[P-AE17] 系外惑星

[PAE17-P04] Current Status of UVSPEX onboard WSO-UV

*亀田 真吾¹、村上 豪²、平林 賢人¹、桑原 正輝¹、中山 陽史³、小玉 貴則³、生駒 大洋⁴、成田 憲保³、塩谷 圭吾²、寺田 直樹⁵ (1.立教大学理学部、2.JAXA、3.東京大学、4.国立天文台、5.東北大学)

キーワード：

系外惑星、宇宙望遠鏡、惑星大気

Many Earth-sized exoplanets have already been discovered, and several Earth-sized exoplanets were recently detected in the habitable zone around low-temperature stars near the solar system. Though it is still difficult to observe their lower atmospheres, it is relatively more feasible to observe their upper atmospheres. The expanded exospheres can be observed in UV during the exoplanet transit event in a primary eclipse. It reduces the stellar flux when an exoplanet is orbiting in front of the host star. We performed a preliminary design of Ultraviolet Spectrograph for Exoplanet (UVSPEX) for World Space Observatory Ultraviolet (WSO-UV), which is a 1.7-m UV space telescope prepared by Russia. The dominant requirements for the UVSPEX are as follows. The spectral resolution is better than 0.5 nm to separate O I line from other spectral lines. The spectral range is to exceed the wavelengths from 115 nm to 135 nm to detect at least H Lyman alpha 121.6nm to O I 130 nm. The throughput is better than 0.3%. We propose a simple spectrograph design to achieve these requirements, containing the slit, the concave (toroidal) grating as a dispersing element, and the imaging photo-detector. This optical concept is conventional and used in other space missions for UV spectroscopy. In this presentation, we show the configuration of the UVSPEX instrument and its science objectives.