Graduate School of Arts and Sciences, The University of Tokyo

Graduate School of Science, The University of Tokyo

Summary

An international research team, which includes Professor Noriyasu Narita of the Institute of Engineering Innovation, Graduate School of Arts and Sciences, The University of Tokyo, and Assistant Professor Akihiko Fukui of the Department of Earth and Planetary Science, Graduate School of Sciences, has developed a new method to observe planets in the solar system by combining the transit planet search satellite TESS, launched by NASA in April 2018, with simultaneous multi-colored Through the collaboration of multicolor transit observations using the MuSCAT2 imaging camera and other instruments, and line-of-sight velocity observations that can measure the mass of a planet, the team discovered the planet Gliese 486 b orbiting the red dwarf star Gliese 486, which is about 26 light years away from the solar system.

The observations revealed that Gliese 486 b is a terrestrial planet with a mass about 2.8 times that of the Earth and a radius about 1.3 times that of the Earth, and is mainly composed of rocks like the Earth. The planet has an orbital period of only 1.467 days and a surface temperature estimated to be over 400 degrees Celsius, making it an inhospitable environment for life. However, the short orbital period and high temperature are very favorable features for studying the composition and temperature distribution of the planet's atmosphere by means of "transit spectroscopy" and "secondary eclipse spectroscopy. In particular, since Gliese 486 b is located near the solar system, it is expected to be an important target for future observations as an Earth-like exoplanet where planetary atmospheres can be studied in detail.

The research results were published in Science, a scientific journal published by the American Association for the Advancement of Science, at 14:00 EST on March 4, 2021 (4:00 AM JST).

Figure: Image of the planetary surface of Gliese 486 b. (Image: RenderArea, https://renderarea.com/)

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