Extragalactic planet

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Artist's impression of HIP 13044 b, the first discovered planet of extragalactic origin. This planet was detected using the MPG/ESO 2.2-metre telescope at ESO's La Silla Observatory.[1]

An extragalactic planet, also known as an extragalactic exoplanet, is a planet that is outside the Milky Way.[2]

Twin Quasar-related planet[edit]

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 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.[3][4]

Andromeda galaxy planets[edit]

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 neighbour. 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.[5][6]

HIP 13044[edit]

HIP 13044 is a star about 2000 light years away within the Milky Way galaxy which was announced to have an exoplanet. The star is 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.[7] Further investigation revealed that the planet does not exist and that the detection was due to poor data sampling and incorrect correction for the Earth's orbital motion.[8]

See also[edit]


  1. ^ "Planet from another galaxy discovered". ESO Press Release (in English). 18 November 2010. Retrieved 17 November 2011. 
  2. ^ Extrasolar Visions, "Extragalactic Worlds" (accessed 1 September 2009)
  3. ^ New Scientist (issue 2037), Do alien worlds throng faraway galaxy? Govert Schilling 06 July 1996
  4. ^ Extrasolar Visions, "The Q0957+561 Planet" (accessed 1 September 2009)
  5. ^ Thaindian News, First extragalactic exoplanet may have been found by gravitational microlensing, 11 June 2009
  6. ^ New Scientist, First extragalactic exoplanet may have been found, 10 June 2009
  7. ^ Discover Magazine; Bad Astronomy Blog, "Exoplanet found… from another galaxy!!", 18 November 2010
  8. ^ Jones, M. I.; Jenkins, J. S. (2014). "No evidence of the planet orbiting the extremely metal-poor extragalactic star HIP 13044". Astronomy & Astrophysics 562: id.A129. arXiv:1401.0517. Bibcode:2014A&A...562A.129J. doi:10.1051/0004-6361/201322132.