y12

The life cycle of stars

You are to produce a document to cover life cycle of stars of different masses.

You can email this to me, instead of printing.

Lots of information here http://www.astronomynotes.com/ and here http://bcs.whfreeman.com/universe6e/default.asp

Star birth

Perform a web search for giant molecular clouds, (The Eagle nebula and Orion Nebula are good examples). Insert a picture and add a caption.

“Giant molecular clouds are strung like pearls along the spiral arms of galaxies.”

Find a picture of a spiral galaxy. Hot blue stars are short lived so any we see are young. Note the blue light from the spiral arms.

Evidence of darker denser clouds can be seen in the horsehead nebula and other Barnard nebulae. Bok globules are even denser.

Protostars emit strongly in the infrared. You will find images at http://www.ipac.caltech.edu/Outreach/Edu/sform.html

Main Sequence.

There are many pictures of the sun and a search for Pleiades will give you and idea of a newly formed stellar cluster. Don’t forget the dim red ones.

The sun’s energy arises form nuclear fusion. Describe the fusion processes.

An animation may be found at this site in the chapter on the sun.

http://bcs.whfreeman.com/universe6e/default.asp

Choose animations and then complete list by chapter. There also animations on star birth you may view.

End States.

The sun will expand to a red giant before collapsing to a white dwarf (with a planetary nebula) you will find some good pictures of planetary nebulae.

Heavier stars will pass through the red giant stage before going supernova. Depending on its mass the core remnant will collapse into a neutron star or stellar black hole. The most famous supernova remnant is the crab nebula that contains a pulsar (a rapidly spinning neutron star). There are some excellent pictures of the crab and also x ray images of the neutron star which you should add to your account.

For obvious reasons there are no pictures of black holes but some excellent diagrams to look at.