Speaker
Description
ESA’s PLATO mission will provide highly precise photometric data, necessitating equally accurate and consistent spectroscopic information to precisely characterise stars and their orbiting planets. Currently, many gas-giant exoplanet host stars in the PLATO southern prime field designated for the mission lack uniformly derived atmospheric and chemical parameters. This inconsistency in spectroscopic inferences introduce biases in stellar properties which propagate into uncertainties in their planetary companions. We perform a uniform spectroscopic analysis of 13 prime gas-giant exoplanet hosts using high-resolution optical spectra to derive their atmospheric parameters, such as Teff , log g, [Fe/H], and key velocity broadening parameters. Of the 13 stars analysed, we provide new detailed chemical abundances for seven, consequently expanding the scope of the existing dataset. The analysis also reveals notable chemical anomalies: TOI-481 in the turn-off phase shows an unusually high Lithium abundance, i.e. A(Li) ≈ 2.09, a finding that suggests a possible planet engulfment event, which contrasts with the typical Lithium depletion generally observed in planet-hosting stars. In addition, KELT-14 exhibits an elevated Mg/Si ratio of approximately 1.37, which suggests the presence of planets rich in pyroxene and olivine. Conversely, TOI-1338 displays a high C/O ratio of about 1.02, indicating a high carbon content; both of these values are significantly above those measured for the remaining stars in the sample. This study delivers a homogeneous spectroscopic and chemical-abundance dataset for gas-giant exoplanet hosts, providing essential reference parameters for the up-coming asteroseismic modelling and enhancing the accuracy of both stellar and planetary inferences.
| Stream | Science or Engineering |
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