NASA discovers a “hot Neptune” in which a year lasts 21 hours

An international team of NASA discovered an exoplanet of a very rare type: it is called TOI-3261 b and it is a “hot Neptune”with an ultrashort period of revolution around its star. The team coordinated by Emma Nabile identified it thanks to the Tess (Transiting Exoplanet Survey Satellite) space telescope, then studied it in depth with ground-based telescopes located in Australia, Chile and South Africa.

It is located 979 light years from Earth Within the hot desert of Neptune, it is similar in size and composition to that planet, although it orbits extremely close to its stars. A year on TOI-3261 lasts only 21 hours, its relatively short orbit adds it to the club of the other three hot Neptunes on record: LTT-9779b, TOI-849b and TOI-332b. Its evolutionary history remains a mystery. How do they maintain their atmosphere? Here are the researchers’ hypotheses.

The origin

The planetary system is estimated to be about 6.5 billion years old, but its origin as an exoplanet is difficult to reconstruct. Researchers theorize that the influence of the sun’s gravitational pull and solar winds must have swept away the gaseous layers, but we know this did not happen.

TOI-326 b retains its atmosphere intact, although twice as dense as that of Neptune. For this reason, Scientists speculate that the exoplanet was born much larger than it appears, similar to the size of Jupiter, and that it lost mass over time. Another theory is that it formed farther from the star than it is now, enough to limit the effects of photoevaporation; process by which radiation emitted by the star strips away the gas surrounding the planet and tidal forces.

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The atmosphere of Mars was not lost to space but was partly absorbed by the planet’s clay and its elements could still be there.

An interesting atmosphere

The characteristics of the atmosphere of TOI-326 b will be investigated soon and could help unravel the history of its formation and that of similar exoplanets. Although only the heavy elements remain, researchers believe NASA’s James Webb telescope will be useful in identifying atomic signatures in the planet’s atmosphere, which would help understand the past of not only TOI-326 b, but also other hot Neptunes. similar, such as LTT-9779 b, the first ultra-short period exoplanet discovered.

Article originally published in WIRED Italy. Adapted by Alondra Flores.