2015/11/30 by Erik A. Petigura, Andrew W. Howard, Eric D. Lopez +13 · 43 citations
Earth and Planetary Sciences · Physics and Astronomy · #Astro and Planetary Science #Astronomy #Astrophysics #Exoplanet #High-pressure geophysics and materials #Physics #Planet #Saturn #Stellar, planetary, and galactic studies #Super-Earth #Transit (satellite) #astro-ph.EP
paper · pdf · doi:10.3847/0004-637x/818/1/36
published in The Astrophysical Journal 818(1), 36 (IOP Publishing) · 12 pages, 6 figures, 3 tables, published in ApJ. v2: text updated to ApJ version, replaced EPIC-2037 with K2-24
openalex publication_date 2016/02/04 · arxiv created 2016/06/09 · arxiv updated 2016/06/10 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
ABSTRACT We report the discovery and confirmation of K2-24 b and c, two sub-Saturn planets orbiting a bright ( V = 11.3), metal-rich ([Fe/H] = 0.42 ± 0.04 dex) G3 dwarf in the K2 Campaign 2 field. The planets are 5.68 ± 0.56 and 7.82 ± 0.72 and have orbital periods of 20.8851 ± 0.0003 days and 42.3633 ± 0.0006 days, near the 2:1 mean-motion resonance. We obtained 32 radial velocities with Keck/HIRES and detected the reflex motion due to K2-24 b and c. These planets have masses of 21.0 ± 5.4 and 27.0 ± 6.9 , respectively. With low densities of 0.63 ± 0.25 g cm −3 and 0.31 ± 0.12 g cm −3 , respectively, the planets require thick envelopes of H/He to explain their large sizes and low masses. Interior structure models predict that the planets have fairly massive cores of and , respectively. They may have formed exterior to their present locations, accreted their H/He envelopes at large orbital distances, and migrated in as a resonant pair. The proximity to resonance, large transit depths, and host star brightness offers rich opportunities for TTV follow-up. Finally, the low surface gravities of the K2-24 planets make them favorable targets for transmission spectroscopy by Hubble Space Telescope , Spitzer , and James Webb Space Telescope .