An international team of astronomers has reported the discovery of a new super-Neptunian exoplanet orbiting a solar-type star. The newly discovered alien world, called TOI-5005 b, is approximately six times larger than Earth and has a mass 30 times greater. The discovery was detailed in an article published on the preprocessing server on September 26. arXiv.

NASA’s Transiting Exoplanets Search Satellite (TESS) surveys approximately 200,000 of the brightest stars near the Sun in search of transiting exoplanets. More than 7,200 candidate exoplanets (TESS Objects of Interest, or TOIs) have been detected so far, of which 557 have been confirmed.

Recently, a team of astronomers led by Amadeo Castro-González from the Center for Astrobiology in Madrid, Spain, confirmed another TOI observed by TESS. They found a transition signal in the light curve of TOI-5005, a moderately bright solar-type star of spectral type G2V, located about 685 light-years away. The planetary nature of this signal was confirmed by subsequent observations using ground-based instruments.

“In this study, we used TESS, HARPS, PEST, and TRAPPIST-South data to confirm the planetary nature of TOI-5005 b and characterize its orbital and physical properties,” the researchers wrote in the paper.

The newly discovered planet has a radius of 6.25 Earth radii and a mass of 32.7 Earth masses, and its density is 0.74 g/cm3.³. It orbits its host at a distance of approximately 0.066 AU every 6.31 days. The planet’s equilibrium temperature is believed to be 1040 K.

Examining the internal structure of TOI-5005 b, astronomers calculated that the mass fraction of its core and the mass fraction of metal in the shell are approximately 0.74 and 0.08, respectively. Overall, the total metal mass ratio of this exoplanet was calculated to be 0.76, slightly lower than that of Uranus and Neptune. These results indicate that TOI-5005 b was formed by nuclear accumulation.

Based on the data obtained, the authors of the article classified TOI-5005 b as a super-Neptune near the ridge of the “Neptunian savannah”. The region called the Neptunian desert and savanna is noted for the absence of Neptunian exoplanets in the shortest period orbits and their moderate occurrence at large orbital distances. They are distinguished by Neptune’s recently discovered extreme density (ridge) in its orbital period of 3-5 days.

TOI-5005 b is a new member of the generally rare low-density Neptunian population in the Neptunian Savannah, unlike dorsal planets that typically exhibit higher densities above 1.0 g/cm3, the researchers noted.³.

In their concluding remarks, the scientists added that TOI-5005’s brightness makes the newly discovered planetary system an important target for observations of its atmosphere and orbital architecture.