1. The Properties of Stars
Seven properties of Stars

2. The Seven Properties of a Star
Luminosity
Temperature
Distance
Composition
Radius
Mass
Radial Velocity

3. Luminosity & Brightness
How “bright” a star is can be measured 3 ways.
Apparent Magnitude is how bright a star appears to us on Earth
Absolute Magnitude is how bright a star would be if it was at a standard distance.
Both of these measure the amount of visible light coming from the star.
Luminosity is the total amount of E-M radiation (Visible light, X-rays, etc.) the star gives off

4. Temperature
The temperature of a star’s surface is usually measured in Kelvin
It can be calculated by measuring the intensity of its E-M radiation (including light) at different wavelengths.

5. Distance The distance is how far it is to the star
Usually measured in Light Years or Parsecs
Calculated by either the Parallax or Standard Candle Methods

6. Composition
The Composition of Stars is, of course what they are made of.
We find it by studying spectra
Mostly they are Hydrogen and Helium…
The exact amount of each establishes what “age” a star is.

7. Radius and Mass Radius measures the size of the star.
It is found by comparing Luminosities
Mass measures the amount of material in a star and its gravitational potential.
The mass of a Star determines its “life-span” and fate

8. Radial Velocity
Radial Velocity is how fast a star is moving toward or away from us.
The Doppler Effect, Red and Blue Shifts of color are used to find this velocity
By looking at the shift in the emission or absorption spectra pattern of an element.