We report the discovery of an Earth-sized planet in the habitable zone of a low-mass star called Kepler-1649. The planet, Kepler-1649 c, is 1.06−0.10+0.15 times the size of Earth and transits its 0.1977 +/- 0.0051 Msun mid M-dwarf host star every 19.5 days. It receives 74 +/- 3 % the incident flux of Earth, giving it an equilibrium temperature of 234 +/- 20K and placing it firmly inside the circumstellar habitable zone. Kepler-1649 also hosts a previously-known inner planet that orbits every 8.7 days and is roughly equivalent to Venus in size and incident flux. Kepler-1649 c was originally classified as a false positive by the Kepler pipeline, but was rescued as part of a systematic visual inspection of all automatically dispositioned Kepler false positives. This discovery highlights the value of human inspection of planet candidates even as automated techniques improve, and hints that terrestrial planets around mid to late M-dwarfs may be more common than those around more massive stars.
@article{arxiv.2004.06725,
title = {A Habitable-Zone Earth-Sized Planet Rescued from False Positive Status},
author = {Andrew Vanderburg and Pamela Rowden and Steve Bryson and Jeffrey Coughlin and Natalie Batalha and Karen A. Collins and David W. Latham and Susan E. Mullally and Knicole D. Colón and Chris Henze and Chelsea X. Huang and Samuel N. Quinn},
journal= {arXiv preprint arXiv:2004.06725},
year = {2020}
}
Comments
11 pages, 3 figures, 1 table. Accepted for publication in ApJL