An international scientific team led by the Instituto de Astrofísica de Canarias (IAC), in Spain, has discovered two Earth-mass planets in orbit around the star GJ 1002, and in the habitable zone of this red dwarf close to the Solar System . “Nature seems determined to show us that terrestrial planets are very common. With these two, we already know of 7 in planetary systems very close to the Sun,” Alejandro Suárez, IAC researcher and lead author of the study accepted for publication in Astronomy & Astrophysics, explained in a statement on Thursday.
The new planets orbit around the star GJ 1002, located at a distance of less than 16 light years from the Solar System.
Both have masses similar to that of the Earth and are in the habitable zone of their star and the IAC points out that GJ 1002 b, the inner planet, takes just over 10 days to complete an orbit around its star while GJ 1002 c, for its part, needs a little more than 21 days. GJ 1002 is a red dwarf with just one eighth of the mass of the Sun and it is a rather cold and weak star, which means that its habitable zone is very close to the star, indicated Vera María Passegger, co-author of the article and researcher of the IAC.
The star’s closeness to the Solar System makes the two planets, especially GJ 1002 c, excellent candidates for characterizing their atmospheres on the basis of light reflection or thermal emission, the astrophysics institute added. “The future ANDES spectrograph for the ESO ELT telescope, in which the IAC participates, will be able to study the presence of oxygen in the atmosphere of GJ 1002 c”, explained Jonay González, IAC researcher and co-author of the work. Both planets also meet all the characteristics to become targets of the future LIFE space mission, currently under study.
“Due to its low temperature, the visible light of GJ 1002 is too dim to measure its variations in radial velocity with most spectrographs,” said Ignasi Ribas, a researcher at the Institute of Space Sciences (ICE-CSIC) and director of the Institute. d’Estudis Espacials de Catalunya (IEEC). CARMENES has a sensitivity to a wide range of wavelengths in the near infrared, superior to that of other spectrographs dedicated to detecting speed variations in the movement of stars, which allowed it to study GJ 1002 from the 3.5-meter telescope at Calar Tall.
The combination of ESPRESSO and the light-gathering power of the 8-meter-diameter VLT telescopes made it possible to obtain measurements with a precision of just 30 cm/s, unattainable by almost any other instrument in the world. “Either of the two groups would have had a lot of difficulties if they had tackled this work independently. Together we were able to go much further than we would have done separately,” said Alejandro Suárez.