An Earth-sized Planet On The Verge Of Tidal Disruption
TOI-6255~b (GJ 4256) is an Earth-sized planet (1.079±0.065 R⊕) with an orbital period of only 5.7 hours. With the newly commissioned Keck Planet Finder (KPF) and CARMENES spectrographs, we determined the planet’s mass to be 1.44±0.14 M⊕.
The planet is just outside the Roche limit, with Porb/PRoche = 1.13 ±0.10. The strong tidal force likely deforms the planet into a triaxial ellipsoid with a long axis that is ∼10% longer than the short axis. Assuming a reduced stellar tidal quality factor Q′⋆≈107, we predict that tidal orbital decay will cause TOI-6255 to reach the Roche limit in roughly 400 Myr.
Such tidal disruptions may produce the possible signatures of planet engulfment that have been on stars with anomalously high refractory elemental abundances compared to its conatal binary companion. TOI-6255 b is also a favorable target for searching for star-planet magnetic interactions, which might cause interior melting and hasten orbital decay.
TOI-6255 b is a top target (Emission Spectroscopy Metric of about 24) for phase curve observations with the James Webb Space Telescope.
Precise mass and radius measurements of exoplanets < 1.8R⊕ (from NASA Exoplanet Archive) and theoretical massradius relationships (Zeng et al. 2019). The ultra-short-period planets (Porb < 1 day, Rp < 1.8R⊕ blue points) are so strongly irradiated that they should be bare rocky bodies devoid of H/He envelopes. The existing sample of ultra-short-period planets are dominated by super-Earths (> 2M⊕). As an ensemble, they cluster around an Earth-like 30%Fe-70%MgSiO3 composition (Dai et al. 2019). TOI-6255 b is in the domain of Earth-sized planets. TOI-6255 b has a CMF of 45 ± 32% (red diamond). If accounting for the tidal distortion with a Love number h2 = 1, the inferred CMF drops to CMF of 31 ± 30% because during transit the shorter two axes of the ellipsoidal planet are visible (brown diamond). See Section 5.2 for details. — astro-ph.EP
Fei Dai, Andrew W. Howard, Samuel Halverson, Jaume Orell-Miquel, Enric Palle, Howard Isaacson, Benjamin Fulton, Ellen M. Price, Mykhaylo Plotnykov, Leslie A. Rogers, Diana Valencia, Kimberly Paragas, Michael Greklek-McKeon, Jonathan Gomez Barrientos, Heather A. Knutson, Erik A. Petigura, Lauren M. Weiss, Rena Lee, Casey L. Brinkman, Daniel Huber, Gudmundur Steffansson, Kento Masuda, Steven Giacalone, Cicero X. Lu, Edwin S. Kite, Renyu Hu, Eric Gaidos, Michael Zhang, Ryan A. Rubenzahl, Joshua N. Winn, Te Han, Corey Beard, Rae Holcomb, Aaron Householder, Gregory J. Gilbert, Jack Lubin, J. M. Joel Ong, Alex S. Polanski, Nicholas Saunders, Judah Van Zandt, Samuel W. Yee, Jingwen Zhang, Jon Zink, Bradford Holden, Ashley Baker, Max Brodheim, Ian J. M. Crossfield, William Deich, Jerry Edelstein, Steven R. Gibson, Grant M. Hill, Sharon R Jelinsky, Marc Kassis, Russ R. Laher, Kyle Lanclos, Scott Lilley, Joel N. Payne, Kodi Rider, Paul Robertson, Arpita Roy, Christian Schwab, Abby P. Shaum, Martin M. Sirk, Chris Smith, Adam Vandenberg, Josh Walawender, Sharon X. Wang, Shin-Ywan (Cindy)Wang, Edward Wishnow, Jason T. Wright, Sherry Yeh, Jos. A. Caballero, Juan C. Morales, Felipe Murgas, Evangelos Nagel, Ansgar Reiners, Andreas Schweitzer, Hugo M. Tabernero, Mathias Zechmeister, Alton Spencer, David R. Ciardi, Catherine A. Clark, Michael B. Lund, Douglas A. Caldwell, Karen A. Collins, Richard P. Schwarz, Khalid Barkaoui, Cristilyn N. Watkins, Avi Shporer, Norio Narita, Akihiko Fukui, Gregor Srdoc, David W. Latham, Jon M. Jenkins, George R. Ricker, Sara Seager, Roland Vanderspek
Comments: 18 pages, 7 figures, 5 tables, accepted to AAS Journals. The first RV mass measurement from the Keck Planet Finder
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2407.21167 [astro-ph.EP] (or arXiv:2407.21167v1 [astro-ph.EP] for this version)
Submission history
From: Fei Dai
[v1] Tue, 30 Jul 2024 20:14:12 UTC (2,436 KB)
https://arxiv.org/abs/2407.21167
Astrobiology,
