page_title: Active asteroid
hierarchical_section_title: Active asteroid
caption_attribution_description: English: 5 minute exposure of main belt asteroid 596 Scheila with a 24" telescope. You can clearly see signs of Scheila acting like a main-belt comet and displaying a cometary tail. This image was taken at 2010-12-12 12:00 UT.
context_page_description: Active asteroids are small Solar System bodies that have asteroid-like orbits but show comet-like visual characteristics. That is, they show comae, tails, or other visual evidence of mass-loss, but their orbit remains within Jupiter's orbit. These bodies were originally designated main-belt comets in 2006 by astronomers David Jewitt and Henry Hsieh, but this name implies they are necessarily icy in composition like a comet and that they only exist within the main-belt, whereas the growing population of active asteroids shows that this is not always the case.
  The first active asteroid discovered is 7968 Elst–Pizarro. It was discovered in 1979 but then was found to have a tail by Eric Elst and Guido Pizarro in 1996 and given the cometary designation 133P/Elst-Pizarro.
context_section_description: Active asteroids are small Solar System bodies that have asteroid-like orbits but show comet-like visual characteristics. That is, they show comae, tails, or other visual evidence of mass-loss (like a comet), but their orbit remains within Jupiter's orbit (like an asteroid). These bodies were originally designated main-belt comets (MBCs) in 2006 by astronomers David Jewitt and Henry Hsieh, but this name implies they are necessarily icy in composition like a comet and that they only exist within the main-belt, whereas the growing population of active asteroids shows that this is not always the case.
  The first active asteroid discovered is 7968 Elst–Pizarro. It was discovered (as an asteroid) in 1979 but then was found to have a tail by Eric Elst and Guido Pizarro in 1996 and given the cometary designation 133P/Elst-Pizarro.
caption: Asteroid (596) Scheila displaying a comet-like appearance on December 12, 2010.
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