10. Stellar Nurseries

Last: 9. How Far the Stars? Next: 11. Origin of the Elements

Stars are born inside great clouds of cool gas and dust. Such a cloud may contain thousands of denser lumps of gas; some of these lumps collapse under their own weight. This gravitational compression heats the gas until thermonuclear reactions can occur. When the production of nuclear energy matches the rate at which energy escapes into space, the collapse halts and a main-sequence star is born.

Topics:

Reading:

    Ch. 9PROTOSTARS AND PRE-MAIN-SEQUENCE STARS (p. 182)
    Ch. 9-1Stars condense from clouds of gas and dust
    Ch. 9-2Supernova explosions in cold, dark nebulae trigger the birth of stars
    Ch. 9-3When a protostar ceases to accumulate mass, it becomes a pre-main-sequence star
    Ch. 9-4The evolutionary track of a pre-main-sequence star depends on its mass
    Ch. 9-5H II regions harbor young star clusters
    Ch. 9-6Plotting a star cluster on an H-R diagram reveals its age
    Ch. 9MAIN-SEQUENCE STARS AND GIANT STARS (p. 191)
    Ch. 9-7Stars spend most of their life cycles on the main sequence

Web Resources:

Homework 10: Main-Sequence Stars, due 11/06.

Quiz 10: How Hot The Sun?, given 11/01.


Joshua E. Barnes (barnes@ifa.hawaii.edu)

Last modified: November 13, 2001
http://www.ifa.hawaii.edu/~barnes/ast110/sn.html