15 44.241600544   14.74   13.010   M5.0V 64 0
25 G 258-33 Er* 18 18 57.2325828283 +66 11 33.304331650   15.29   13.096   M4.5V 80 0
26 LSR J1835+3259 PM* 18 35 37.8801226673 +32 59 53.316099140   20.0   17.1   M8.5V 113 0
27 Ross 154 Er* 18 49 49.3637762005 -23 50 10.447375350 13.528 12.19 10.43 10.23 7.703 M3.5Ve 351 0
28 VB 10 Er* 19 16 57.6109547886 +05 09 01.600923413     17.30     M8V 459 1
29 LSPM J1925+0938 PM* 19 25 30.9143137536 +09 38 23.325281124   19.2   16.7   M8/9V 20 0
30 G 208-42 Er* 19 51 09.3205973189 +46 29 00.213809780   14.47   12.544   M4.0V 150 0
31 SCR J2009-0113 PM* 20 09 18.2477138814 -01 13 38.312815011   16.265 14.450 14.128 11.16 M5.0V 26 0
32 V* V374 Peg Er* 22 01 13.1241989539 +28 18 24.907312662       11.602   M3.5Ve 196 0
33 V* EV Lac Er* 22 46 49.7312610268 +44 20 02.374381562   11.85 10.26 9.89   M4.0V 846 2
34 V* GT Peg BY* 22 51 53.5351209551 +31 45 15.192825225       11.281   M3.5V 149 0
35 RX J2354.8+3831 PM* 23 54 51.4580576376 +38 31 36.200975556   14.78   12.94   M3.1V 38 0

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2022.05.24-05:46:54

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