Download Stellar Evolution: The Lives of Stars

Stellar Evolution: The Lives of Stars
Stars are not static (unchanging); they evolve, or change over time. They are “born”
from giant spinning masses of primarily H & He evolve through common stages and
“die” various deaths based on their mass. It is the crushing force of gravity on such great
mass that “sparks” the process of nuclear fusion. Stars lead short lives if they are massive
and long lives if not. Their “deaths” also depend on their original mass. Recall that
nuclear fusion is an outward force that counteracts the crushing force of gravity and
releases radiant energy (the continuous electrical magnetic spectrum) that makes stars
shine. On the back of this page draw two paths of stellar evolution in color pictures with
captions for the two stars the Sun, and Betelgeuse. Use the pictures on page 610-611 in
your textbook as examples of pictures and captions for drawing the two pathways.
What to Do:
1. First draw the path the Sun will take over about 10 billion years. The Sun is a low to
medium mass star and will eventually become a black dwarf. Draw a protostar forming
in a nebula then an arrow to the Sun as a medium size yellow star (don’t forget to add
sunspots!), then an arrow to a giant red star (the Sun will likely grow to the size of
Earth’s orbit!), then draw a beautifully colored planetary nebulae (use your imagination
to draw the star shedding gas into space leaving behind a small core, then an arrow to a
small white dwarf, and then an arrow to a small black dwarf. Don’t forget to include
written captions like on page 610-611!
2. Next draw the path Betelgeuse will take over about 1.5 million years. Betelgeuse is a
massive supergiant star that will eventually become either a neutron star or a black hole.
Draw a high-mass protostar forming in a nebula then an arrow to a large blue star, then an
arrow to a massive red supergiant star (Betelgeuse today!). Betelgeuse is so large if it
was in our solar system it would be the size of Jupiter’s orbit! Then draw an arrow to a
supernova, then draw two arrows showing a path to a black hole and a separate path to a
neutron star (like the picture on page 805) . Whether a massive star becomes a neutron
star or a black hole depends on its mass. Don’t forget to include written captions like on
page 610-611!
Betelgeuse is 600 light years from Earth and is easily seen in the constellation Orion, the
hunter. Orion is a northern hemisphere winter constellation in the southeast sky that rises
high overhead as night progresses. Betelgeuse is the bright red star that makes up the
hunters upper left shoulder. Betelgeuse has such a short life due to its massive size, about
300 times the mass of the Sun (it consumes its nuclear fuel very fast), and so it would
have been seen as a blue white star 10,000 years ago. Then over the period of human
civilization it turned white then yellow and finally red, as we see it today. Before the Sun
becomes a giant red star, Betelgeuse will have become either a neutron star or a black
hole (following the spectacular flash of a supernova!) both of which will leave a dark
spot where the hunter’s shoulder once was. Be sure to check out Orion and his
supergiant shoulder star Betelgeuse on any winter’s night before its gone forever!
Turn this paper in when it’s due for a grade! Your grade depends upon the quality and
accuracy of your drawings and captions.