NASA scientists have confirmed the discovery of first Earth-size planet on adequate distance from its star, making it a habitable zone. NASA’s Transiting Exoplanet Survey Satellite (TESS) found that the conditions on the exoplanet, named TOI 700 d, may just allow the presence of liquid water on the surface.
According to NASA, TOI 700 is a small, cool ‘M dwarf’ star located just over 100 light-years away in the southern constellation Dorado. It carries 40 percent of Sun’s mass and has half of its surface temperature. It was originally misclassified as being more similar to Sun which meant the planets would have been hotter and larger than they really are. The error was identified with the help of several researchers and a high school student, Alton Spencer, working with the TESS team.
“When we corrected the star’s parameters, the sizes of its planets dropped, and we realized the outermost one was about the size of Earth and in the habitable zone,” said Emily Gilbert, a graduate student at the University of Chicago.
“Additionally, in 11 months of data we saw no flares from the star, which improves the chances TOI 700 d is habitable and makes it easier to model its atmospheric and surface conditions,” she added.
The findings were presented at the 235th meeting of the American Astronomical Society in Honolulu and three papers were submitted to scientific journals. TOI 700 d is the outermost planet of the system which completes its orbit every 37 days and receives, from its star, 86 per cent of the energy that the Sun provides to Earth. It is believed that all the planets of the system are tidally locked to their star, meaning they rotate once per orbit. This phenomenon keeps one side constantly bathed in daylight.
Joseph Rodriguez, an astronomer at the Center for Astrophysics, said that it’s a great addition to the legacy of a mission that helped confirm two of the TRAPPIST-1 planets and identify five more. “Given the impact of this discovery - that it is TESS’s first habitable-zone Earth-sized planet - we really wanted our understanding of this system to be as concrete as possible,” he said.