Ch. 17 Flashcards
Star Color / Temp
Blue = hotter
(+White, +Yellow, + Orange)
Red = colder
Brightness / Magnitude
Larger magnitude = lower brightness
Apparent Brightness
The amount of energy that happens to reach our eyes or a telescope on Earth
Luminosity
Total amount of energy at all wavelengths that it emits per second
William & Margaret Huggins
First to identify lines in the spectrum of a star other than the Sun using spectrogram
Spectral Class of Stars
(hottest) OBAFKGKM (coolest)
- 10 subcategories
Absorption Lines
O Stars: ionized helium
A Stars: hydrogen lines
F Stars: ionized metals
M Stars: titanium oxied
Spectral Class of Stars
(hottest) OBAFKGKM (coolest)
- 10 subcategories w/numbers 0-9
Annie Jump Cannon
Created classification of stellar spectra
Brown Dwarfs
Masses intermediate between stars and planets; difficult to observe because faint + cool // spectral classes L, T, and Y
Dwarf Stars
Differ from typical stars due to different fusion process
Spectral Lines
Useful for when stars have same temperature but different pressure (low - narrow, high - broad)
Doppler-Shifted Stars
Red: star moving away
Blue: moving toward us
Proper Motion
Transverse from doppler; moves across our line of sight
Barnard’s Star
fastest moving star
Henry Draper
First person to successfully photograph the spectrum of a star; wife gave several $100,000 to Harvard Observatory
Giant Star
- Large, extended photosphere
- Low density particles
- Low pressure
- Narrower spectral lines than star of same temperature
- More ionized atoms
Space Velocity
Total speed and direction in which it is moving through space relative to the Sun
Rotation
If star is rotating rapidly, greater spread of Doppler shifts and all spectral lines should be broad // speed decreases at it ages
James Lick
Philanthropist that provided funds for 36 inch refractor telescope
