e-Article
Gliese 12 b, A Temperate Earth-sized Planet at 12 Parsecs Discovered with TESS and CHEOPS
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Working Paper
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Dholakia, Shishir; Palethorpe, Larissa; Venner, Alexander; Mortier, Annelies; Wilson, Thomas G.; Huang, Chelsea X.; Rice, Ken; Van Eylen, Vincent; Nabbie, Emma; Cloutier, Ryan; Boschin, Walter; Ciardi, David; Delrez, Laetitia; Dransfield, Georgina; Ducrot, Elsa; Essack, Zahra; Everett, Mark E.; Gillon, Michaël; Hooton, Matthew J.; Kunimoto, Michelle; Latham, David W.; López-Morales, Mercedes; Li, Bin; Li, Fan; McDermott, Scott; Murphy, Simon; Murray, Catriona A.; Seager, Sara; Timmermans, Mathilde; Triaud, Amaury; Turner, Daisy A.; Twicken, Joseph D.; Vanderburg, Andrew; Wang, Su; Wittenmyer, Robert A.; Wright, Duncan
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Abstract
We report on the discovery of Gliese 12 b, the nearest transiting temperate, Earth-sized planet found to date. Gliese 12 is a bright ($V=12.6$ mag, $K=7.8$ mag) metal-poor M4V star only $12.162\pm0.005$ pc away from the Solar System with one of the lowest stellar activity levels known for an M-dwarf. A planet candidate was detected by TESS based on only 3 transits in sectors 42, 43, and 57, with an ambiguity in the orbital period due to observational gaps. We performed follow-up transit observations with CHEOPS and ground-based photometry with MINERVA-Australis, SPECULOOS, and Purple Mountain Observatory, as well as further TESS observations in sector 70. We statistically validate Gliese 12 b as a planet with an orbital period of $12.76144\pm0.00006$ days and a radius of $1.0\pm{0.1}$ R$_\oplus$, resulting in an equilibrium temperature of $\sim$315K. Gliese 12 b has excellent future prospects for precise mass measurement, which may inform how planetary internal structure is affected by the stellar compositional environment. Gliese 12 b also represents one of the best targets to study whether Earth-like planets orbiting cool stars can retain their atmospheres, a crucial step to advance our understanding of habitability on Earth and across the Galaxy.
Comment: 19 pages, 7 figures, Accepted for publication in MNRAS, Authors Shishir Dholakia and Larissa Palethorpe contributed equally
Comment: 19 pages, 7 figures, Accepted for publication in MNRAS, Authors Shishir Dholakia and Larissa Palethorpe contributed equally