X-rated galaxies
Posted: Tuesday, October 30, 2007 6:09 PM by Alan Boyle
NASA / ESA / STScI / AURA |
A stellar tendril from the galaxy NGC 3808, at right, twists around the smaller
galaxy NGC3808A in this image from the Hubble Space Telescope.
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If galaxies were people, the latest image from the Hubble Space Telescope might be rated for mature audiences only. A stream of stars twists seductively from one galaxy to encircle its smaller companion, illustrating how gravitational attraction can set the stellar sparks flying.
The galaxy pair, known as Arp 87, lies 300 million light-years away in the constellation Leo and was cataloged in the 1960s by astronomer Halton Arp in his Atlas of Peculiar Galaxies. NGC 3808 is the nearly face-on spiral galaxy seen at right, and the smaller edge-on galaxy at left is NGC 3808A.
Gravitational interaction between such galaxies spark some of the highest star formation rates in the universe - and in this case, a corkscrew of stars, gas and dust is being pulled from the larger galaxy to form a corkscrewing "polar ring" that encircles NGC 3808A in a direction perpendicular to the galaxy's plane. Kinky!
The dancing galaxies were observed in February by Hubble's Wide Field Planetary Camera 2. The Hubble Heritage Team combined visible-light and infrared views to produce today's masterpiece. For a cool zoom-in video and additional goodies, check in with Hubble's European Web site.
Hubble has looked at several "peculiar galaxies" before, including Arp 297 and Arp 220, and there's a whole gallery of interacting galaxies at the University of Alabama. If you're into this sort of thing, you'll definitely want to revisit Hubble's imagery of "the Mice" and a grazing galactic encounter between NGC 2207 and IC 2163. NASA's Spitzer Space Telescope has a color-coded view of that same encounter that's suitable for a Halloween mask.
Visit our space gallery for further twists on extraterrestrial imagery.
