Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published April 14, 2014 | metadata_only
Journal Article

An Earth-Sized Planet in the Habitable Zone of a Cool Star


The quest for Earth-like planets is a major focus of current exoplanet research. Although planets that are Earth-sized and smaller have been detected, these planets reside in orbits that are too close to their host star to allow liquid water on their surfaces. We present the detection of Kepler-186f, a 1.11 ± 0.14 Earth-radius planet that is the outermost of five planets, all roughly Earth-sized, that transit a 0.47 ± 0.05 solar-radius star. The intensity and spectrum of the star's radiation place Kepler-186f in the stellar habitable zone, implying that if Kepler-186f has an Earth-like atmosphere and water at its surface, then some of this water is likely to be in liquid form.

Additional Information

© 2014, AAAS. 6 December 2013; accepted 12 March 2014. The authors working at NASA Ames thank the SETI Institute for hosting them during the U.S. government shutdown. E.V.Q. and J.F.R. acknowledge support from the Research Opportunities in Space and Earth Sciences Kepler Participating Scientist Program Grant NNX12AD21G. S.N.R.'s contribution was performed as part of the NASA Astrobiology Institute's Virtual Planetary Laboratory Lead Team, supported by NASA under cooperative agreement no. NNA13AA93A. D.H. acknowledges support by an appointment to the NASA Postdoctoral Program at the Ames Research Center, administered by Oak Ridge Associated Universities through a contract with NASA, and the Kepler Participating Scientist Program. The Center for Exoplanets and Habitable Worlds is supported by the Pennsylvania State University, the Eberly College of Science, and the Pennsylvania Space Grant Consortium. F.S. acknowledges support from the European Research Council (Starting Grant 209622: E3ARTHs). This paper includes data collected by the Kepler mission. Funding for the Kepler mission is provided by the NASA Science Mission directorate. This research also made use of NASA's Astrophysics Data System. Some of the data presented in this paper were obtained from the Mikulski Archive for Space Telescopes (MAST). The Space Telescope Science Institute is operated by the Association of Universities for Research in Astronomy, under NASA contract NAS5-26555. Support for MAST for non-Hubble Space Telescope data is provided by the NASA Office of Space Science via grant NNX13AC07G and by other grants and contracts. This research made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with NASA under the Exoplanet Exploration Program. The Gemini Observatory is operated by the Association of Universities for Research in Astronomy, under a cooperative agreement with the National Science Foundation (NSF) on behalf of the Gemini partnership: NSF (United States), the National Research Council (Canada), the Comisión Nacional de Investigación Científica y Tecnológica (Chile), the Australian Research Council (Australia), the Ministério da Ciência, Tecnologia e Inovação (Brazil), and the Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina).

Additional details

August 20, 2023
August 20, 2023