A hot Neptune is a type of giant planet with a mass similar to that of Uranus or Neptune in an orbit close to its star, normally less than 1 AU. The first hot Neptune to be discovered with certainty was Gliese 436 b in 2007, an exoplanet about 33 light years away. Recent observations have revealed a larger potential population of hot Neptunes in the Milky Way than previously thought.
Because of their close proximity to their parent star, hot Neptunes have a much greater rate and chance of transiting their star as seen from a farther outlying point, than planets of the same mass in larger orbits. This increases the chances of discovering them by transit-based observation methods.
Transiting hot Neptunes include Gliese 436 b and HAT-P-11b, which was recently observed by the Kepler mission. Gliese 436 b (also known as GJ 436b) was the first hot Neptune to be discovered with certainty in 2007. The exoplanet Mu Arae c (or HD 160691 c) discovered in 2004 might also be a hot Neptune, but it has not been determined definitively.
- G. Wuchterl. "Hot Neptunes: A Key To Giant Planet Formation" (PDF). cosis.net. Retrieved 3 August 2015.
- Oligarchic formation of hot Neptunes
- Adrián Brunini and Rodolfo G. Cionco (September 2005). "The origin and nature of Neptune-like planets orbiting close to solar type stars". Icarus. Elsevier. 177: 264–68. arXiv:astro-ph/0511051. Bibcode:2005Icar..177..264B. doi:10.1016/j.icarus.2005.02.015. Retrieved 3 August 2015.
- Gillon, et. al. (September 2007). "Detection of transits of the nearby hot Neptune GJ 436 b". 472 (2): L13–L16. doi:10.1051/0004-6361:20077799.
- Paul Gilster (2007-05-16). "Transiting 'Hot Neptune' Found". Centauri Dreams. A discussion of the "Detection of transits of the nearby hot Neptune GJ 436 b" paper.