J/A+A/674/A44 TESS, CHEOPS and ESPRESSO data of HD 22946 (Garai+, 2023)
Refined parameters of the HD 22946 planetary system and the true orbital period
of planet d.
Garai Z., Osborn H.P., Gandolfi D., Brandeker A., Sousa S.G., Lendl M.,
Bekkelien A., Broeg C., Collier Cameron A., Egger J.A., Hooton M.J.,
Alibert Y., Delrez L., Fossati L., Salmon S., Wilson T.G., Bonfanti A.,
Tuson A., Ulmer-Moll S., Serrano L.M., Borsato L., Alonso R., Anglada G.,
Asquier J., Barrado y Navascues D., Barros S.C.C., Barczy T., Baumjohann W.,
Beck M., Beck T., Benz W., Billot N., Biondi F., Bonfils X., Buder M.,
Cabrera J., Cessa V., Charnoz S., Csizmadia Sz., Cubillos P.E., Davies M.B.,
Deleuil M., Demangeon O.D.S., Demory B.-O., Ehrenreich E., Erikson E.,
Van Eylen V., Fortier A., Fridlund M., Gillon M., Van Grootel V., Guedel M.,
Guenther M.N., Hoyer S., Isaak K.G., Kiss L.L., Kristiansen M.H., Laskar J.,
Lecavelier des Etangs A., Lovis C., Luntzer A., Magrin D., Maxted P.F.L.,
Mordasini C., Nascimbeni V., Olofsson G., Ottensamer R., Pagano I.,
Palle E., Peter G., Piotto G., Pollacco D., Queloz D., Ragazzoni R.,
Rando N., Rauer H., Ribas I., Santos N.C., Scandariato G., Segransan D.,
Simon A.E., Smith A.M.S., Steller M., Szabo Gy.M., Thomas N., Udry S.,
Venturini J., Walton, N.
<Astron. Astrophys. 674, A44 (2023)>
=2023A&A...674A..44G 2023A&A...674A..44G (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Exoplanets ; Space observations ;
Photometry ; Optical ; Radial velocities
Keywords: methods: observational - techniques: photometric -
planets and satellites: fundamental parameters
Abstract:
Multi-planet systems are important sources of information regarding
the evolution of planets. However, the long-period planets in these
systems often escape detection. These objects in particular may retain
more of their primordial characteristics compared to close-in
counterparts because of their increased distance from the host star.
HD 22946 is a bright (G=8.13mag) late F-type star around which
three transiting planets were identified via Transiting Exoplanet
Survey Satellite (TESS) photometry, but the true orbital period of the
outermost planet d was unknown until now.
We aim to use the Characterising Exoplanet Satellite (CHEOPS) space
telescope to uncover the true orbital period of HD 22946d and to
refine the orbital and planetary properties of the system, especially
the radii of the planets.
We used the available TESS photometry of HD22946 and observed several
transits of the planets b, c, and d using CHEOPS. We identified two
transits of planet d in the TESS photometry, calculated the most
probable period aliases based on these data, and then scheduled CHEOPS
observations. The photometric data were supplemented with ESPRESSO
(Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic
Observations) radial velocity data. Finally, a combined model was
fitted to the entire dataset in order to obtain final planetary and
system parameters.
Based on the combined TESS and CHEOPS observations, we successfully
determined the true orbital period of the planet d to be
47.42489±0.00011d, and derived precise radii of the planets in the
system, namely 1.362±0.040REarth, 2.328±0.039REarth, and
2.607±0.060 REarth for planets b, c, and d, respectively. Due to
the low number of radial velocities, we were only able to determine
3σ upper limits for these respective planet masses, which are
13.71MEarth, 9.72MEarth, and 26.57MEarth. We estimated that
another 48 ESPRESSO radial velocities are needed to measure the
predicted masses of all planets in HD 22946. We also derived stellar
parameters for the host star.
Planet c around HD 22946 appears to be a promising target for future
atmospheric characterisation via transmission spectroscopy. We can
also conclude that planet d, as a warm sub-Neptune, is very
interesting because there are only a few similar confirmed exoplanets
to date. Such objects are worth investigating in the near future, for
example in terms of their composition and internal structure.
Description:
We present here the detrended and normalised TESS and CHEOPS
photometry data of the HD 22946 planetary system, as well as the
normalised radial velocity observations of HD 22946 taken at ESPRESSO.
Objects:
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RA (2000) DE Designation(s)
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03 39 16.76 -42 45 45.1 HD 22946 = TOI-411
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
cheops.dat 37 3165 CHEOPS photometry of HD 22946
tess.dat 37 61687 TESS photometry of HD 22946
rv.dat 58 14 ESPRESSO radial velocities of HD 22946
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See also:
J/A+A/664/A156 : Young sub-Neptunes orbiting TOI-2076 light curves
(Osborn+, 2022)
Byte-by-byte Description of file: cheops.dat tess.dat
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Bytes Format Units Label Explanations
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1- 18 F18.10 d BJD Barycentric Julian date
20- 37 F18.16 --- Flux Relative flux
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Byte-by-byte Description of file: rv.dat
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Bytes Format Units Label Explanations
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1- 18 F18.10 d BJD Barycentric Julian date
20- 38 F19.16 --- RV Normalised Radial velocity
40- 58 F19.17 --- e_RV Normalised Radial velocity uncertainty (± 1-sigma)
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Acknowledgements:
Zoltan Garai, zgarai(at)gothard.hu
(End) Patricia Vannier [CDS] 24-Apr-2023