OGLE-2005-BLG-390Lb

Exoplanet

OGLE-2005-BLG-390Lb

OGLE-2005-BLG-390Lb. Discovered: 2005. Planet type: Neptune-like 🌎 

OGLE-2005-BLG-390L b is a Neptune-like exoplanet that orbits an unknown-type star. Its mass is 5.5 Earths, it takes 9 years to complete one orbit of its star, and is 2.6 AU from its star. Its discovery was announced in 2005.

The planet is estimated to be about five times Earth's mass (5.5+5.5−2.7 M⊕). Some astronomers have speculated that it may have a rocky core like Earth, with a thin atmosphere. Its distance from the star and the star's relatively low temperature means that the planet's likely surface temperature is around 50 K (−220 °C; −370 °F), making it one of the coldest known. If it is a rocky world, this temperature would make it likely that the surface would be made of frozen volatiles, substances which would be liquids or gases on Earth: water, ammonia, methane, and nitrogen would all be frozen solid. If it is not a rocky planet, it would more closely resemble an icy gas planet like Uranus, although much smaller.

Detection Method: Microlensing

This method derives from one of the insights of Einstein's theory of general relativity: gravity bends space. We normally think of light as traveling in a straight line, but light rays become bent when passing through space that is warped by the presence of a massive object such as a star. This effect has been proven by observations of the Sun's gravitational effect on starlight.

When a planet happens to pass in front of a star along our line of sight, the planet's gravity will behave like a lens. This focuses the light rays and causes a temporary sharp increase in brightness and change of the apparent position of the star. Astronomers can use the gravitational microlensing effect to find objects that emit no light or are otherwise undetectable.

Observed By

OGLE

In popular culture

The planet has been given the unofficial name of Hoth by NASA due to its resemblance to the planet with the same name from the Star Wars franchise. A similar exoplanet, OGLE-2016-BLG-1195Lb, has also been compared to Hoth.

OGLE-2005-BLG-390L's location in the night sky

OGLE-2005-BLG-390L's location in the night sky

Details from NASA