NASA announced on Monday that its planet hunter TESS satellite has made it possible to discover a new planet the size of Earth and at a distance neither too close nor too far from its star for liquid water to be there (maybe).
The planet is called “TOI 700 d” and is relatively close to us: a hundred light-years away, announced the Nasa Jet Propulsion Laboratory at the winter conference of the American astronomical society in Honolulu, Hawaii. “TESS was designed and launched specifically to find planets the size of Earth and orbiting nearby stars, “ said Paul Hertz, director of the NASA astrophysics division.
The system was nearly missed by TESS, but several amateur astronomers, including a high school student by the name of Alton Spencer and praised by NASA, discovered an initial classification error, which helped to understand the true nature of the system. The discovery was then confirmed by the Spitzer space telescope.
A few other planets of a similar type have been discovered before, notably by the old Kepler space telescope, but this is the first by TESS, launched in 2018. TESS fixes part of the sky to detect if objects – planets – pass by. of stars, which causes a temporary drop in brightness of the star.
This allows TESS to infer the presence of a planet, its size, its orbit, etc. The TOI 700 star is small, about 40% the size and mass of our Sun, with a surface temperature less than half. TESS discovered three planets around this star, named TOI 700 b, c, and d.
Only the “d” is in the so-called habitable zone. It is almost the size of the Earth (20% more) and circles its star in 37 days. It receives 86% of the energy supplied by the Sun to the Earth. It remains to be seen what it is made of.
One of the simulations, says NASA, is a planet covered by oceans with “a dense atmosphere dominated by carbon dioxide, similar to what Mars looked like when it was young, according to scientists’ assumptions.” A face of this planet always faces its star, as is the case with the Moon with the Earth, a phenomenon called synchronous rotation.
This face would be constantly covered with clouds, according to this model. Another simulation predicts a version of the Earth without oceans, where the winds would blow from the hidden side towards the lit face. Multiple astronomers will now observe the planet with other instruments, obtaining new data that may correspond to one of the models predicted by NASA.