Astronomers have discovered two potentially habitable worlds orbiting a red dwarf star in the cosmic backyard. The planets outside our solar system, or “exoplanets,” are only 16 light-years away and have masses similar to those of our planet.
It is located in the “habitable zone” of its star, GJ 1002, which is defined as the atmosphere around the star is neither too hot nor too cold to support liquid water, a vital ingredient for life.
“Nature seems intent on showing that Earth-like planets are very common,” study author Alejandro Suarez Mascareño of the Instituto Astrophysica de Canarias (IAC) said in a statement. (Opens in a new tab). “With those two, we now know of seven in planetary systems very close to the sun.”
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Because liquid water is essential to the existence of life, planets in the habitable zones are the focus of our search for life elsewhere in the universe, although just being in a habitable zone does not guarantee the ability to support life. For example, in the solar system, Venus and Mars are both in the Sun’s habitable zone but neither can currently support life.
Since GJ 1002 is a relatively cool red dwarf, its habitable zone—and these two new exoplanets—are much closer to it than Earth is to the Sun. The innermost planet, GJ 1002b, takes only about 10 days to orbit the star while the outer planet, GJ 1002c, completes its orbit in 21 days.
“GJ 1002 is a red dwarf star, barely one-eighth the mass of the Sun,” Vera Maria Pasegger, study co-author and researcher at IAC, said in the release. “It’s a fairly cool, dim star. That means its habitation zone is very close to the star.”
The proximity of both planets to Earth means they can be excellent targets for astronomers aiming to study the atmospheres of Earth-like worlds outside the solar system.
The exoplanets were discovered as a result of a collaboration between the European Southern Observatory (ESO) ESPRESSO instrument (Echelle Spectrograph for Rocky Exoplanets and Stable Spectral Observation) installed in the Very Large Telescope (VLT) in the Atacama Desert region of northern Chile, and CARMENES (High Resolution Search of Calar Alto). on M dwarfs with Exoearts with near-infrared and optical spectrometers (Échelle Spectrographs) at the Calar Alto Observatory in Andalusia, southern Spain.
The two instruments observed the planet’s parent star during two separate periods, Carmens studied GJ 1002 between 2017 and 2019, while Espresso collected data on the red dwarf between 2019 and 2021.
Carmen’s sensitivity over a wide range of near-infrared wavelengths makes it well-suited for detecting variations in the velocities of stars that can indicate orbiting planets.
“Because of its low temperature, the visible light from GJ 1002 is too faint for its velocity differences to be measured with the majority of spectrometers,” explained researcher at the Space Science Institute (ICE-CSIC) Ignasi Ribas.
While ESPRESSO and the light-gathering power of the VLT allowed astronomers to make observations of the system that were not possible with any other Earth-based telescope, it was the combination of these two powerful instruments that produced results that would otherwise be isolated from each other. I struggled to achieve the discovery of these exoplanets.
“Neither group would have faced many difficulties if they had tackled this work independently,” Suarez-Mascarino concluded. “Jointly we have been able to achieve far beyond what we would have done independently.”
Astronomers now hope to use the ANDES spectrometer on the Very Large Telescope under construction in GJ 1002c’s atmosphere.
The team’s research is published in the journal Astronomy and astrophysics. (Opens in a new tab)
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