They discovered a potentially habitable exoplanet near Earth

An international study involving the Institute of Astrophysics of the Canary Islands (IAC) and the Center for Astrobiology (CAB, INTA-CSIC) has discovered the planet intermediate size between Earth and Venus in orbit cool red dwarf 40 light years away, in the constellation Pisces.

To discover it, data obtained from space and ground-based telescopes were combined: satellite Tess from NASA and other entities such as CARMEN THISat the Calar Alto Observatory (CAHA) and MuSKAT2installed on the Carlos Sánchez Telescope (TCS) at the Teide Observatory.

A new world called Gliese 12 b, is in the habitable zone of its star, making it a promising candidate for studying its atmosphere with the powerful James Webb Space Telescope. To date, it is the closest temperate exoplanet discovered by the transit method, that is, by observing the periodic dimming of its star caused by the passage of the planet.

The lower luminosity of red dwarfs means that their habitable zones (the range of orbital distances where liquid water can exist on a planet’s surface) are closer to them. This makes it easier to detect planets transiting in the habitable zones around red dwarfs than planets around stars that emit more energy.

Gliese 12 b is the closest Earth-sized temperate exoplanet discovered by the transit method.

The surface temperature of Gliese 12 b is estimated to be around 42°C. However, the final temperature will depend on whether that planet was able to maintain an atmosphere (and its composition) from its formation to the present.

The exoplanet orbits its host star Gliese 12, which is only 27% the size of the Sun and 60% of its surface temperature, every 12.8 days. The distance separating Gliese 12 from the exoplanet is 7% of the distance between Earth and the Sun, so it receives 1.6 times more energy from its star than our planet.

exovenus

“Although we still don’t know whether Gliese 12 b has an atmosphere, we think of it as an ‘exo-Venus’ whose size and energy derived from its star are similar to those of our planetary neighbor in the Solar System,” said He. speaks. Masayuki Kuzuharaa project associate professor at the Tokyo Astrobiology Center who leads the research team that just published their results in a journal. Letters from an Astrophysical Journal.

“Gliese 12 b represents one of the best targets for studying whether Earth-sized planets orbiting cool stars can retain their atmospheres, an important step for advancing our understanding of habitability on planets throughout our galaxy,” he says . Shishir Dholakiaastrophysicist from the University of Southern Queensland (Australia) and principal investigator of another group, which published its results in parallel and independently in the journal Monthly Notices of the Royal Astronomical Society.

Co-author of another study, Jose Antonio Caballero of CAB, adds: “And this is a critical step in advancing our understanding of the habitability of planets in our galaxy.”

“This is a unique candidate for new atmospheric studies that could help unravel some aspects of the evolution of our solar system,” he adds. Enric Palleone of the many MAK researchers involved in the discovery.

It is a unique candidate for new atmospheric studies that could help unravel some aspects of the evolution of our solar system.

Enric Palle
— Institute of Astrophysics of the Canary Islands (IAC)

“Although Earth and Venus are very similar planets in size and mass, their histories are very different. Earth is still habitable, but Venus is not due to the complete loss of water; The atmosphere of Gliese 12 b can teach us a lot about how atmospheric evolution and habitability conditions for terrestrial planets change as they evolve,” says the researcher.

An important factor in preserving the atmosphere is the stormy character of his staras we recently saw with the Sun and the Northern Lights, which we saw even in the Canary Islands.

Relatively quiet star

Red dwarfs tend to be magnetically active, resulting in frequent and powerful bursts of X-ray and ultraviolet radiation. However, analysis by both teams concluded that Gliese 12 shows no signs of extreme behavior. This makes this system an ideal candidate for studying its atmosphere with the James Webb Space Telescope.

Thanks to modern technology, you can use transit method to analyze the chemical composition of exoplanetary atmospheres. By studying the unique structure of the chemical fingerprints created when starlight passes through a planet’s gaseous envelope, it is possible to identify the molecules present and better understand their composition.

“To date, we know of only a few systems that are close enough to meet the other criteria required for this type of research, called transmission spectroscopy, using existing capabilities,” says co-author. Michael McElwainastrophysicist at NASA’s Goddard Space Flight Center, “but to better understand the diversity of atmospheres around temperate planets like Earth, we need more examples like Gliese 12 b.”

References: M. Kuzuhara and others — “Gliese 12 b: a temperate Earth-sized planet with a size of 12 pc, ideal for atmospheric transmission spectroscopy.” Magazine Astrophysical Journal Letters (ApJL), 2024 | DOI: 10.3847/2041-8213/ad3642. /// S. Dholakia and others — “Gliese 12 b, a temperate planet the size of Earth with a diameter of 12 parsecs, discovered by TESS and CHEOPS”. Magazine Monthly Notices of the Royal Astronomical Society (MNRAS), 2024 | DOI: 10.1093/mnras/stae1152.