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Chapter 28 Notes Section 2
What is a constellation?
A group of stars that appear to form a pattern in the sky
How many constellations can be seen from the northern and southern hemispheres?
88
What is another name for constellations that can be seen all year long?
Circumpolar
What are some of those constellations?
Ursa Minor (Little Dipper), Ursa Major (Big Dipper), Cassiopeia
Why can’t we see Orion in June?
Because of Earth’s movement around the sun
Apparent Magnitude – What is it?
How bright a star appears to be to an observer on Earth.
As a star is determined to be brighter than the number for apparent magnitude goes
DOWN. (The more negative the number, the brighter the star)
How many kilometers are there in an astronomical unit?
150 Million Km (93 million miles)
What is better to use when determining the distance to stars, kilometers, a.u. or light
years? Why?
Light years, it measures the distance that a ray of light travels in one year. It
measures greater distances.
What 2 elements are in every star? Hydrogen and Helium
The color of stars depends on the surface temperature of the star. The temperature range
for colors and the colors are shown in the table below. Fill in the missing information
temperature
color
Bluish White
9500 – 30,000 +
4000 - 7000
Yellowish
Red
Less than 3900
Luminosity depends on temperature and size but not distance (from sun or earth).
H-R diagram (page 626)
What is shown on the X-axis?
Temperature
What is shown on the Y-Axis?
Luminosity
What three colors are shown on the graph?
Blue, Red, Yellow
List the group names for the different stars?
Blue Super Giants, Red Giants, Red Super Giants, White Dwarfs, Main Sequence
(most stars are Main Sequence)
Describe the difference between a red supergiant and a blue supergiant.
Blue is hotter, Red is cooler (temperature)
With the drawing on page 628-629 describe the 2 paths a star may take during their
lifetimes.
What determines which path a start will take?
Size