100 light years distant from Earth in the constellation Dorado is a planetary system called TOI 700, where TESS, the planet hunter satellite, has discovered TOI 700 d, the first Earth-size habitable zone planet.
The habitable zone of a star is the distance range where conditions may be suitable to allow the presence of liquid water on the surface. Scientists have confirmed the finding using NASA’s Spitzer Space Telescope.
Good news
TOI 700 d is one of the few Earth-size planets discovered so far in the habitable zone of a star. There are also planets in the TRAPPIST-1 system and other worlds discovered by NASA’s Kepler space telescope. Although other similar planets have been found, it is the first to be discovered by TESS, which was launched in 2018.
“TESS was designed and launched specifically to find Earth-size planets orbiting nearby stars. Planets around nearby stars are easier to track with larger telescopes in space and on Earth. Discovering TOI 700 d is a key scientific finding for TESS. Confirming planet size and habitable zone status with Spitzer is another victory for Spitzer as the end of science operations nears in January, “commented Paul Hertz, Division Director for Astrophysics at NASA headquarters in Washington.
The planet, 100 light-years away, is part of a multi-planet system around TOI 700, a cool little M-dwarf star in the constellation Dorado, which is visible from our southern hemisphere. By comparison, the closest star to us, Proxima Centauri, is 4.2 light years from Earth. The star is about 40% the mass and size of our sun, with half the surface temperature.
TOI 700 d is the outermost of the three planets, completing a single orbit around the star every 37 Earth days. It is 20% larger than Earth and from its smallest star, the planet receives about 86% of the energy that our sun supplies to Earth. And, apparently, scientists think that the planet is blocked by tides, so that one side of the world would always be in daylight.
In a simulation, NASA explained that the planet is covered in oceans with a “dense atmosphere dominated by carbon dioxide similar to what scientists suspect surrounded Mars when it was a young world.”
The problem
Despite the relatively large number of small exoplanet discoveries to date, most stars are between 600 and 3,000 light years away from Earth, which means they are too far away for detailed follow-up observation.
While we don’t know the exact conditions at TOI 700 d, NASA scientists say they can use what we do know, such as the size of the planet and the type of star it orbits, to make predictions about what is possible on this planet. newly discovered.
The new planetary system, in short
The innermost planet, called TOI 700 b, is about the size of Earth, is probably rocky, and completes one orbit every 10 days.
The central planet, TOI 700 c , is 2.6 times larger than Earth, orbits every 16 days, and is likely a gas-dominated world.
TOI 700 d, the outermost planet known in the system and the only one in the habitable zone, is 20% larger than Earth, orbits every 37 days and receives 86% of the energy that the Sun provides from its star. the earth.
Reference: NASA
