CORALIE radial-velocity search for companions around evolved stars (CASCADES)

Ottoni, G.; Udry, S.; Ségransan, D.; Buldgen, G.; Eggenberger, P.; Pezzotti, C.; Adibekyan, V.; Marmier, M.; Mayor, M.; Santos, N. C.; Sousa, S. G.; Lagarde, N.; Charbonnel, C.

doi:10.1051/0004-6361/202040078

Cited by 6 publications

(1 citation statement)

References 99 publications

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“…At the same time, some planets in a far orbit can survive after the host star expansion, and recent disco v eries show that giant stars do indeed have planetary systems (see e.g. Ottoni et al 2022 ;Teng et al 2022 ).…”

Section: Discussion a N D C O N C L U S I O Nmentioning

confidence: 99%

Chemical properties of the central part of the Galactic nuclear stellar disc. Abundances in four classical Cepheids revisited

Kovtyukh

Коротин

Andrievsky

et al. 2022

Monthly Notices of the Royal Astronomical Society

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This paper is a revised abundance analysis of four yellow supergiant stars Cepheids which are located in the Galactic nucleus. The results are based on the spectra secured with the help of Subaru telescope, which are of the better quality comparing to previously analyzed spectra taken with the Infra Red Telescope Facility. A significantly improved method of the effective temperature determination of program stars, which is based on the calibrating relations between the temperature and line depth ratios, was applied. The present results confirmed our previous finding about the solar metallicity level at the Galaxy center. It is very likely that the four stars of our program were born from an interstellar medium having homogeneous chemical properties, since all the stars are located close to each other, have close pulsation periods, and hence the age. However, one of the stars has a somewhat increased abundances of all studied elements compared to the abundance in the other three stars. A possible reason of this fact is discussed.

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Section: Discussion a N D C O N C L U S I O Nmentioning

confidence: 99%

Chemical properties of the central part of the Galactic nuclear stellar disc. Abundances in four classical Cepheids revisited

Kovtyukh

Коротин

Andrievsky

et al. 2022

Monthly Notices of the Royal Astronomical Society

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CORALIE radial velocity search for companions around evolved stars (CASCADES)

Buldgen

Ottoni

Pezzotti

et al. 2022

A&A

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Context. The advent of asteroseismology as the golden path to precisely characterize single stars naturally led to synergies with the field of exoplanetology. Today, the precise determination of stellar masses, radii and ages for exoplanet-host stars is a driving force in the development of dedicated software and techniques to achieve this goal. However, as various approaches exist, it is clear that they all have advantages and inconveniences and that there is a trade-off between accuracy, efficiency, and robustness of the techniques. Aims. We aim to compare and discuss various modelling techniques for exoplanet-host red giant stars for which TESS data are available. The results of the seismic modelling are then used to study the dynamical evolution and atmospheric evaporation of the planetary systems. Methods. We study, in detail, the robustness, accuracy and precision of various seismic modelling techniques when applied to four exoplanet-host red giants observed by TESS. We discuss the use of global seismic indexes, the use of individual radial frequencies and that of non-radial oscillations. In each case, we discuss the advantages and inconveniences of the modelling technique. Results. We determine precise and accurate masses of exoplanet-host red giant stars orbited by long-period Jupiter-like planets using various modelling techniques. For each target, we also provide a model-independent estimate of the mass from a mean density inversion combined with radii values from Gaia and spectroscopic data. We show that no engulfment or migration is observed for these targets, even if their evolution is extended beyond their estimated seismic ages up the red giant branch.

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CORALIE radial-velocity search for companions around evolved stars (CASCADES)

Pezzotti

Ottoni

Buldgen

et al. 2022

A&A

Self Cite

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Context. Increasing the number of detected exoplanets is far from anecdotal, especially for long-period planets that require a long duration of observation. More detections imply a better understanding of the statistical properties of exoplanet populations, and detailed modelling of their host stars also enables thorough discussions of star–planet interactions and orbital evolution of planetary systems. Aims. In the context of the discovery of a new planetary system, we aim to perform a complete study of HD 29399 and its companion by means of radial-velocity measurements, seismic characterisation of the host-star, and modelling of the orbital evolution of the system. Methods. High-resolution spectra of HD 29399 were acquired with the CORALIE spectrograph mounted on the 1.2-m Swiss telescope located at La Silla Observatory (Chile) as part of the CASCADES survey. We used the moments of the cross-correlation function profile as well as the photometric variability of the star as diagnostics to distinguish between stellar and planetary-induced signals. To model the host star we combined forward modelling with global and local minimisation approaches and inversion techniques. We also studied the orbital history of the system under the effects of both dynamical and equilibrium tides. Results. We present the detection of a long-period giant planet. Combining these measurements with photometric observations by TESS, we are able to thoroughly model the host star and study the orbital evolution of the system. We derive stellar and planetary masses of 1.17 ± 0.10 M⊙ and 1.59 ± 0.08 MJup, respectively, and an age for the system of 6.2 Gyr. We show that neither dynamical nor equilibrium tides have been able to affect the orbital evolution of the planet. Moreover, no engulfment is predicted for the future evolution of the system.

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CORALIE radial-velocity search for companions around evolved stars (CASCADES)

Cited by 6 publications

References 99 publications

Chemical properties of the central part of the Galactic nuclear stellar disc. Abundances in four classical Cepheids revisited

Chemical properties of the central part of the Galactic nuclear stellar disc. Abundances in four classical Cepheids revisited

CORALIE radial velocity search for companions around evolved stars (CASCADES)

CORALIE radial-velocity search for companions around evolved stars (CASCADES)

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