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Path: utzoo!watmath!clyde!burl!ulysses!mhuxl!ihnp4!zehntel!hplabs!hao!noao!kpnoa!parks
From: parks@kpnoa.UUCP
Newsgroups: net.astro.expert
Subject: Stability of the 'Nemesis' system
Message-ID: <339@kpnoa.UUCP>
Date: Thu, 24-May-84 12:57:11 EDT
Article-I.D.: kpnoa.339
Posted: Thu May 24 12:57:11 1984
Date-Received: Thu, 31-May-84 20:00:51 EDT
Organization: Natl. Optical Astronomy Observatories   Tucson AZ  USA
Lines: 21

I have in my hands a preprint of a paper by Piet Hut (from Princeton)
concerning the possibility of a companion star which orbits ours at
about a light year out.  I'm not sure, but I believe this is being
submitted to Letters to the Astrophysical Journal, so it may appear in
print in about six months.  The current title for the article is 
"How stable is an astronomical clock which can trigger mass extinctions 
on earth?".  It seems he will also be publishing a more detailed analysis
of his calculations (although I don't know where).

I don't want to reveal too much of his paper (get your own pre-print),
but he has done extensive computer simulations on a VAX 11/780, including: 
over 10^7 stellar encounters, the galactic tidal field, and various
orbit orientations to the galactic plane.

After studying these effects, he concludes that such a system IS
possible, although it should come apart in time.  A related factor to
its instability is that the period is not precisely regular, but may
vary as much as 20%.

                                     Jay Parks
          (decvax!hao!ihnp4!seismo)!noao!parks     :uucp