From:    Dave Knapp
To:      All                                    Msg #336, Jul-15-93 03:23PM
Subject: SN1987A Distance

Organization: Laboratory for Experimental Astrophysics
From: dk@imager (Dave Knapp)
Message-ID: <224osk$g44@lll-winken.llnl.gov>
Newsgroups: talk.origins

   Since the distance to SN1987A has recently come up, and since
I am the one who (as far as I know) first introduced it into the
creation/evolution debate, I decided it was time to actually go
out and get some decent references.

   The reference I originally had was:

  "Ring Around SN1987A Supernova Provides a New Yardstick,"
  Physics Today, Feb. 1991 p. 20.

   This work has now appeared in a peer-reviewed journal:

  "Properties of the SN1987A Circumstellar Ring and the Distance
   to the Large Magellanic Cloud," by N. Panagia et al.,
   Astrophysical Journal _380_, L23-L26 (1991).

   Using a ring of material surrounding the supernova remnant,
the distance was geometrically determined to be 51.2 +/- 3.1 kpc,
or about 167,000 ly with an error of about 6%.

   Unfortunately for young-Earth creationists, the error makes it
essentially impossible to support a decaying-speed-of-light
argument.

   There are a few other related articles for the obsessively
interested:

   Fransson et al., Ap. J. _336_, 429-441 (1989)
   Crotts, Kunkel, and McCarthy, Ap. J. _347_, L61-L64 (1989)
   Bond et al., Ap. J. _354_, L49-L52 (1990)
   Jakobsen et al., Ap. J. _369_, L63-L66 (1991)