Stellar Spectral Classification Flashcards
Order stellar spectra according to the strengths of their spectral lines
Identify the main physical property which distinguishes stars of different spectral types and describe how it gives rise to the patterns of spectral line strengths
Surface temp -
- cool stars dont have enough energy for electrons to sit at n=2 - most sit at ground state n=2
- star must be warm enough to have electrons sitting in n=2 to show balmer lines
- so most cool stars will have weak spectral
- warmer stars with electrons at n=2 can absorb red light
- hot stars electrons are almost all at n=2 they can absorb lots of red light
- hottest stars - hydrogen atoms might be completely ionizes/electrons waiting gin levels above n=2
Come up with your own mnemonic for remembering the sequence of stellar spectral types
Oll Bitches Are Fucking Gay Kill Me
Given two stellar spectra, identify which star is hotter
Discuss stellar masses in terms of the solar mass unit
They range from 0.08 to 150 Stellar mass units (Msun)
Most stars - small M and K red dwarfs are in the 0.08-0.5 stellar mass range
What do the luminosity classes tell us?
It tells us the range of luminosity - eg as you move down classes (5-1) the stars in these class have a shorter and shorter range of luminosity
Eg all class 1a super giants have the same luminosity
What are the luminosity classes
1 - supergiants
2 - bright giants
3 - giants
4 - sub giants
5 - main sequence