Confirmation and characterisation of three giant planets detected by TESS from the FIES/NOT and Tull/McDonald spectrographs

TL;DR

This paper confirms and characterizes three Jupiter-sized exoplanets detected by TESS around G-type stars using ground-based spectrographs, providing detailed orbital and physical parameters and indicating potential outer companions.

Contribution

It presents the confirmation and detailed characterization of three new giant exoplanets with ground-based spectroscopy, including orbital parameters and evidence of additional companions.

Findings

Planets have periods of 4.9, 8.9, and 8.6 days.

Planet sizes range from 0.96 to 1.14 Jupiter radii.

Two systems show signs of outer companions.

Abstract

We report the confirmation and characterisation of TOI-1820~b, TOI-2025~b, and TOI-2158~b, three Jupiter-sized planets on short-period orbits around G-type stars detected by TESS. Through our ground-based efforts using the FIES and Tull spectrographs, we have confirmed these planets and characterised their orbits, and find periods of around $4.9$~d, $8.9$~d, and $8.6$~d for TOI-1820~b, TOI-2025~b, and TOI-2158~b, respectively. The sizes of the planets range from 0.96 to 1.14 Jupiter radii, and their masses are in the range from 0.8 to 4.4 Jupiter masses. For two of the systems, namely TOI-2025 and TOI-2158, we see a long-term trend in the radial velocities, indicating the presence of an outer companion in each of the two systems. For TOI-2025 we furthermore find the star to be well-aligned with the orbit, with a projected obliquity of $9^{+33}_{-31}$~$^\circ$. As these planets are all found in relatively bright systems (V$\sim$10.9-11.6 mag), they are well-suited for further studies, which could help shed light on the formation and migration of hot and warm Jupiters.