Fomalhaut C Has a Huge Cometary Debris Ring And, Potentially, Exoplanets 32
astroengine writes "Astronomers scoping-out the vicinity of the famous star Fomalhaut have discovered that its mysterious stellar sister is also sporting a rather attractive ring of comets. Located 25 light-years away in the constellation Piscis Austrinus, Fomalhaut A is one of the brightest stars in Southern Hemisphere skies. The bright blue giant is notable in that it hosts a gigantic ring of cometary debris and dust. Fomalhaut C is a red dwarf star and was only confirmed to be gravitationally bound Fomalhaut A and Fomalhaut B in October. Fomalhaut is therefore a triple, or trinary, star system. The small red dwarf star may be the proverbial runt of the Fomalhaut stellar litter, but it appears to share some common ground with its larger sibling. 'It's very rare to find two comet belts in one system, and with the two stars 2.5 light years apart this is one of the most widely separated star systems we know of,' said astronomer Grant Kennedy, of the University of Cambridge and lead researcher of this work. 'It made us wonder why both Fomalhaut A and C have comet belts, and whether the belts are related in some way.' One of the reasons why Fomalhaut A's cometary disk is so bright is down to the presence of its exoplanet, stirring up comet collisions. Fomalhaut C may be experiencing the same mechanism."
link to the triple-star discovery (Score:5, Interesting)
As the summary notes, it was only recently discovered that this system has three gravitationally bound stars, making it the widest such group currently known. Paper from a few months ago [arxiv.org] on the arXiv, and a news write-up [phys.org] of that.
Re:link to the triple-star discovery (Score:2, Interesting)
The cool part: ""Fomalhaut C looks quite far apart from the big, bright star that is Fomalhaut A when you look up at the sky from Earth," added Mamajek. There are roughly 5.5 degrees between the two stars, which is as if they were separated by roughly 11 full moons for an observer on Earth. Mamajek explained that they look this far apart, in part, because Fomalhaut is relatively close to Earth as stars go – approximately 25 light years."