9. How Far the Stars?

Topics:

Reading:


Ch. 8-1	Distances to nearby stars are determined by stellar parallax
Ch. 8-2	Apparent magnitude measures the brightness of stars as seen from Earth
Ch. 8-3	Absolute magnitudes do not depend on distance
Ch. 8	THE TEMPERATURE OF STARS (p. 170)
Ch. 8-4	A star's color reveals its surface temperature
Ch. 8-5	A star's spectrum also reveals its surface temperature
Ch. 8-6	Stars are classified by their spectra
Ch. 8	TYPES OF STARS (p. 173)
Ch. 8-7	The Hertzsprung-Russell diagram identifies distinct groups of stars
Ch. 8-8	Luminosity classes
Ch. 8-9	A star's spectral type and luminosity class provide a second distance-measuring technique

Web Resources:

Hipparcos Results
The Hipparcos satellite measured positions and parallaxes for thousands of stars with enormous accuracy.
The Star Mapper
A superb essay by Philip Morrison describing early measurements of stellar parallax and contrasting them with Hipparcos. Highly recommended!
The Solar Neighborhood (3 Mbyte gif animation)
Animation of the 150 nearest stars, made using Hipparcos data. Color indicates stellar luminosity: blue stars are above 10 L, yellow stars are between 1 and 10 L, orange stars are between 0.1 and 1 L, and red stars are below 0.1 L.

Homework 9: Finding Distance With Parallax, due 10/30.

Quiz 9: Is The Sun A Star?, given 10/25.

Last modified: October 25, 2001
http://www.ifa.hawaii.edu/~barnes/ast110/hfts.html