Download Stars and Galaxies Section 1 Stars

T2 Stars and Galaxies
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Stars and Galaxies
Section 1 Stars
A. Patterns of stars - constellations
1. Ancient cultures used mythology or everyday items to name
constellations
2. Modern astronomy studies 88 constellations
3. Some constellations are not visible all year because Earth revolves around the Sun
4. Circumpolar constellations in the northern sky appear to circle around Polaris and are
visible all year
B. Star magnitude
1. Absolute magnitude—measure of the amount of light a star actually gives off
2. Apparent magnitude—measure of the amount of a star’s light received on Earth
C. Space measurement
1. Astronomers measure a star’s parallax—shift in its position when viewed from two
different angles
2. Distance is measured in light-years—the distance light travels in a year
D. Star properties
1. Color indicates temperature
a. Hot stars are blue-white
b. Cool stars look orange or red
c. Yellow stars like the Sun are medium temperature
2. A spectroscope breaks the visible light from a star into a spectrum
a. Spectrum indicates elements in the star’s atmosphere
DISCUSSION QUESTION:
Why are circumpolar constellations always visible? Because of their unique position,
these stars are
visible in the northern sky each sesaon; other constellations, such as Orion—visible in
the winter
months—are not always visible.
Underlined words and
phrases are to be filled
in by students on the
Note-taking Worksheet.
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