[net.space] 'Births of stars and their orbits'

KFL%MIT-MC@sri-unix.UUCP (06/17/83)

From:  Keith F. Lynch <KFL @ MIT-MC>


	Date: 13 Jun 83 23:00:16-PDT (Mon)
	To: physics @ Sri-Unix
	From: harpo!floyd!vax135!cornell!uw-beaver!tektronix!richk @ Ucb-Vax
	Subject: 'Births of stars and their orbits'
	
	It was stated that stars are born in groups.  Later they move off into
	seperate orbits. Thus, the suns siblings could well be on the other
	side of the galaxy from us.
	
	What is it that spreads these stars out?  Close encounters with other
	stars?  That doesn't seem too likely.  There would have to a lot of
	encounters to spread them all out.  Internal encounters seem to be too
	limited in nature to quickly disorganize the cluster.  Maybe close
	encounters with demented astronmers?  All stars hate each other?
	Anyone out there know the real reason?

  I believe it is because some of the stars are closer to the center of
the galaxy and thus are in closer and faster orbits.  Another way of
saying this is to say that they are seperated by the tidal force of the
center of the galaxy, i.e. we are within the galaxy's Roche limit.
  I think this is also why most (all?) nebulas are only a few thousand
years old.  They are pulled apart in not much more time than that.

								...Keith