1. Stars
Expectations: D2.3, D2.5,

2. How do Stars Differ? Size Mass
Brightness /Luminosity: is a measure of the total amount of energy radiated by a star or other celestial object per second
Composition
Temperature
Colour

3. Different Stars

4. More Massive Stars

5. Life Cycle of Stars
Nebula: birthplace of a star, made of gas and dust

6. The life of a star is determined by its mass.
The more massive the star, the faster its rate of nuclear fusion and therefore a shorter life.

7. Hertzsprung-Russell Diagram

8. Composition of Stars Spectral Analysis
Astronomers can use spectroscopes to identify the composition of stars
Each element has a unique set of absorption/emission lines.

9. Composition of Stars Spectral Analysis
Here are spectra for some elements common in the atmospheres of stars:
Here are the spectrums of mystery stars: 1 2 3

10. Composition of Stars Spectral Analysis
Here are spectra for some elements common in the atmospheres of stars:
Here is the spectrum of a mystery star: 1
has the following elements: Iron Magnesium 2
has the following elements: Iron Calcium 3
has the following elements: Iron Calcium Hydrogen

11. Comparing Stars and Planets
A star is matter that emits huge amounts of energy.
A planet is matter, generally spherical, that revolves around a star.
Feature
Planet
Star
Location
In the solar system
Beyond the solar system
Distance from Earth
Fairly near
Very far
Real size
Smaller than most stars
Usually larger than planet
Reason we see object
Reflects Sun’s light
Emits its own light
Surface temperature
Usually cool or very cold
Very hot
What object is made of
Usually rocks or gases
Gases under high pressure
& temperature
Observable feature
Has a steady light
Appears to twinkle
Long-term observable
feature
Very slowly wanders
through constellations
Appears to move through
sky as part of a constellation

12. Classwork Worksheets (HR diagram & Life Cycle of Stars)
Read p
Answer page 373 #1-3, 5, 7-9
Read p
Answer page 382 #3-4, 6, 7, 9