The Neptunian Desert or sub-Jovian desert is broadly defined as the region close to a star (

period Period may refer to: Common uses * Era, a length or span of time * Full stop (or period), a punctuation mark Arts, entertainment, and media * Period (music), a concept in musical composition * Periodic sentence (or rhetorical period), a concept ...

< 2–4 days) where no

Neptune Neptune is the eighth planet from the Sun and the farthest known planet in the Solar System. It is the fourth-largest planet in the Solar System by diameter, the third-most-massive planet, and the densest giant planet. It is 17 times ...

-sized (> 0.1 )

exoplanets An exoplanet or extrasolar planet is a planet outside the Solar System. The first possible evidence of an exoplanet was noted in 1917 but was not recognized as such. The first confirmation of detection occurred in 1992. A different planet, init ...

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. Neptune-sized planets should be easier to find in short-period orbits, and many sufficiently massive planets have been discovered with longer orbits from surveys such as

CoRoT CoRoT (French: ; English: Convection, Rotation and planetary Transits) was a space telescope mission which operated from 2006 to 2013. The mission's two objectives were to search for extrasolar planets with short orbital periods, particularly th ...

and

Kepler Johannes Kepler (; ; 27 December 1571 – 15 November 1630) was a German astronomer, mathematician, astrologer, natural philosopher and writer on music. He is a key figure in the 17th-century Scientific Revolution, best known for his laws o ...

. The physical mechanisms that result in the observed Neptunian Desert are currently unknown, but have been suggested to be due to a different formation mechanism for short-period

super-Earth A super-Earth is an extrasolar planet with a mass higher than Earth's, but substantially below those of the Solar System's ice giants, Uranus and Neptune, which are 14.5 and 17 times Earth's, respectively. The term "super-Earth" refers only to ...

and Jovian exoplanets, similar to the reasons for the

brown dwarf desert The brown-dwarf desert is a theorized range of orbits around a star within which brown dwarfs are unlikely to be found as companion objects. This is usually up to 5 AU around solar mass stars. The paucity of brown dwarfs in close orbits was first ...

. The exoplanet NGTS-4b, with mass of 20 , and a radius 20% smaller than Neptune, was found to still have an atmosphere while orbiting every 1.3 days within the 'Neptunian Desert' of NGTS-4, a K-dwarf star located 922 light-years from Earth. The atmosphere may have survived due to the planet's unusually high core mass, or it might have migrated to its current close-in orbit after this epoch of maximum stellar activity.

Notes

{{Exoplanet Planetary science

See also

Notes