(MENAFN) An international group of astronomers, led by a Turkish researcher, has identified four previously unknown exoplanets, including one situated on the inner edge of its star’s habitable zone that could possess an atmosphere, located roughly 90 light-years from Earth.

The discoveries stem from the doctoral research of Selcuk Yalcinkaya, a PhD candidate whose thesis focused on “the discovery and validation of four super-Earth to Neptune-sized planets around M dwarfs.” The findings were published in the October 2025 issue of Astronomy & Astrophysics, a leading journal in the field.

Yalcinkaya, who serves as a research assistant in astronomy and space sciences at Ankara University, received funding from the Turkish Scientific and Technological Research Institution (Tubitak) through its “International Research Fellowship Program for PhD Students.” Part of his work was carried out at the University of Liege in Belgium.

The research team, which included a Nobel laureate among its members, employed widely-used techniques such as the “transit and radial velocity methods” to detect the planets.

The newly discovered exoplanets are distributed across three star systems: two orbit the small, cool star TOI-5799, while one each circles TOI-1743 and TOI-6223. Observational data came from the AU Kreiken Observatory and the Turkish National Observatory.

One planet in the TOI-5799 system, named TOI-5799c, lies within the star’s habitable zone.

According to Yalcinkaya, the planets were initially flagged as candidates through observations by the TESS Space Telescope, which monitors transit signals over a 30-day period. Ground-based observatories are then used to identify which star in the region is responsible for the signal.

“One of the planets we discovered, the ‘TOI-6223b,’ is the size of Neptune but very close to its own star, which is why it’s called a hot Neptune,” Yalcinkaya explained. “While it has a radius similar to that of Neptune’s, we need to look at what gases are present in its atmosphere.”

He added, “Meanwhile, the other one, the ‘TOI-1743b,’ is a super-Earth -- it is about 70% larger than our planet and it is terrestrial. It probably can’t retain volatile gases in its atmosphere -- it is also very close to its star and therefore hot.”

The TOI-5799 system is notable for hosting two of the newly discovered exoplanets, TOI-5799b and TOI-5799c, both roughly 70% larger than Earth and likely terrestrial. While TOI-5799b orbits close to its star and is hot, TOI-5799c resides in the habitable zone, completing an orbit every 14 days.

“The exoplanet is at a distance where water could potentially exist as liquid due to its surface temperature of around 63 degrees Celsius (145.4 degrees F), but the atmosphere could change things a bit as we don’t know what kind of atmosphere it has,” Yalcinkaya said. “It could be much hotter than expected or colder -- we don’t know yet. If there’s life there, there may be some bio-signs in its atmosphere -- we can observe this in the future to see if there’s life there or not. Life may exist on many planets, but if there’s life in the ‘TOI-5799c,’ it is possible to find out.”

Ozgur Basturk, a professor of astronomy and space sciences at Ankara University and Yalcinkaya’s thesis supervisor, noted that the team’s observations relied on nearly 20 telescopes located worldwide, spanning Chile, Türkiye, Mexico, and the Canary Islands.

“The ‘TOI-5799c’ is a planet in the habitable zone but this does not necessarily mean that life exists there,” Basturk cautioned. “We need to find out if it has an atmosphere -- this is what Yalcinkaya wishes to research next.”

He added that the James Webb Space Telescope could help monitor transits of the exoplanet to identify potential signs of life in its atmosphere. “There are no terrestrial planets with atmospheres, but this one, the ‘TOI-5799c,’ is among the few candidates,” Basturk concluded.

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