The TASSIE program II: Three close-in companions orbiting sun-like stars
Abstract
Abstract We present three southern transiting giant planet candidates alerted by the Transiting Exoplanet Survey Satellite (TESS) mission and investigated at the University of Tasmania Greenhill Observatory (UTGO). The candidate planets are orbiting thin disk G-dwarf main-sequence stars with roughly solar metallicity, possessing orbital periods between 2.9 and 3.3 days and radii of 1.1–1.3 upper R Subscript upper J RJ $R_{J}$ . We performed ground-based follow-up photometry primarily with the UTGO Harlingten 50 cm, then gathered reconnaissance spectra, high angular resolution imaging, and high-precision radial velocities to rule out false positive scenarios. We confirmed that two of these systems host true exoplanets and constrained their masses. TOI-3053b is a typical hot Jupiter, with upper M Subscript 3053 b Baseline equals 0.85 plus or minus 0.12 M3053b=0.85±0.12 $M_{3053b} = 0.85 \pm 0.12$ M Subscript upper J J $_{J}$ and a bulk density of rho Subscript 3053 b Baseline equals 0.64 plus or minus 0.10 ρ3053b=0.64±0.10 $\rho_{3053b} = 0.64 \pm 0.10$ g cm Superscript negative 3 −3 $^{-3}$ . TOI-3278b/HATS-78b is a hot Saturn-mass planet ( upper M Subscript 3278 b Baseline equals 0.30 plus or minus 0.07 M3278b=0.30±0.07 $M_{3278b} = 0.30 \pm 0.07$ upper M Subscript upper J MJ $M_{J}$ ) with a highly inflated atmosphere and a low density of rho Subscript 3278 b Baseline equals 0.21 plus or minus 0.05 ρ3278b=0.21±0.05 $\rho_{3278b} = 0.21 \pm 0.05$ g cm Superscript negative 3 −3 $^{-3}$ . The other candidate (TOI-3272.01) remains unconfirmed, but appears consistent with being a hot Jupiter. TOI-3272.01 is notable as a candidate planet orbiting a potentially young to intermediate age star, with a rotational analysis indicating an age estimate of upper T 3272 equals 1.1 plus or minus 0.2 T3272=1.1±0.2 $T_{3272} = 1.1 \pm 0.2$ Gyr. These systems add to a growing sample of hot giant planets from TESS that may provide constraints on the migration pathways and radius inflation of the broader close-in exoplanet population.