Stars are separated by telescope
see two sets of spectral lines Doppler Shifted
Stars cross in front of one another
Kepler's first law
orbits are elliptical
Kepler's second law
equal areas in equal time.
Kepler's third law
Harmonic Law; P^2 = a^3 / Ma+ Mb
when star is slowest
when star is fastest, usually on end star is closest to
What is the relationship between luminosity and mass?
Luminosity is proportional to Mass to the 3.5 power
How do you find out the lifetime of a star?
T = 1/M^2.5
Which kind of stars evolve faster?
more massive stars
What makes a cloud collapse?
What are two hindrances to collapsing?
Internal Heating and Angular Momentum
What is internal heating?
causes pressure build up which, kinetic energy pushes the cloud back
What is angular momentum?
It causes high speeds, which means cloud has to expand to slow down
What are the three collapse methods?
Accretion, Gravity and radiation pressure, supernova blast waves
How is the collapse halted?
By the pressure of the heated gas and radiation which counteract gravity
What is fusion?
Creating heavier elements from lighter ones
How do main sequence stars release energy?
By converting hydrogen into helium
What is the most efficient nuclear reaction in a lower mass star?
What is the most efficient nuclear reaction in a higher mass star?
What is an open cluster?
Does fusing light elements require energy?
Does breaking up (fission) of heavy elements require energy?
What's the trend of luminosity and temperature on the main sequence?
Increases as it heads towards O
What temperature is an O star?
What temperature is a B star?
What temperature is an A star?
What temperature is an F star?
What temperature is a G star?
What temperature is a K star?
What temperature is an M star?
Where are there more heavy metals? In Population 1 or 2?
In population 1
In what bands of the electromagnetic spectrum is the atmosphere transparent?
Visible and Radio (mm-cm)
What population is high metallicity a property of?
Population I (young stars)
What defines when a "star is born"
Whenever fusion starts
What temp does hydrogen lines occur
what temp does molecular lines occur
what temp does ionized helium lines occur
what temp does neutral metals occur
what temp does helium lines occur
What is absolute magnitude (M)
magnitude a star would have at 10 pc
what is apparent magnitude (m)
magnitude a star would have from its actual location
what is bolometric magnitude
absolute magnitude summed over all wavelengths
What are the intrinsic properties of a star?
absolute magnitude and bolometric magnitude