(fwd) [vsnet-chat 1573] Re: (fwd) query on SN IIn (Richmond) From richmond@a188-l009.rit.edu Tue Jan 26 00:44 JST 1999 Subject: Re: [vsnet-chat 1573] Re: (fwd) query on SN IIn Date: Mon, 25 Jan 1999 10:47:02 -0500 From: Stupendous Man <richmond@a188-l009.rit.edu> As I understand it, the "IIn" events do show narrow lines of hydrogen (and other low-ionization elements?) in their spectra. One explanation for this is that these SNe explode into a relatively thick circumstellar medium surrounding the star; this is postulated to be the remnants of an earlier phase of mass loss in a stellar wind (probably as a red giant). I think the idea is that when the ejecta slam into the pre-existing material, it excites the atoms in the material, which subsequently emit radiation. The material may also be excited by photo-ionization by the hot ejecta from the supernova. In fact, the latter is more likely, because the observed lines are NARROW: the material emitting those lines must be moving much more slowly than the ejecta. This is my somewhat confusing explanation. -- ----- Michael Richmond "This is the heart that broke my finger." mwrsps@rit.edu http://a188-L009.rit.edu/richmond/