Another shipment of six short-period giant planets from TESS

Abstract

We present the discovery and characterization of six short-period, transiting giant planets from NASA’s Transiting Exoplanet Survey Satellite (TESS) — TOI-1811 (TIC 376524552), TOI-2025 (TIC 394050135), TOI-2145 (TIC 88992642), TOI-2152 (TIC 395393265), TOI-2154 (TIC 428787891), & TOI-2497 (TIC 97568467). All six planets orbit bright host stars (8.9 <G < 11.8, 7.7 <K < 10.1). Using a combination of time-series photometric and spectroscopic follow-up observations from the TESS Follow-up Observing Program (TFOP) Working Group, we have determined that the planets are Jovian-sized (RP = 0.99-1.45 RJ), have masses ranging from 0.92 to 5.26 MJ, and orbit F, G, and K stars (4766 ≤ Teff ≤ 7360 K). We detect a significant orbital eccentricity for the three longest-period systems in our sample: TOI-2025 b (P = 8.872 days, 0.394$^{+0.035}_{-0.038}$), TOI-2145 b (P = 10.261 days, e = $0.208^{+0.034}_{-0.047}$), and TOI-2497 b (P = 10.656 days, e = $0.195^{+0.043}_{-0.040}$). TOI-2145 b and TOI-2497 b both orbit subgiant host stars (3.8 < log g <4.0), but these planets show no sign of inflation despite very high levels of irradiation. The lack of inflation may be explained by the high mass of the planets; $5.26^{+0.38}_{-0.37}$ MJ (TOI-2145 b) and 4.82 ± 0.41 MJ (TOI-2497 b). These six new discoveries contribute to the larger community effort to use TESS to create a magnitude-complete, self-consistent sample of giant planets with well-determined parameters for future detailed studies.

TOI-1994b: A Low-mass Eccentric Brown Dwarf Transiting A Subgiant Star

“…The smaller sample of brown dwarfs with masses below 42.5 M J used in Ma & Ge (2014) followed the trend that the more massive a brown dwarf is, the lower eccentricity it tends to have. The lower-mass brown dwarf eccentricity distribution is also similar to giant planet eccentricity distributions in more recent papers, such as in Rodriguez et al (2023). Above 42.5 M J , the eccentricities of brown dwarf companions are more widely distributed.…”

“…Ma & Ge (2014) discovered that the brown dwarf population can be split at around 42.5 M J based on eccentricity. Lower-mass brown dwarfs display an eccentricity distribution consistent with massive planets (Rodriguez et al 2023), while higher-mass brown dwarfs have an eccentricity distribution similar to binary stars (Halbwachs et al 2003). This could suggest that brown dwarfs with mass <42.5M J form similar to planets in protoplanetary disks and >42.5M J form similarly to stellar binaries (although see Schlaufman (2018) for an alternate proposal to this boundary).…”

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

“…Rice et al (2022) suggest that this discontinuity may only exist for the low eccentricity population, a trend that would provide strong evidence for high-eccentricity migration as the dominant migration mechanism for hot Jupiters. This hypothesis is also supported by the current population of TESS discovered giant planets (Rodriguez et al 2023;Yee et al 2022). If BDs and giant planets undergo similar migratory processes, then they could exhibit the same discontinuity in stellar obliquity.…”