Re: New Supernova paper

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> Just how do we test this
>hypothesis.  Ellis says rocks formed at the time of the P-T extinction may
>contain "unusual isotopes" of common elements.  Got to add those to your
>list Erwin.  Some guys just have all the luck!  ;)

Haven't read that paper yet, but I brought up the topic with an
astrophysicist doing his dissertation on some aspect of supernovae.  Here
is his response:

>        There would be a few obvious effects of our being that close to a
>supernova.  Fossil Aluminum 26 would probably be the easiest to find.  Just
>how
>close was the supposed supernova?  My quick, back of the envelop, calculation
>is
>that a supernova 5 light years away would, to an earth-based observer, be
>equivalent to a second sun.  It would last for a few months. To get
>catastrophic
>effects you would have to get closer (The effects would go as r^-2).  However,
>I
>would expect a supernova even this close to leave a pretty clear isotopic
>record.
>In particular, minerals containing alot of aluminum should contain excesses of
>Magnesium 26.  These should be deposited after the supernova (You need time to
>get
>here) but at most about 1Myr later (The lifetime of Al26).  Of course, the
>further
>away the less Al26.  I'm not sure about where the limiting distance would be
>before we couldn't detect any.

        	        	
Thomas R. Holtz, Jr.    	       	       	       tholtz@geochange.er.usgs.gov
Vertebrate Paleontologist in Exile      	    Phone:  	703-648-5280
U.S. Geological Survey  	       	       	      FAX:    	703-648-5420
Branch of Paleontology & Stratigraphy
MS 970 National Center
Reston, VA  22092
U.S.A.