Located regarding 15 light years away, two new super-Earths have just been discovered by a team of astronomers. Orbiting around a red dwarf star, they are located in the habitable zone and are good candidates for an in-depth atmospheric study!
Will we soon find extraterrestrial life? While waiting to answer this question, astronomers are looking for worlds whose conditions would be favorable to life. Two new elements have just been added to the already long list of possibly habitable worlds: superterres located around a red dwarf star, GJ 1002, or Gliese 1002. Their discovery has just been published in the journal Astronomy & Astrophysics.
Located 15.78 light-years away in the constellation of the Whale, the star GJ 1002 has a mass of approximately 0.12 solar masses, for a radius of 0.137 solar radius. Nothing unusual for a woman rouge. But what interests researchers is that GJ 1002 is “one of the few known nearby systems with planets that might potentially host habitable environments”, explain the researchers.
Two new potentially habitable exoplanets in a system near us
The two new worlds were discovered using the radial velocity method. It consists of scrutinizing the radial velocity of the central star, and looking for variations, however small they may be. If it shelters planets, then those exert a gravitational influence on it, which leads it to revolve around a center of gravity different from its center of mass.
Looking at his light spectrum, it is possible to observe a shift towards red if it is moving away, or towards blue if it is approaching. The researchers then probe the spectrum of the star, and deduce the presence of an object which disturbs it gravitationally. This is what the researchers did, using the Espresso and Carmenes spectrographs, the first being located on the VLT (Very Large Telescope) from ESO, Chile, and the second at the Calar Alto Observatory, Spain.
By combining 139 spectra collected between 2017 and 2021, they identified at least two exoplanets in the GJ 1002 system. Named GJ 1002b and GJ 1002c, they are both super-Earths, rocky planets with a mass similar to that of Earth. The first has a mass of 1.08 Earth masses and goes around its star in 35 days. The other has a mass of 1.36 Earth masses and orbits its star in 21.2 days. And above all, they are both located in the habitable zone!
Atmospheric studies needed for GJ 1002c
According to the researchers, GJ 1002c would be the most suitable for further studies. Indeed, the study explains that “the proximity of the host star to the Sun makes the angular sizes of the two planets’ orbits large enough that their atmospheres can be studied via high-resolution, high-contrast spectroscopy with instruments such as the future Andes spectrograph or the Life mission “. And since the angular size of GJ 1002c exceeds that of GJ 1002b, it would be easier to probe.
The study concludes on the possible presence of a third planet, which would also be located in the habitable zone, in the outer part. But a much more distant and much more massive! “Gaia DR3 data shows excess astrometric noise, which might indicate a massive companion with large orbital separation”describe the scientists.
