Astronomers have confirmed the presence of a new exoplanet discovered in observations from Transiting Exoplanet Survey Satellite (TESS). The research team, led by Yilen Gómez Maqueo Chew of the National Autonomous University of Mexico, detected a transit signal in the light curve of the star TOI-1080, an inactive M4V-type red dwarf. 

Subsequent follow-up observations with ground-based telescopes confirmed that the signal was indeed caused by a planet passing in front of the star. The newly identified world is slightly larger than Earth and completes an orbit around its host star in less than four days, with details of the discovery outlined in a study published on the arXiv preprint server.

TESS is currently surveying roughly 200,000 bright stars near the Sun in search of transiting exoplanets. So far, the mission has cataloged nearly 7,900 candidates known as TESS Objects of Interest, with 759 of them already confirmed as planets.

Temperate super-Earth around an M-dwarf star

The team reports that the observations validate the planetary nature of the object and identify it as a temperate rocky planet circling an M4V-type star. The study suggests that TOI-1080 b is likely a rocky super-Earth. Measurements indicate the planet has a radius about 1.2 times that of Earth, while its mass is estimated to be below 10.7 Earth masses and most likely close to 1.75 Earth masses, Phys.org writes.

The planet completes one orbit around its host star in roughly 3.97 days and lies extremely close to it at a distance of about 0.027 astronomical units. Based on these parameters, scientists estimate the planet’s equilibrium temperature to be around 368 K, placing it in a relatively warm but still temperate range for rocky exoplanets.

The observed characteristics suggest that TOI-1080 b is a temperate super-Earth with a likely rocky composition. Because the planet orbits inside the habitable zone of its host star, scientists suggest it could possess an atmosphere dominated by carbon dioxide or possibly a dense oxygen-rich layer. However, additional atmospheric characterization studies will be needed to determine whether such an atmosphere is actually present.

Red dwarf hosting TOI-1080 b may contain more hidden planets

Researchers also analyzed the properties of the host star TOI-1080. The red dwarf is about five times smaller than the Sun and has a mass of roughly 0.16 solar masses. Its effective surface temperature is estimated at around 3,065 K, while its metallicity is measured at −0.25 dex. Based on stellar models, astronomers believe the star is at least 5 to 7 billion years old.

Since stars in the M dwarf stars category frequently host compact multi-planet systems, the team also examined whether additional planets might be orbiting TOI-1080. Their analysis aimed to determine if other yet-undetected worlds could be present in the system alongside TOI-1080 b.

According to the study, the available observations place strong limits on the presence of other nearby planets in the system. Based on the available TESS data, the researchers determined that no additional transiting planets larger than 0.9 Earth radii are present with orbital periods between 0.5 and 7.7 days. For longer orbital periods, up to about 19 days, the analysis indicates that planets larger than roughly 1.4 Earth radii can also be ruled out in the system.