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takyon [soylentnews.org] writes:

The 'Forbidden' Planet has been found in the 'Neptunian Desert' [warwick.ac.uk]

NGTS-4b, also nick-named 'The Forbidden Planet' by researchers, is a planet smaller than Neptune but three times the size of Earth and is 920 light-years away from Earth.

It has a mass of 20 Earth masses, and a radius 20% smaller than Neptune, and is 1000 degrees Celsius. It orbits around the star in only 1.3 days – the equivalent of Earth's orbit around the sun of one year.

It is the first exoplanet of its kind to have been found in the Neptunian Desert.

The Neptunian Desert is the region close to stars where no Neptune-sized planets are found. This area receives strong irradiation from the star, meaning the planets do not retain their gaseous atmosphere as they evaporate leaving just a rocky core. However NGTS-4b still has its atmosphere of gas.

When looking for new planets astronomers look for a dip in the light of a star – this the planet orbiting it and blocking the light. Usually only dips of 1% and more are picked up by ground-based searches, but the NGTS telescopes can pick up a dip of just 0.2%

Researchers believe the planet may have moved into the Neptunian Desert recently, in the last one million years, or it was very big and the atmosphere is still evaporating.

NGTS-4b: A sub-Neptune transiting in the desert [oup.com] (open, DOI: 10.1093/mnras/stz1084) (DX [doi.org])

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