Three new brown dwarfs and a massive hot Jupiter revealed by TESS around early-type stars

Abstract

Context. The detection and characterization of exoplanets and brown dwarfs around massive AF-type stars is essential to investigate and constrain the impact of stellar mass on planet properties. However, such targets are still poorly explored in radial velocity (RV) surveys because they only feature a small number of stellar lines and those are usually broadened and blended by stellar rotation as well as stellar jitter. As a result, the available information about the formation and evolution of planets and brown dwarfs around hot stars is limited. Aims. We aim to increase the sample and precisely measure the masses and eccentricities of giant planets and brown dwarfs transiting early-type stars detected by the Transiting Exoplanet Survey Satellite (TESS). Methods. We followed bright (V < 12 mag) stars with T eff > 6200 K that host giant companions (R > 7 R ⊕ ) using ground-based photometric observations as well as high precision radial velocity measurements from the CORALIE, CHIRON, TRES, FEROS, and MINERVA-Australis spectrographs.Results. In the context of the search for exoplanets and brown dwarfs around early-type stars, we present the discovery of three brown dwarf companions, TOI-629b, TOI-1982b, and TOI-2543b, and one massive planet, TOI-1107b. From the joint analysis of TESS and ground-based photometry in combination with high precision radial velocity measurements, we find the brown dwarfs have masses between 66 and 68 M Jup , periods between 7.54 and 17.17 days, and radii between 0.95 and 1.11 R Jup . The hot Jupiter TOI-1107b has an orbital period of 4.08 days, a radius of 1.30 R Jup , and a mass of 3.35 M Jup . As a by-product of this program, we identified four low-mass eclipsing components (TOI-288b, TOI-446b, TOI-478b, and TOI-764b). Conclusions. Both TOI-1107b and TOI-1982b present an anomalously inflated radius with respect to the age of these systems. TOI-629 is among the hottest stars with a known transiting brown dwarf. TOI-629b and TOI-1982b are among the most eccentric brown dwarfs. The massive planet and the three brown dwarfs add to the growing population of well-characterized giant planets and brown dwarfs transiting AF-type stars and they reduce the apparent paucity.

HIP 33609 b: An Eccentric Brown Dwarf Transiting a V = 7.3 Rapidly Rotating B Star

“…HIP 33609 b joins a population of 37 transiting BDs published to date (Grieves et al 2021;Carmichael et al 2022;Psaridi et al 2022;Sebastian et al 2022), and is one of the most extreme substellar companions yet discovered. HIP 33609 not only has a precise age measurement of 150 ± 25 Myr, but is also the brightest and hottest host of a transiting BD discovered to date.…”

The TESS Grand Unified Hot Jupiter Survey. II. Twenty New Giant Planets*

“…We have confirmed and characterized 20 new short-period giant planets detected by the TESS mission, based on extensive ground-based photometric, spectroscopic, and imaging observations. These objects join a host of other giant planets that have been discovered by TESS over the last few years (e.g., Rodriguez et al 2019;Zhou et al 2019;Brahm et al 2020;Davis et al 2020;Nielsen et al 2020;Ikwut-Ukwa et al 2021;Rodriguez et al 2021;Sha et al 2021;Wong et al 2021;Knudstrup et al 2022;Psaridi et al 2022;Rodriguez et al 2022;Yee et al 2022), showcasing how TESS is rapidly transforming our knowledge of hot Jupiters by providing a uniform, all-sky sample of these planets. Yee et al (2021) found that the sample of known transiting hot Jupiters was only ∼40% complete at a magnitude-limit of G < 12.5.…”

The TESS Grand Unified Hot Jupiter Survey. I. Ten TESS Planets

“…We have confirmed and characterized twenty new short-period giant planets detected by the TESS mission, based on extensive ground-based photometric, spectroscopic, and imaging observations. These objects join a host of other giant planets that have been discovered by TESS over the last few years (e.g., Rodriguez et al 2019;Zhou et al 2019;Brahm et al 2020;Davis et al 2020;Nielsen et al 2020;Ikwut-Ukwa et al 2021;Rodriguez et al 2021;Sha et al 2021;Wong et al 2021;Knudstrup et al 2022;Rodriguez et al 2022;Psaridi et al 2022;Yee et al 2022), showcasing how TESS is rapidly transforming our knowledge of hot Jupiters by providing a uniform, all-sky sample of these planets. Yee et al (2021) found that the sample of known transiting hot Jupiters was only ∼ 40% complete at a magnitude-limit of G < 12.5.…”