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From: hogg@utcsri.UUCP (John Hogg)
Newsgroups: net.astro
Subject: Comet lifespans
Message-ID: <1829@utcsri.UUCP>
Date: Fri, 20-Dec-85 10:35:02 EST
Article-I.D.: utcsri.1829
Posted: Fri Dec 20 10:35:02 1985
Date-Received: Fri, 20-Dec-85 11:20:20 EST
Reply-To: hogg@utcsri.UUCP (John Hogg)
Organization: CSRI, University of Toronto
Lines: 23

Comets are highly visible because a proportion of their mass is spread
across an appreciable region of space at each pass.  This implies that they
eventually wear out.

Can any of the experts reading this group tell me typical or range values
for the following?
	
	a) initial comet mass and size
	b) loss of mass and size at each orbit
	c) number of orbits with "significant" tail
	d) final mass and size, assuming a "dead" core exists (does it?)

Or to be more specific: when is Comet Halley likely to wear out, presuming
that we don't accidentally take it out with a probe first?
-- 

John Hogg
Computer Systems Research Institute, UofT
...utzoo!utcsri!hogg

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