Stability of the 'Nemesis' system

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3 total messages Started by parks Thu, 24 May 1984 16:57

#33

Author: parks
Date: Thu, 24 May 1984 16:57

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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

Re: Stability of the 'Nemesis' system

#35

Author: Ed Nather
Date: Sun, 27 May 1984 02:50

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[]
   >I have in my hands a preprint of a paper by Piet Hut (from Princeton)
   >                         . . . .
   >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

Is this intended to convince anyone of anything?  Of course it will come
apart in time -- eveything does.  The question is: if this mythical companion
had been formed along with our solar system, could it have survived until
now? (i.e. is this idea totally impossible, or merely wildly improbable?)

A 20% slop in period ought to cover virtually any funny-looking peaks in a
power spectrum dominated by noise, and allow true believers to "save the
hypothesis" without too much trouble.  

I've seen more convincing evidence for the Great Pumpkin.


-- 
                                 Ed Nather
                                 {allegra,ihnp4}!{ut-sally,noao}!utastro!nather
                                 Astronomy Dept., U. of Texas, Austin

Re: Stability of the 'Nemesis' system

#38

Author: William L. Sebok
Date: Tue, 05 Jun 1984 03:41

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With any luck the Institute for Advance Study's vax will begin to get
net.astro.expert this summer.  Then Dr. Piet Hut can discuss Nemesis
in person if he wishes.
-- 
Bill Sebok			Princeton University, Astrophysics
{allegra,akgua,burl,cbosgd,decvax,ihnp4,kpno,princeton,vax135}!astrovax!wls

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