Two 'habitable' Earth-like worlds found orbiting star not far from Solar System

Our galaxy might be full of liveable worlds like our own, after astronomers spotted another two Earth-like planets in the 'habitable zone' in a nearby star.

Researchers found two planets with Earth-like masses orbiting the star GJ 1002, a red dwarf that is less than 16 light years from the Solar System.

Red dwarf stars are small and cool in temperature, and are the most common type of star in our Milky Way galaxy.

Alejandro Suarez Mascareno, a researcher at the Instituto de Astrofisica de Canarias in the Canary Islands, said: "Nature seems bent on showing us that Earth-like planets are very common.

"With these two we now know seven in planetary systems quite near to the Sun."

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Both of the planets are in the habitable zone of their star, where the temperature is at a level that liquid water could exist.

GJ 1002b, the inner of the two, takes little more than 10 days to complete an orbit around the star, while GJ 1002c needs a little over 21 days.

Co-author Vera Maria Passegger said: "GJ 1002 is a red dwarf star, with barely one-eighth the mass of the Sun. It is quite a cool, faint star. This means that its habitable zone is very close to the star."

The researchers believe that it might be possible to detect the make-up of their atmospheres – including whether there is oxygen.

The proximity of the star to our Solar System implies that the two planets, especially GJ 1002c, could have their atmospheres analysed based either on their reflected light or on their thermal emission.

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The discovery was made thanks to a collaboration between the teams behind two planet-hunting spectrographs, Espresso and Carmenes.

GJ 1002 was observed by Carmenes between 2017 and 2019, and by Espresso between 2019 and 2021.

Only by using the two instruments together was it possible to measure the light from the planet.

Ignasi Ribas, researcher at the Institute of Space Sciences in Barcelona, said: "Because of its low temperature the visible light from GJ 1002 is too faint to measure its variations in velocity with the majority of spectrographs."

Carmenes has a sensitivity over a wide range of near-infrared wavelengths that is superior to those of other spectrographs aimed at detecting variations in the velocities of stars, and this allowed it to study GJ 1002 from the 3.5m telescope at Calar Alto Observatory in Almeria, Spain.