Stellar Evolution

From pasta@u.washington.edu Mon Jul 22 17:14:11 1996
Date: Mon, 22 Jul 1996 17:14:07 -0700 (PDT)
From: Stephanie Kauk 
To: bbeck@astro.washington.edu
Subject: Week 6 contribution
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There were two website where I found interesting information about stellar
evolution.  One was
http://www.astro.psu.edu/deptinfo/research/Ground_Analysis/supernova.html

and
http://zebu.uoregon.edu/textbook/evergygen.html

One of the pages talked about fusion sequences in stars.  A temperature of
5 million degrees is required in order to fuse hydrogen into helium.  To
make elements with more protons in their nuclei it requires a higher
temperature.  An example that was given in the web page was carbon.  This
element requires a temperature of about 1 billion degrees.
The other page that I found dealt with supernovas.  Two results from the
explosion of supernovas are distribution of elements, as learned in class,
and the effects of the shock waves.  The shock waves from the explosions
may be responsible for causing the collapse of interstellar clouds into
new stars.  Supernovas occur in our galaxy once every hundred years.
There was a lot more information on these pages so check them out.

Stephanie




From unknown@heisenberg.phys.washington.edu Thu Jul 25 12:04:16 1996
Date: Thu, 25 Jul 96 19:04:14 0700
From: unknown 
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I looked up T Tauri stars as a subject for the stellar evolution 
assignment. T tauri stars are low mass pre-main sequence stars.  They 
are interesting because of the features they can have.  There is often a 
circumstellar disk of material left over from accretion and there are 
also sometimes two polar jets of hot gas.  I think they are called 
Herbig-Haro objects.  These stars are very young, and can tell us a lot 
about the processes that stars undergo during formation.  The jets are 
moving at huge speeds as measured by Doppler shifts.  Plus, they look 
really cool!



From sonicfan@u.washington.edu Sat Jul 27 23:51:01 1996
Date: Sat, 27 Jul 1996 23:50:58 -0700 (PDT)
From: Carl Stello 
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I found an interesting site at:

http://www.newwave.net/~applogic/nemesis.htm

The site is titled :On the Mechanics of Star Formation, Bianary Stars and
Nemesis."  The article is pretty brief, but from what I understand it
deals with enormous jets of material ejected along the axis of a newly
formed sun's accretion disk. According to the paper, these jets of
material are held in highly eccentric orbits perpendicular to the
accretion disk plane and may have orbital periods of millions of years.
The author mentions "Nemesis theory", which states a large body is in
orbit around our own sun with a period of 26 million years.  The author
then postulates that this body may be a red dwarf or supermassive planet
and could be responsible for the mass extinction of the dinosaurs.


Carl

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