NGC 2685

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Helix Galaxy
NGC 2685.jpg
Image by Ken Crawford
Observation data
Constellation Ursa Major
Other designations
NGC 2685, Arp 336
See also: Galaxy, List of galaxies

NGC 2685 (also known as the Helix Galaxy) is a lenticular and polar-ring galaxy in the constellation Ursa Major. It is about 50,000 light-years across and about 42 million light-years away from Earth. It is receding from Earth at 883 kilometers per second. It is an object of great scientific interest, because polar-ring galaxies are very rare galaxies. They are thought to form when two galaxies gravitationally interact with each other. "The bizarre configuration could be caused by the chance capture of material from another galaxy by a disk galaxy, with the captured debris strung out in a rotating ring. Still, observed properties of NGC 2685 suggest that the rotating ring structure is remarkably old and stable."[1]

Allan Sandage referred to NGC 2685 as "perhaps the most peculiar galaxy in the Shapley-Ames Catalog".[2]



  1. ^ *"Polar Ring Galaxy NGC 2685". Retrieved 2014-03-14. 
  2. ^ Sidney Van den Bergh (16 April 1998). Galaxy Morphology and Classification. Cambridge University Press. p. 3. ISBN 978-0-521-62335-3.