Dr. Rabus, Markus

We report the discovery of two short-period massive giant planets from NASA's Transiting Exoplanet Survey Satellite (TESS). Both systems, TOI-558 (TIC 207110080) and TOI-559 (TIC 209459275), were identified from the 30 minute cadence full-frame images and confirmed using ground-based photometric and spectroscopic follow-up observations from TESS's follow-up observing program working group. We find that TOI-558 b, which transits an F-dwarf (M* = ${1.349}_{-0.065}^{+0.064}$ M⊙, R* = ${1.496}_{-0.040}^{+0.042}$ R⊙, Teff = ${6466}_{-93}^{+95}$ K, age ${1.79}_{-0.73}^{+0.91}$ Gyr) with an orbital period of 14.574 days, has a mass of 3.61 ± 0.15 MJ, a radius of ${1.086}_{-0.038}^{+0.041}$ RJ, and an eccentric (e = ${0.300}_{-0.020}^{+0.022}$) orbit. TOI-559 b transits a G dwarf (M* = 1.026 ± 0.057 M⊙, R* = ${1.233}_{-0.026}^{+0.028}$ R⊙, Teff = ${5925}_{-76}^{+85}$ K, age ${6.8}_{-2.0}^{+2.5}$ Gyr) in an eccentric (e = 0.151 ± 0.011) 6.984 days orbit with a mass of ${6.01}_{-0.23}^{+0.24}$ MJ and a radius of ${1.091}_{-0.025}^{+0.028}$ RJ. Our spectroscopic follow up also reveals a long-term radial velocity trend for TOI-559, indicating a long-period companion. The statistically significant orbital eccentricity measured for each system suggests that these planets migrated to their current location through dynamical interactions. Interestingly, both planets are also massive (>3 MJ), adding to the population of massive giant planets identified by TESS. Prompted by these new detections of high-mass planets, we analyzed the known mass distribution of hot and warm Jupiters but find no significant evidence for multiple populations. TESS should provide a near magnitude-limited sample of transiting hot Jupiters, allowing for future detailed population studies.

The relative rarity of giant planets around low-mass stars compared with solar-type stars is a key prediction from the core-accretion planet formation theory. In this paper we report on the discovery of four gas giant planets that transit low-mass late K and early M dwarfs. The planets HATS-74Ab (TOI 737b), HATS-75b (TOI 552b), HATS-76b (TOI 555b), and HATS-77b (TOI 730b) were all discovered from the HATSouth photometric survey and follow-up using TESS and other photometric facilities. We use the new ESPRESSO facility at the VLT to confirm systems and measure their masses. We find that these planets have masses of 1.46 ± 0.14 MJ, 0.491 ± 0.039 MJ, 2.629 ± 0.089 MJ, and 1.374 0.0740.100-+ MJ, respectively, and radii of 1.032 ± 0.021 RJ, 0.884 ± 0.013 RJ, 1.079 ± 0.031 RJ, and 1.165 ± 0.021 RJ, respectively. The planets all orbit close to their host stars with orbital periods ranging from 1.7319 days to 3.0876 days. With further work, we aim to test core-accretion theory by using these and further discoveries to quantify the occurrence rate of giant planets around low-mass host stars.