Kepler-13 Ab es un planeta extrasolar descubierto en 2011 por la misión Kepler de la NASA en torno a una estrella en un sistema estelar múltiple. Se trata de un gigante gaseoso caliente que orbita a su estrella madre en menos de dos días.^[2]​

Kepler 13 Ab
Descubrimiento
Descubridor	Fortney et al.[1]​
Fecha	2011[1]​
Método de detección	Tránsito[1]​
Lugar	Kepler (misión)
Categoría	planeta extrasolar
Estado	Publicado[1]​
Estrella madre
Orbita a	Kepler-13A
Constelación	Lyra
Ascensión recta (α)	286,97141527971 grados sexagesimales
Declinación (δ)	46,868314223157 grados sexagesimales
Tipo espectral	A
Magnitud aparente	10
Elementos orbitales
Inclinación	86,04 grados sexagesimales
Argumento del periastro	128 grados sexagesimales
Semieje mayor	0,038[1]​ UA
Excentricidad	0.00064
Elementos orbitales derivados
Período orbital sideral	1,7637[1]​ días
Características físicas
Masa	5-8[1]​ MJ
Radio	1,4[1]​ RJ
Gravedad	m/s2
[editar datos en Wikidata]

Nighttime Titanium Oxide Snow Leaves Dayside Cloud-Free and Cooler

Travelers to the nightside of exoplanet Kepler-13Ab should pack an umbrella because they will be pelted with precipitation. But it's not the kind of watery precipitation that falls on Earth. On this alien world, the precipitation is in the form of sunscreen.

Ironically, the sunscreen (titanium oxide) is not needed on this side of the planet because it never receives any sunlight. But bottling up some sunlight protection is a good idea if travelers plan on visiting the sizzling hot, permanent dayside, which always faces its star. Visitors won't find any desperately needed sunscreen on this part of the planet.

Astronomers didn't detect the titanium oxide directly. They used Hubble to find that the atmospheric temperature grows increasingly colder with altitude on Kepler-13Ab, which was contrary to what they had expected. If titanium oxide were in the daytime atmosphere, it would absorb light and heat the upper atmosphere. Instead, high winds carry the titanium oxide around to the permanently dark side of the planet where it condenses to form clouds and precipitation. The planet's crushing gravity pulls all the titanium oxide so far down it can't be recycled back into the upper atmosphere on the daytime side.

The Hubble observations represent the first time astronomers have detected this precipitation process, called a "cold trap," on an exoplanet.

Kepler-13Ab is one of the hottest known planets, with a dayside temperature of nearly 5,000 degrees Fahrenheit (2 760 °Celsius). The Kepler-13 system resides 1,730 light-years from Earth.