Extragalactic planet
An extragalactic planet, also known as an extragalactic exoplanet, is a planet that is outside the Milky Way. Due to the huge distance to those worlds, they are very hard to detect.
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HIP 13044 b
A planet with a mass of at least 1.25 times that of Jupiter had been potentially discovered by the European Southern Observatory (ESO) orbiting a star of extragalactic origin, even though the star now finds itself within our own galaxy. HIP 13044 is a star about 2000 light years away in the southern constellation of Fornax.;[1] part of the Helmi stream of stars, a leftover remnant of a small galaxy that collided with and was absorbed by the Milky Way over 6 billion years ago.[2] The Jupiter-like planet was particularly unusual, as it was orbiting a star nearing the end of its life and seemed about to be engulfed by it, giving tantalizing clues about the fate of our own planetary system in the distant future.
Subsequent analysis of the data revealed problems with the potential planetary detection: for example an erroneous barycentric correction had been applied (the same error had also led to claims of planets around HIP 11952 that were subsequently refuted). After applying the corrections, there is no evidence for a planet orbiting the star.[3]
A microlensing event in the Twin Quasar gravitational lensing system was observed in 1996, by R. E. Schild, in the "A" lobe of the lensed quasar. It is predicted that a 3-Earth-mass planet in the lensing galaxy, YGKOW G1, caused the event. This was the first extragalactic planet candidate announced. This, however, is not a repeatable observation, as it was a one-time chance alignment. This predicted planet lies 4 billion light years away.[4][5]
Andromeda Galaxy planets
A team of scientists has used gravitational microlensing to come up with a tentative detection of an extragalactic exoplanet in Andromeda, our nearest large galactic neighbor. The lensing pattern fits a star with a smaller companion weighing just 6 or 7 times the mass of Jupiter. This suspected planet is the first announced in the Andromeda Galaxy.[6][7]
See also
References
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- ↑ New Scientist (issue 2037), Do alien worlds throng faraway galaxy? Govert Schilling 06 July 1996
- ↑ Extrasolar Visions, "The Q0957+561 Planet" (accessed 1 September 2009)
- ↑ Thaindian News, First extragalactic exoplanet may have been found by gravitational microlensing, 11 June 2009
- ↑ New Scientist, First extragalactic exoplanet may have been found, 10 June 2009
