KOI-3158: The oldest known system of terrestrial-size planets
Abstract
The first discoveries of exoplanets around Sun-like stars have fueled efforts to find ever smaller worlds evocative of Earth and other terrestrial planets in the Solar System. While gas-giant planets appear to form preferentially around metal-rich stars, small planets (with radii less than four Earth radii) can form under a wide range of metallicities. This implies that small, including Earth-size, planets may have readily formed at earlier epochs in the Universe's history when metals were far less abundant. We report Kepler spacecraft observations of KOI-3158, a metal-poor Sun-like star from the old population of the Galactic thick disk, which hosts five planets with sizes between Mercury and Venus. We used asteroseismology to directly measure a precise age of 11.2+/-1.0 Gyr for the host star, indicating that KOI-3158 formed when the Universe was less than 20% of its current age and making it the oldest known system of terrestrial-size planets. We thus show that Earth-size planets have formed throughout most of the Universe's 13.8-billion-year history, providing scope for the existence of ancient life in the Galaxy.
Keywords
Cite
@article{arxiv.1501.07869,
title = {KOI-3158: The oldest known system of terrestrial-size planets},
author = {T. L. Campante and T. Barclay and J. J. Swift and D. Huber and V. Zh. Adibekyan and W. Cochran and C. J. Burke and H. Isaacson and E. V. Quintana and G. R. Davies and V. Silva Aguirre and D. Ragozzine and R. Riddle and C. Baranec and S. Basu and W. J. Chaplin and J. Christensen-Dalsgaard and T. S. Metcalfe and T. R. Bedding and R. Handberg and D. Stello and J. M. Brewer and S. Hekker and C. Karoff and R. Kolbl and N. M. Law and M. Lundkvist and A. Miglio and J. F. Rowe and N. C. Santos and C. Van Laerhoven and T. Arentoft and Y. P. Elsworth and D. A. Fischer and S. D. Kawaler and H. Kjeldsen and M. N. Lund and G. W. Marcy and S. G. Sousa and A. Sozzetti and T. R. White},
journal= {arXiv preprint arXiv:1501.07869},
year = {2015}
}
Comments
Submitted to EPJ Web of Conferences, to appear in the Proceedings of the 3rd CoRoT Symposium, Kepler KASC7 joint meeting; 4 pages, 1 figure