[P-EM11] Exoplanet

[PEM11-P20] Development of a new optical multi-band simultaneous camera (MuSCAT4) and narrow-band filter to investigate the opacity of the exoplanet atmosphere

*Kiyoe Kawauchi¹, Norio Narita¹, Akihiko Fukui¹, The MuSCAT team (1.The University of Tokyo)

Keywords:exoplanet, instrument, opacity

Many discovered exoplanets are nearby stars (hot Jupiter, sub-Neptune, and super-Earth) and do not exist in our solar system. Especially, hot Jupiters can be relatively easily investigated because of their large signal and a few dozen atmospheres of hot Jupiters have already been investigated and revealed these characterizations. However, many atmospheres have muted spectra due to clouds and/or haze and only less than 7 % of all investigated hot Jupiters have a clear atmosphere (Wakeford et al. 2019). To investigate the atmosphere efficiently with future space telescopes (e.g. ARIEL) and ground-based telescopes (e.g. TMT), we should search for clear atmospheres suited to the investigation of atmospheric composition and structure first. The sodium absorption feature is one of the most important key opacity sources because it is thought to be the cause of generally low albedos (Seager & Sasselov 2000; Brown 2001; Barman et al. 2001; Hubbard et al. 2001).
Therefore, we have developed narrow-band filters to search for the opacity of exoplanet atmospheres using the Na absorption feature mounted with a third and fourth optical multi-band simultaneous camera (MuSCAT3, MuSCAT4) in Hawaii and Australia. We will introduce their characteristics of them and our scientific goals using them.

In addition, we have already an optical multi-band simultaneous camera (MuSCAT, MuSCAT2, and MuSCAT3) for 2m class telescopes in the Northern hemisphere and published some scientific performances on the validation and characterization of exoplanets. To do the same scientific observation in the Southen hemisphere, we have developed a new optical multi-band simultaneous camera (MuSCAT4) on the 2m telescope operated by Las Cumbres Observatory and located at Siding Spring Observatory in Australia. We also show the specification of MuSCAT4.