J/A+A/663/A48 Two Saturn-mass planets around M dwarfs (Quirrenbach+, 2022)
The CARMENES search for exoplanets around M dwarfs.
Two Saturn-mass planets orbiting active stars.
Quirrenbach A., Passegger V.M., Trifonov T., Amado P.J., Caballero J.A.,
Reiners A., Ribas I., Aceituno J., Bejar V.J.S., Chaturvedi P.,
Gonzalez-Cuesta L., Henning T., Herrero E., Kaminski A., Kuerster M.,
Lalitha S., Lodieu N., Lopez-Gonzalez M.J., Montes D., Palle E., Perger M.,
Pollacco D., Reffert S., Rodriguez E., Rodriguez Lopez C., Shan Y.,
Tal-Or L., Zapatero Osorio M.R., Zechmeister M.
<Astron. Astrophys. 663, A48 (2022)>
=2022A&A...663A..48Q 2022A&A...663A..48Q (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Exoplanets ; Radial velocities ;
Optical
Keywords: planets and satellites: detection -
planets and satellites: formation - stars: individual: TZ Ari -
stars: individual: TYC 2187-512-1 - stars: low-mass -
techniques: radial velocities
Abstract:
The CARMENES radial-velocity survey is currently searching for planets
in a sample of 387 M dwarfs. Here we report on two Saturn-mass planets
orbiting TYC 2187-512-1 (Mstar=0.50M☉) and TZ Ari
(Mstar=0.15M☉), respectively. We obtained supplementary
photometric time series, which we use along with spectroscopic
information to determine the rotation periods of the two stars. In
both cases, the radial velocities also show strong modulations at the
respective rotation period. We thus modeled the radial velocities as a
Keplerian orbit plus a Gaussian process representing the stellar
variability. TYC 2187-512-1 is found to harbor a planet with a minimum
mass of 0.33MJup in a near-circular 692-day orbit. The companion of
TZ Ari has a minimum mass of 0.21MJup, orbital period of 771d, and
orbital eccentricity of 0.46. We provide an overview of all known
giant planets in the CARMENES sample, from which we infer an
occurrence rate of giant planets orbiting M dwarfs with periods up to
2 years in the range between 2% to 6%. TZ Ari b is only the second
giant planet discovered orbiting a host with mass less than
0.3M☉. These objects occupy an extreme location in the planet
mass versus host mass plane. It is difficult to explain their
formation in core-accretion scenarios, so they may possibly have been
formed through a disk fragmentation process.
Description:
Radial-velocity time series from the CARMENES spectrograph at visible
and near-infrared wavelengths, including formal uncertainties.
Objects:
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RA (2000) DE Designation(s)
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21 22 06.28 +22 55 53.1 TYC 2187-512-1 = Karmn J21221+229
02 00 12.96 +13 03 07.0 TZ Ari = Karmn J02002+130
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tyc-vis.dat 23 94 Visible-light RV data of TYC 2187-512-1
tyc-nid.dat 23 96 Near-IR RV data of TYC 2187-512-1
tz-vis.dat 23 93 Visible-light RV data of TZ Ari
tz-nir.dat 23 89 Near-IR RV data of TZ Ari
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Byte-by-byte Description of file: tyc-nid.dat tyc-vis.dat tz-nir.dat tz-vis.dat
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Bytes Format Units Label Explanations
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1- 10 F10.5 d Date Date (BJD-2450000)
12- 17 F6.2 m/s RV Radial velocity
19- 23 F5.2 m/s e_RV Formal radial velocity uncertainty
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Acknowledgements:
Andreas Quirrenbach, A.Quirrenbach(at)lsw.uni-heidelberg.de
(End) Patricia Vannier [CDS] 30-Mar-2022