Japan Geoscience Union Meeting 2018

Presentation information

[JJ] Oral

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

[P-AE20] Exoplanet

Thu. May 24, 2018 10:45 AM - 12:15 PM 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)

12:00 PM - 12:15 PM

[PAE20-12] Feasibility Study for Detecting Atomic Oxygen Exospheres of Trappist-1 d, e, f, and Proxima b Using World Space Observatory – Ultraviolet (WSO-UV) Telescope

*Osada Naoya1, Shingo Kameda1, Hitoshi Fujiwara2, Go Murakami3, Masahiro Ikoma4, Keigo Enya5, Norio Narita6 (1.School of Science, Rikkyo University, 2.Faculty of Sience and Technology, Seikei University, 3.Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 4.Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 5.Japan Aerospace Exploration Agency, 6.The University of Tokyo)

Keywords:exoplanet, WSO-UV, exosphere

We present simulation results for the detectability of atomic oxygen exospheres on TRAPPIST-1d, e, f and Proxima b with WSO-UV telescope, assuming Earth-like atmospheres composed of nitrogen and oxygen. These atmospheres are exposed to Stellar extreme ultraviolet (EUV) radiation, 10 – 117 nm, several dozen times stronger than exposure to the present Earth because of star proximity (Bourrier et al., 2017, Ribas et al., 2017). It has been hypothesized that a thermosphere expands under extreme solar EUV radiation (Kulikov et al., 2007), which plays an important role in the ionization, dissociative ionization, dissociation, and heating of the planetary upper atmospheres. Furthermore, these responses depend on wavelength. However, stellar radiations between 40 and 91.2 nm cannot be measured because of the absorption of neutral hydrogen in an interstellar medium. We estimate the EUV spectrum at TRAPPIST-1d, e, f and Proxima b using empirically derived relationships between total hydrogen Lyman alpha intensity, at 122 nm, and the EUV spectrum presented by Linsky et al. (2014). We simulate the oxygen column density on these planets using the 1-Dimensional General Circulation Model (1DGCM) and estimate the necessary transit times to detect these planets using WSO-UV telescope. Moreover, we introduce the ultraviolet spectrometer which we propose onboard WSO-UV.