Two Earth-mass planets orbiting a red dwarf—the star called GJ 1002—, have been found recently by an international team of astronomers. The study is led by researchers from the Instituto de Astrofísica de Canarias (IAC) and has the participation of members of the Institute of Space Studies of Catalonia (IEEC  — Institut d’Estudis Espacials de Catalunya) and the Institute of Space Sciences (ICE-CSIC). The article has been accepted for publication in the journal Astronomy & Astrophysics.

The new planets orbit the nearby star GJ 1002, located less than 16 light years away from the solar system. Both have masses like the Earth and are located within the habitable zone of their star. As the star is quite cool, the habitable zone of the system is very close to it. The inner planet, GJ 1002 b, takes just 10 days to complete a full orbit. The other one, GJ 1002 c, needs 21 days.

This discovery has only been possible thanks to the collaboration between the ESPRESSO and CARMENES consortia, both devoted to the search of exoplanets. The star GJ 1002 was observed by the CARMENES instrument at the Calar Alto Observatory between 2017 and 2019, and later between 2019 and 2021 by the ESPRESSO instrument at the Paranal Observatory.

The infographic compares the planet positions, scaled to the habitability zone, with those of the Solar System. / Credits: Alejandro Suárez Mascareño (with resources from NASA)

"Nature seems determined to prove that Earth-like exoplanets are very common. With these two, we already know about 7 of them in nearby systems", explains Alejandro Suárez Mascareño, researcher at the Instituto de Astrofísica de Canarias and lead author of the study.

The closeness of the star to our solar system makes the planets around GJ 1002 excellent candidates for atmospheric characterization by studying their reflected light or thermal emission.

"These will be prime targets for future space missions such as LIFE, currently in concept phase and with the participation of the IEEC, which will be able to detect key molecules in their atmospheres and study the presence of a biosphere", explains Ignasi Ribas, a researcher from IEEC and the Institute of Space Sciences (ICE - CSIC).

Due to its cool temperature, GJ 1002 is too faint in visible light to study its radial velocity variations with most spectrographs. The design of CARMENES, much redder than most other spectrographs focused on radial velocities, made it possible to study it with the 3.5-m Calar Alto telescope. The combination of ESPRESSO and the collecting power of the 8-m VLT telescopes made it possible to obtain radial velocity measurements with a precision of 30 cm/s, out of reach for almost any other facility in the world.

Press release prepared by the Institute of Space Studies of Catalonia (IEEC) in collaboration with the Communication Office of the Instituto de Astrofísica de Canarias (IAC).