Exoplanetology: Exoplanets & Exomoons

The GAPS Programme at TNG. LXI. Atmospheric Parameters and Elemental Abundances of TESS Young Exoplanet Host Stars

By Keith Cowing
Status Report
astro-ph.SR
September 5, 2024
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The GAPS Programme at TNG. LXI. Atmospheric Parameters and Elemental Abundances of TESS Young Exoplanet Host Stars
Lithium abundance and equivalent width vs Teff plots. Left: non-LTE Li abundance, log ǫ(Li), versus effective temperature, Teff. The targets of this work (blue filled dots) are plotted together with the targets from Biazzo et al. (2022) in grey open squares and the members of the Pleiades (∼100 Myr; Sestito & Randich 2005), Hyades (∼600 Myr; Cummings et al. 2017), and M67 (∼4.5 Gyr; Pasquini et al. 2008) clusters (in yellow crosses, red diamonds, and green triangles, respectively). Right: lithium equivalent width (EWLi) versus effective temperature. Here, the empirical model isochrones by Jeffries et al. (2023) at 50, 100, 150, 200, 300, 400, 500, 600, 700, 800, 900 Myr, 1, 1.5, and 2 G. — astro-ph.SR

The study of exoplanets at different evolutionary stages can shed light on their formation, migration, and evolution. The determination of exoplanet properties depends on the properties of their host stars. It is therefore important to characterise the host stars for accurate knowledge on their planets.

Our final goal is to derive, in a homogeneous and accurate way, the stellar atmospheric parameters and elemental abundances of ten young TESS transiting planet-hosting GK stars followed up with the HARPS-N at TNG spectrograph within the GAPS programme. We derived stellar kinematic properties, atmospheric parameters, and abundances of 18 elements. Lithium line measurements were used as approximate age estimations.

We exploited chemical abundances and their ratios to derive information on planetary composition. Elemental abundances and kinematic properties are consistent with the nearby Galactic thin disk.

All targets show C/O<0.8 and 1.0<Mg/Si<1.5, compatible with silicate mantles made of a mixture of pyroxene and olivine assemblages. The Fe/Mg ratios, with values of ∼0.7-1.0, show a propensity for the planets to have big (iron) cores. All stars hosting very low-mass planets show Mg/Si values consistent with the Earth values, thus demonstrating their similar mantle composition. Hot Jupiter host stars show a lower content of O/Si, which could be related to the lower presence of water content.

We confirm a trend found in the literature between stellar [O/Fe] and total planetary mass, implying an important role of the O in shaping the mass fraction of heavy elements in stars and their disks. The detailed host star abundances provided can be employed for further studies on the composition of the planets within the current sample, when their atmospheres will be exploited.

S. Filomeno, K. Biazzo, M. Baratella, S. Benatti, V. D’Orazi, S. Desidera, L. Mancini, S. Messina, D. Polychroni, D. Turrini, L. Cabona, I. Carleo, M. Damasso, L. Malavolta, G. Mantovan, D. Nardiello, G. Scandariato, A. Sozzetti, T. Zingales, G. Andreuzzi, S. Antoniucci, A. Bignamini, A.S. Bonomo, R. Claudi, R. Cosentino, A.F.M. Fiorenzano, S. Fonte, A. Harutyunyan, C. Knapic

Comments: Accepted for publication on A&A. Abstract abridged
Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2409.00675 [astro-ph.SR] (or arXiv:2409.00675v1 [astro-ph.SR] for this version)
https://doi.org/10.48550/arXiv.2409.00675
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Submission history
From: Simone Filomeno
[v1] Sun, 1 Sep 2024 09:38:15 UTC (518 KB)
https://arxiv.org/abs/2409.00675

Astrobiology

Keith Cowing

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻

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