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View Full Version : Why are most star systems that we know of Binary Systems?



Beauregard88
2012-Mar-04, 09:44 PM
Hello all, love the forums, been a lurker for a while now. So my question is, why are most star systems that we know of, binary instead of single? This has always interested me, seeing as how our own solar system has only one star, the sun. When stars go through the creation process, what makes the majority of them become binary systems? Thanks guys.

dtilque
2012-Mar-05, 08:57 AM
Actually, it turns out that most stars are not in binary or multiple star systems. Most stars (about 70%) are dim spectral class M stars and they seem to be mostly singles. However, most bright stars are binaries and since these are more prominent, it gave everyone the wrong impression about the fraction of stars that are binary.

Now why bright stars are binaries is a question I'll leave to those more expert on the formation of stars.

astromark
2012-Mar-05, 09:19 AM
So the answer you seek is that 'most' are not binaries... but there is a lot that are.. So to that I offer..

The nebular debris that coleuses into a planetary disk might often contain such mater as to be able to form in that disk more than one stellar object.. Binary or multi star systems abound. Most it would seem do have planets..

Its just a mater of mater available..

Romanus
2012-Mar-05, 11:39 AM
Simulations suggest that many--if not the vast majority of--binary systems form as a by-product of a rapidly spinning protostar, as they often split as rotation increases. It's a way for one star to "lose" angular momentum while, of course, conserving the overall momentum of the system.

StupendousMan
2012-Mar-05, 01:15 PM
Actually, it turns out that most stars are not in binary or multiple star systems. Most stars (about 70%) are dim spectral class M stars and they seem to be mostly singles. However, most bright stars are binaries and since these are more prominent, it gave everyone the wrong impression about the fraction of stars that are binary.

Now why bright stars are binaries is a question I'll leave to those more expert on the formation of stars.

The evidence does suggest that low-mass stars occur in binaries less frequently than high-mass stars (see the introduction of http://arxiv.org/abs/1110.4016 for a review), but it's not completely clear yet what fraction of M stars occur in binaries. A recent spectroscopic survey suggests a relatively small fraction at small separation (http://arxiv.org/abs/1110.4016), but surveys of star-forming regions suggest higher fractions at large separations ( http://arxiv.org/abs/1201.1311).

This is a good area for more observations!