TOI 700d. All separate letters—this name designates an exoplanet discovered by NASA in January 2020. Which may as well be an eternity for our small humanity affected by the Covid-19 virus. In the heart of the Dorado constellation, 100 light years away, the existence of TOI 700d was recorded by the Transitory Exoplanet Survey Satellite (TESS) sent into space in 2018 to locate celestial bodies the size of our planet and to measure their brightness. While TOI 700d’s mass and radius are quite similar to those of Earth, its rotation around its star, a red dwarf with a spectral type of MV, requires only thirty-seven days. It has shown no sign of eruption to date, but it will be a long time before we know, with any precision, its light spectrum, which is to say the stellar flux emitted at this star’s surface. The observation of these fluxes generally makes it possible to determine in a partial way a planet’s composition and thus to start to obtain a representation.

Fabien Danesi