‘Iceball’ Planet discovered through Microlensing technique

An icy world, much colder than Pluto in our solar system, was found in orbit around a tiny star 13,000 light years away. The planet has been designated as OGLE-2016-BLG-1195Lb, and is the smallest known object to be discovered through a technique known as microlensing. When a star passes in front of another star, it causes the background star to appear brighter by focusing the light via its gravity. If a planet passes in front of the foreground star, there is an additional blip in brightness, that lasts for only a few hours.

The discovery could have implications in our understanding of the distribution of planets in the galaxy. The finding adds evidence that the number of planets in orbit around stars reduce closer to the center of a galaxy. The newly discovered planet is also in the outer edge of the galaxy, much like our own solar system. The planet has the mass of the Earth, and has been discovered at a similar distance from its host star as the Earth is from the Sun. Geoff Bryden, astronomer at JPL said “Although we only have a handful of planetary systems with well-determined distances that are this far outside our solar system, the lack of Spitzer detections in the bulge suggests that planets may be less common toward the center of our galaxy than in the disk.”

The star, known as OGLE-2016-BLG-1195L is on the border line between a planet and a star, an object known as a brown dwarf. The star is only 7.8 percent the mass of our sun. Alternatively, the star could be an ultracool dwarf, similar to Trappist-1. There are seven Earth sized planets in orbit around Trappist-1, but the planets are all much closer to the star than OGLE-2016-BLG-1195Lb is to its host star, allowing for liquid water to exist on the surface, and potentially hosting conditions suitable for life.

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