Japan Geoscience Union Meeting 2018

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[JJ] Oral

P (Space and Planetary Sciences) » P-AE Astronomy & Extrasolar Bodies

[P-AE20] Exoplanet

Thu. May 24, 2018 9:00 AM - 10:30 AM 304 (3F International Conference Hall, Makuhari Messe)

convener:Masahiro Ikoma(Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo), Norio Narita(University of Tokyo), Chairperson:Ikoma Masahiro(The University of Tokyo), Narita Norio(University of Tokyo)

9:00 AM - 9:15 AM

[PAE20-01] Origin of Close-in Super-Earths Having Atmospheres: Effects of Planetary Migration and Disk Evolution

★Invited Papers

*Yasunori Hori1, Masahiro Ogihara2 (1.Astrobiology Center, National Institutes of Natural Sciences, 2.National Astronomical Observatory)

Keywords:Super-Earth, Planet formation, Planetary migration

Close-in super-Earths are common among over 3,700 exoplanets. Most of them have low mean-densities, which means the existence of an atmosphere onto a core; if some of them possess hydrogen-rich, namely, primordial atmospheres, their atmospheres likely originated from a disk gas. Two ideas for the origin of short-period low-mass planets having atmospheres have been proposed so far: in-situ formation, including giant impacts, and Type I migration. Based on both scenarios, we have investigated a theoretical relationship between planetary mass/semi-major axis and the final mass fraction of a H2/He atmosphere accreted from a prtoplanetary disk. In this talk, we discuss whether observed super-Earths can have/retain the primordial atmospheres.