OGLE-2005-BLG-390Lb, sometimes referred to by NASA as Hoth (from the movie Star Wars) is a super-Earth extrasolar planet orbiting the red dwarf star OGLE-2005-BLG-390L, located around 21,500 light years away from Earth in the constellation of Scorpius. The planet and its star are near the center of the Milky Way Galaxy. The planet is likely not habitable. At a distance of 21,500 light years, it is one of the most distant extrasolar planets ever found.
Characteristics[]
Mass, radius, and temperature[]
The planet has an estimated mass of around 5.5 Earth masses. Some astronomers believe that the planet may have a rocky core like the Earth, and possess a thin atmosphere. The planets distance from its host star and the star's relatively low temperature means that the planet likely has a surface temperature of 50 K (−220 °C; −370 °F), which makes it the coldest extrasolar planet known so far. Assuming it is a terrestrial planet it likely has a surface made of frozen volatiles.
The planet is notable for its very large distance from its star for such a relatively small exoplanet. OGLE-2005-BLG-390Lb shows a combination of size and orbit that would not make it out of place in the Solar System.
At the time of its discovery, the planet was one of the most Earth-like planets found, and was the least massive planet found around a main-sequence star, the previous record holder being Gliese 876 d at 7.5 Earth masses. Since 2013, many Earth-sized or smaller planets around main-sequence stars have been found by the Kepler spacecraft and others.
Host star[]
OGLE-2005-BLG-390L is a cool red dwarf star located in the constellation of Scorpius, at 21,500 light years from Earth. It has a 95% chance of being a cool red dwarf, a 4% chance of being a white dwarf, and a <1% chance of being a neutron star or black hole. It has a mass of 0.22 Solar masses, but an unknown radius. If it is a red dwarf it likely has a radius of around 0.17 Solar radii. The estimated age of the star is 9.587 billion years.
Orbit[]
OGLE-2005-BLG-390Lb orbits its host star around every 3,500 days (or around 10 Earth years), at an average distance of 2.0-4.1 AU. This orbit would fall between the orbits of Mars and Jupiter if it was in the Solar System. Note that the range of distances is the range of error in measurement and calculation as it doesn't represent the planet's orbital eccentricity, since this isn't known.
Discovery[]
OGLE-2005-BLG-390Lb's signature was first detected on August 10, 2005, by observations at the Danish 1.54-m telescope at ESO La Silla Observatory in Chile.
References[]
The planet has been given the unofficial name of "Hoth", from the Star Wars franchise, due to the planets resemblance to the "Hoth" planet featured in Star Wars. A similar exoplanet (OGLE-2016-BLG-1195Lb) has also been compared to Hoth.