| Description: |
Populating the exoplanet mass–radius diagram in order to identify the underlying relationship that governs planet composition is driving an interdisciplinary effort within the exoplanet community. The discovery of hot super-Earths—a high-temperature, short-period subset of the super-Earth planet population—has presented many unresolved questions concerning the formation, evolution, and composition of rocky planets. We report the discovery of a transiting, ultra-short-period hot super-Earth orbiting TOI-1075 (TIC351601843), a nearby (d = 61.4 pc) late-K/early-M-dwarf star, using data from the Transiting Exoplanet Survey Satellite. The newly discovered planet has a radius of 1.791${}_{-0.081}^{+0.116}$ R⊕ and an orbital period of 0.605 day (14.5 hr). We precisely measure the planet mass to be 9.95${}_{-1.30}^{+1.36}$ M⊕ using radial velocity measurements obtained with the Planet Finder Spectrograph mounted on the Magellan II telescope. Our radial velocity data also show a long-term trend, suggesting an additional planet in the system. While TOI-1075 b is expected to have a substantial H/He atmosphere given its size relative to the radius gap, its high density (${9.32}_{-1.85}^{+2.05}$ g cm−3) is likely inconsistent with this possibility. We explore TOI-1075 b's location relative to the M-dwarf radius valley, evaluate the planet's prospects for atmospheric characterization, and discuss potential planet formation mechanisms. Studying the TOI-1075 system in the broader context of ultra-short-period planetary systems is necessary for testing planet formation and evolution theories and density-enhancing mechanisms and for future atmospheric and surface characterization studies via emission spectroscopy with the JWST. |
| Relation: |
https://eprints.keele.ac.uk/id/eprint/12284/1/Essack_2023_AJ_165_47.pdf; Essack, Z, Shporer, A, Burt, JA, Seager, S, Cambioni, S, Lin, Z, Collins, KA, Mamajek, EE, Stassun, KG, Ricker, GR, Vanderspek, R, Latham, DW, Winn, JN, Jenkins, JM, Butler, RP, Charbonneau, D, Collins, KI, Crane, JD, Gan, T, Hellier, C orcid:0000-0002-3439-1439 , Howell, SB, Irwin, J, Mann, AW, Ramadhan, A, Shectman, SA, Teske, JK, Yee, SW, Mireles, I, Quintana, EV, Tenenbaum, P, Torres, G and Furlan, E (2023) TOI-1075 b: A Dense, Massive, Ultra-short-period Hot Super-Earth Straddling the Radius Gap. The Astronomical Journal, 165 (2). |