Discovery of an Earth-sized planet in an intriguing solar system
Credits: Artist's rendering of the exoplanet TOI 700 e. Credits: NASA/JPL-Caltech/Robert Hurt
NASA's TESS satellite has spotted its second planet similar in size to Earth. This world, which was discovered about 101 light years from Earth, around the same star as the first, may be capable of holding liquid water.
New planet for TESS
Launched a little over four years ago, the Transiting Exoplanet Survey Satellite (TESS) has already identified more than 280 confirmed planets (and several thousand candidates). One of the most intriguing is a world called TOI 700 d which was discovered in 2020 . This Earth-sized object is located in the habitable zone of its star, named TOI 700, which is approximately 101.4 light years from Earth . More recently, a team from the Jet Propulsion Laboratory identified the presence of a second similar planet also evolving in a zone allowing the maintenance of liquid water on the surface.
Note that TOI 700 is a red dwarf star . These objects, which make up about 75% of all stars in the Galaxy, are smaller and cooler than the Sun. On the other hand, they are generally much more active , releasing enormous plumes of plasma capable of destroying all hope of life in the surrounding area. However, unlike many of its peers, TOI 700 appears relatively quiet (no evidence of flares in two years of data). We could thus imagine conditions favorable to the emergence of living things .
TOI 700 is about 95% the size of Earth . The planet is therefore probably rocky. It orbits its star approximately once every 28 Earth days and only shows one side, like the Moon with the Earth.
Artist illustration of TOI 700 d. Credits: NASA Goddard Space Flight Center
A compact system
The system also has two other planets evolving closer to their star. We could thus make a comparison with the famous TRAPPIST-1 system , found only 39.5 light years from Earth and which is known to bring together seven Earth-sized planets. The TOI 700 system, although more distant, will on the other hand be easier to study since TRAPPIST-1 is a more active and dimmer star.
Researchers are currently observing the system with the Very Large Telescope in Chile using its Echelle Spectrograph for Rocky Exoplanets and Stable Spectroscopic Observations (ESPRESSO) instrument. The latter, designed to characterize exoplanets similar to Earth, could make it possible to determine the masses of the four planets in the system. The team also plans to use the James Webb Telescope and focus it on the largest of these planets, TOI 700 b.
This discovery once again shows the value of TESS's extended mission. The ship was initially supposed to operate for only two years. Its second mission extension, started last September, will lead it to continue its work until October 2024 .
Source: websites