Two small temperate planets transiting nearby M dwarfs in K2 campaigns 0 and 1
Article
Article Title | Two small temperate planets transiting nearby M dwarfs in K2 campaigns 0 and 1 |
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ERA Journal ID | 1057 |
Article Category | Article |
Authors | Schlieder, Joshua E. (Author), Crossfield, Ian J M (Author), Petigura, Erik A. (Author), Howard, Andrew W. (Author), Aller, Kimberly M. (Author), Sinukoff, Evan (Author), Isaacson, Howard T. (Author), Fulton, Benjamin J. (Author), Ciardi, David R. (Author), Bonnefoy, Mickael (Author), Ziegler, Carl (Author), Morton, Timothy D. (Author), Lepine, Sebastien (Author), Obermeier, Christian (Author), Liu, Michael C. (Author), Bailey, Vanessa P. (Author), Baranec, Christoph (Author), Beichman, Charles A. (Author), Defrere, Denis (Author), Henning, Thomas (Author), Hinz, Philip (Author), Law, Nicholas (Author), Riddle, Reed (Author) and Skemer, Andrew (Author) |
Journal Title | The Astrophysical Journal: an international review of astronomy and astronomical physics |
Journal Citation | 818 (1), pp. 87-101 |
Article Number | 87 |
Number of Pages | 15 |
Year | 2016 |
Publisher | IOP Publishing |
Place of Publication | United States |
ISSN | 0004-637X |
1538-4357 | |
Digital Object Identifier (DOI) | https://doi.org/10.3847/0004-637X/818/1/87 |
Web Address (URL) | http://iopscience.iop.org/article/10.3847/0004-637X/818/1/87/ |
Abstract | The prime Kepler mission revealed that small planets (<4⊕) are common, especially around low-mass M dwarfs. K2, the repurposed Kepler mission, continues this exploration of small planets around small stars. Here we combine K2 photometry with spectroscopy, adaptive optics imaging, and archival survey images to analyze two small planets orbiting the nearby field-age M dwarfs, K2-26 (EPIC 202083828) and K2-9. K2-26 is an M1.0 ± 0.5 dwarf at 93 ± 7 pc from K2 Campaign 0. We validate its planet with a day period of 14.5665 and estimate a radius of 2.67-0.42 +0.46 R⊕. K2-9 is an M2.5 ± 0.5 dwarf at 110 ± 12 pc from K2 Campaign 1. K2-9b was first identified by Montet et al.; here we present spectra and adaptive optics imaging of the host star and independently validate and characterize the planet. Our analyses indicate K2-9b is a 2.25-0.96 +0.53 R⊕ planet with a 18.4498 day period. K2-26b exhibits a transit duration that is too long to be consistent with a circular orbit given its measured stellar radius. Thus, the long transits are likely due to the photoeccentric effect and our transit fits hint at an eccentric orbit. Both planets receive low incident flux from their host stars and have estimated equilibrium temperatures <500 K. K2-9b may receive approximately Earth-like insolation. However, its host star exhibits strong GALEX UV emission which could affect any atmosphere it harbors. K2-26b and K2-9b are representatives of a poorly studied class of small planets with cool temperatures that have radii intermediate to Earth and Neptune. Future study of these systems can provide key insight into trends in bulk composition and atmospheric properties at the transition from silicate dominated to volatile rich bodies. |
Keywords | eclipses; stars; K2-26; K2-9;photometric; spectroscopic; |
Contains Sensitive Content | Does not contain sensitive content |
ANZSRC Field of Research 2020 | 510109. Stellar astronomy and planetary systems |
Public Notes | For access to this article, please click on the URL link provided. |
Institution of Origin | University of Southern Queensland |
Byline Affiliations | National Aeronautics and Space Administration (NASA), United States |
University of Arizona, United States | |
California Institute of Technology (Caltech), United States | |
University of Hawaii, United States | |
University of California, United States | |
Grenoble Alpes University, France | |
University of North Carolina, United States | |
Princeton University, United States | |
Georgia State University, United States | |
Max Planck Society, Germany | |
Stanford University, United States |
https://research.usq.edu.au/item/q4351/two-small-temperate-planets-transiting-nearby-m-dwarfs-in-k2-campaigns-0-and-1
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