New rare 'hot sub-Neptune' exoplanet discovered

Tomasz Nowakowski is a member of the physics.org community.

A new alien world has been detected using NASA's transiting exoplanet survey satellite. The exoplanet, named TOI-2196 b, is a hot sub-Neptune. A paper detailing the discovery was published on arXiv.org.

The aim of the survey is to find transiting exoplanets, which are planets outside the solar system. Over 5,800 candidate exoplanets have been identified and 233 have been confirmed.

Another TOI has recently been confirmed by a group of astronomer led by Carina M. Persson of the Chalmers University of Technology in Sweden. There is a transit signal in the light curve of a G type star. The planetary nature of the signal was confirmed by the follow-up RV measurement on the 3.6 m telescope.

The planet TOI-2196 b is a hot and volatile one. It's 50% more massive than Neptune and has a high bulk density.

The observations show that TOI-2196 b is more massive than the planet. A bulk density of 3.31 g/ cm 3 is given.

The astronomer said that TOI-2196 b is a hot sub-Neptune and represents the hot Neptune desert.

There is a small number of Neptunes in the hot Neptune desert. The authors of the paper said that highly irradiated planets are either small or rocky and can be gas giants.

The results show that the planet's character has not changed despite the mass loss of TOI-2196 b. According to the researchers, it formed as a small volatile-rich planet and has been there ever since.

The star TOI-2196 is the size and mass of the sun. Its age is estimated to be 4.5 billion years and it has an effective temperature of 5000 K. The astronomer thinks that the star may be in the wrong place. A brown dwarf, or a very low-mass stellar companion, can't be completely excluded from this outer body. There is a need for long-term RV monitoring to verify this hypothesis.

More information: Carina M. Persson et al, TOI-2196 b: Rare planet in the hot Neptune desert transiting a G-type star. arXiv:2208.05797v2 [astro-ph.EP], arxiv.org/abs/2208.05797

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