An ultra-short-period super-Earth with an extremely high density and an outer companion

Livingston, John H.; Gandolfi, Davide; Trani, Alessandro A.; Herath, Mahesh; Barragán, Oscar; Hatzes, Artie; Luque, Rafael; Fukui, Akihiko; Nowak, Grzegorz; Palle, Enric; Hellier, Coel; Fridlund, Malcolm; de Leon, Jerome; Hirano, Teruyuki; Narita, Norio; Albrecht, Simon; Dai, Fei; Deeg, Hans; Van Eylen, Vincent; Korth, Judith; Tamura, Motohide

Abstract

We present the discovery and characterization of a new multi-planetary system around the Sun-like star K2-360 (EPIC 201595106). K2-360 was first identified in K2 photometry as the host of an ultra-short-period (USP) planet candidate with a period of 0.88 d. We obtained follow-up transit photometry, confirming the star as the host of the signal. High precision radial velocity measurements from HARPS and HARPS-N confirm the transiting USP planet and reveal the existence of an outer (non-transiting) planet with an orbital period of ∼10 d. We measure a mass of 7.67±0.75 M⊕ and a radius of 1.57±0.08 R⊕ for the transiting planet, yielding a high mean density of 11±2 g cm-3, making it the densest well-characterized USP super-Earth discovered to date. We measure a minimum mass of 15.2±1.8 M⊕ for the outer planet, and explore a migration formation pathway via the von Zeipel–Kozai–Lidov (ZKL) mechanism and tidal dissipation.

Citation

Livingston, J. H., Gandolfi, D., Trani, A. A., Herath, M., Barragán, O., Hatzes, A., Luque, R., Fukui, A., Nowak, G., Palle, E., Hellier, C., Fridlund, M., de Leon, J., Hirano, T., Narita, N., Albrecht, S., Dai, F., Deeg, H., Van Eylen, V., Korth, J., & Tamura, M. (in press). An ultra-short-period super-Earth with an extremely high density and an outer companion. Scientific Reports, 14(1), Article 27219. https://doi.org/10.1038/s41598-024-76490-y

• Journal Article Type: Article
• Acceptance Date: Oct 14, 2024
• Online Publication Date: Nov 8, 2024
• Deposit Date: Nov 11, 2024
• Journal: Scientific Reports
• Electronic ISSN: 2045-2322
• Publisher: Nature Publishing Group
• Peer Reviewed: Peer Reviewed
• Volume: 14
• Issue: 1
• Article Number: 27219
• DOI: https://doi.org/10.1038/s41598-024-76490-y
• Public URL: https://keele-repository.worktribe.com/output/974387
• Publisher URL: https://www.nature.com/articles/s41598-024-76490-y