J/A+A/688/A14 HD 73344 RV and light curves (Sulis+, 2024)
A low-mass sub-Neptune planet transiting the bright active star HD 73344.
Sulis S., Crossfield I.J.M., Santerne A., Saillenfest M., Sousa S.,
Mary D., Aguichine A., Deleuil M., Delgado Mena E., Mathur S.,
Polanski A., Adibekyan V., Boisse I., Costes J.C., Cretignier M.,
Heidari N., Lebarbe C., Forveille T., Hara N., Meunier N., Santos N.,
Balcarcel-Salazar S., Cortes-Zuleta P., Dalal S., Gorjian V.,
Halverson S., Howard A.W., Kosiarek M.R., Lopez T.A., Martin D.V.,
Mousis O., Rajkumar B., Strom P.A., Udry S., Venot O., Willett E.
<Astron. Astrophys. 688, A14 (2024)>
=2024A&A...688A..14S 2024A&A...688A..14S (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Exoplanets ; Photometry ; Optical ;
Radial velocities
Keywords: planets and satellites: detection -
planets and satellites: fundamental parameters -
star: individual: TOI 5140 - star: individual: HD 73344
Abstract:
Planets with radii between 2 and 4R⊕ closely orbiting solar-type
stars, are crucial for studying the transition from rocky to giant
planets. These are prime targets for atmospheric characterization
using missions like JWST and ARIEL. Unfortunately, only a handful of
such planets with precise mass measurements are known to orbit bright
stars.
Our goal is to determine the mass of a transiting planet around
the very bright F6 star, HD 73344 (Vmag=6.9). This star exhibits high
activity and has a rotation period close to the planet's orbital
period (Pb=15.6-days).
The transiting planet, initially a K2 candidate, is confirmed through
TESS observations (TOI 5140.01). We refine its parameters using TESS
data and rule out a false positive with Spitzer observations. We
analyze high-precision radial velocity (RV) data from the SOPHIE and
HIRES spectrographs. We conduct separate and joint analyses of K2,
TESS, SOPHIE, and HIRES data using the PASTIS software. Given the
star's early type and high activity, we use a novel observing
strategy, targeting the star at high cadence for two consecutive
nights with SOPHIE to understand short-term stellar variability. We
model stellar noise with two Gaussian processes: one for rotationally
modulated stellar processes, one for short-term stellar variability.
High-cadence RV observations provide better constraints on stellar
variability and precise orbital parameters for the transiting planet:
a radius of Rb=2.98-0.07+0.08R⊕ and a mass of
Mb=2.98-1.90+2.50M⊕ (upper-limit at 3σ is
<10.48M⊕). The derived mean density suggests a
sub-Neptune-type composition, but uncertainties in the planet's mass
prevent a detailed characterization. In addition, we detect a
planetary candidate with a minimum mass of about
Mcsinic=116.3-13.0+12.8M⊕ and a period of
Pc=66.45±0.25_+0.10days in the RV data. Dynamical analyses
confirm the stability of the two-planet system and provide constraints
on the inclination of the candidate planet, which favours a
near-coplanar system.
While the transiting planet orbits a bright star at a short period,
stellar activity has prevented us from precise mass measurements
despite intensive RV follow-up. Long-term RV tracking of this planet
could improve this measurement, as well as our understanding of the
host star's activity. The latter will be essential if we are to
characterize the atmosphere of planets around F-type stars using
transmission spectroscopy.
Description:
K2, TESS, HIRES and SOPHIE observations of HD 73344.
K2 observed HD 73344 (EPIC 212178066) during campaign 16 (C16), which
ran from December 07, 2017 to February 25, 2018, and during campaign
18 (C18), which ran from May 12, 2018 to July 02, 2018.
The Transiting Exoplanets Survey Satellite (TESS) observed HD 73344
(TIC 175193677) in the red-optical bandpass (600-1100 nm) during
sector 45 (November 2021-December 2021) and sector 46 (December
2021-January 2022).
We observed HD 73344 with the high-resolution echelle spectrograph
SOPHIE at the Haute-Provence Observatory (OHP, France) as part of the
program dedicated to the RV follow-up of K2 planet candidates6. The
target was observed between 2018-11-02 and 2020-03-01, gathering 345
high-resolution spectra.
We obtained 238 additional RV data points with the HIRES spectrometer
installed at the Keck I telescope from 2018-03-17 to 2021-06-03.
Objects:
-------------------------------------------------------
RA (2000) DE Designation(s)
-------------------------------------------------------
08 38 45.52 +23 41 09.2 HD 73344 = TIC 175193677
-------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
k2.dat 33 3686 K2 light curve
tess.dat 33 35057 TESS light curve
hires.dat 33 188 HIRES radial velocities
sophddt.dat 33 203 SOPHIE radial velocities taken at short cadence
sophlong.dat 33 312 SOPHIE radial velocities
--------------------------------------------------------------------------------
Byte-by-byte Description of file: k2.dat tess.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 14 F14.6 d Time Baricentric Julian date (BJD)
17- 24 F8.6 --- RFlux Relative flux
26- 33 F8.6 --- e_RFlux Flux error
--------------------------------------------------------------------------------
Byte-by-byte Description of file: hires.dat sophddt.dat sophlong.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 14 F14.6 d Time Baricentric Julian date (BJD)
16- 24 F9.6 km/s RV Radial velocity
26- 33 F8.6 km/s e_RV Radial velocity error
--------------------------------------------------------------------------------
Acknowledgements:
Sophia Sulis, sophia.sulis(at)lam.fr
(End) Patricia Vannier [CDS] 25-May-2024