J/A+A/689/A132 AU Mic radial velocity curves (Mallorquin+, 2024)
Revisiting the dynamical masses of the transiting planets in the young AU Mic
system: Potential AU Mic b inflation at ∼20 Myr.
Mallorquin M., Bejar V.J.S., Lodieu N., Zapatero Osorio M.R., Yu H.,
Suarez Mascareno A., Damasso M., Sanz-Forcada J., Ribas I., Reiners A.,
Quirrenbach A., Amado P.J., Caballero J.A., Aigrain S., Barragan O.,
Dreizler S., Fernandez-Martin A., Goffo E., Henning T., Kaminski A.,
Klein B., Luque R., Montes D., Morales J.C., Nagel E., Palle E., Reffert S.,
Schlecker M., Schweitzer A
<Astron. Astrophys. 689, A132 (2024)>
=2024A&A...689A.132M 2024A&A...689A.132M (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Exoplanets ; Radial velocities ;
Infrared ; Optical
Keywords: techniques: spectroscopic - techniques: radial velocities -
planets and satellites: general -
planets and satellites: individual: AU Mic b -
planets and satellites: individual: AU Mic c - stars: low-mass
Abstract:
Understanding planet formation is important in the context of the
origin of planetary systems in general and of the Solar System in
particular, as well as to predict the likelihood of finding Jupiter,
Neptune, and Earth analogues around other stars.
We aim to precisely determine the radii and dynamical masses of
transiting planets orbiting the young M star AUMic using public
photometric and spectroscopic datasets.
We performed a joint fit analysis of the TESS and CHEOPS light curves
and more than 400 high-resolution spectra collected with several
telescopes and instruments. We characterise the stellar activity and
physical properties (radius, mass, density) of the transiting planets
in the young AUMic system through joint transit and radial velocity
fits with Gaussian processes.
We determine a radius of Rbp=4.79±0.29R⊕, a mass of
Mbp=9.0±2.7M⊕, and a bulk density of
ρbp=0.49±0.16g/cm3 for the innermost transiting planet
AUMic b. For the second known transiting planet, AUMic c, we infer a
radius of Rcp=2.79±0.18R⊕ , a mass of
Mcp=14.5±3.4M⊕_ , and a bulk density of
ρcp=3.90±1.17g/cm3. According to theoretical models, AUMic
b may harbour an H2 envelope larger than 5% by mass, with a fraction
of rock and a fraction of water. AUMic c could be made of rock and/or
water and may have an H2 atmosphere comprising at most 5% of its mass.
AUMic b has retained most of its atmosphere but might lose it over
tens of millions of years due to the strong stellar radiation, while
AUMic c likely suers much less photo-evaporation because it lies at a
larger separation from its host. Using all the datasets in hand, we
determine a 3 upper mass limit of M[d]psini=8.6M⊕ for the
AUMic 'd' TTV-candidate. In addition, we do not confirm the recently
proposed existence of the planet candidate AUMic 'e' with an
orbital period of 33.4 days.We investigated the level of the radial
velocity variations and show that it is lower at longer wavelength
with smaller changes from one observational campaign to another.
Description:
The spectroscopic and/or RV data presented in this paper are
available in public databases and/or have been published previously.
The star AU Mic was observed 98 times with the Calar Alto
high-Resolution search for M dwarfs with Exoearths with Near infrared
and optical Echelle Spectrographs (CARMENES) with the visible (VIS)
and NIR chan nels, in two observing campaigns during 2019 and 2020
(Ribas et al., 2023A&A...670A.139R 2023A&A...670A.139R, Cat J/A+A/670/A139).
There are 197 public spectra of AUMic in the ESO archive
(https://archive.eso.org/wdb/wdb/adp/phase3_spectral/form) collected
with the High Accuracy Radial velocity Planet Searcher (HARPS).
A total of 185 RVs secured with the SPectropolarimetre InfraROUge
(SPIRou) during four campaigns over a three year
baseline (2019-2022) were analysed and published by Donati et al.
(2023MNRAS.525..455D 2023MNRAS.525..455D).
Objects:
----------------------------------------------
RA (2000) DE Designation(s)
----------------------------------------------
20 45 09.53 -31 20 27.2 AU Mic = TOI-2221
----------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tablec1.dat 26 86 AU Mic CARMENES VIS RV analyzed in this work
tablec2.dat 26 87 AU Mic CARMENES NIR RV analyzed in this work
tablec3.dat 26 86 AU Mic HARPS RV analyzed in this work
tablec4.dat 26 176 AU Mic SPIRou RV analyzed in this work
--------------------------------------------------------------------------------
See also:
J/A+A/654/A159 : CHEOPS photometry of Au Mic b transits in 2020 (Szabo+, 2021)
J/AJ/162/137 : Minerva-Australis radial velocity of AU Mic (Addison+, 2021)
J/A+A/659/L7 : AU Mic b and c transits with CHEOPS (Szabo+, 2022)
J/AJ/164/110 : HST/COS far-UV spectra of AU Mic flares (Feinstein+, 2023)
J/A+A/682/A170 : AU Mic dynamic spectra of 42 radio observations (Bloot+, 2024)
Byte-by-byte Description of file: tablec?.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 F12.4 d Time Barycentric Julian date
14- 20 F7.2 m/s RV Radial velocity
22- 26 F5.2 m/s e_RV Radial velocity error
--------------------------------------------------------------------------------
Acknowledgements:
Manuel Mallorquin, manuel.mallorquin.diaz(at)iac.es
(End) Patricia Vannier [CDS] 08-Aug-2024