This chart arranges stars into bands according to where they are in their lifetimes, grouped by spectral class and luminosity.
What is the Hertzsprung-Russell diagram?
100
The Roman numeral designators for luminosity classes.
What are I - V?
100
In this kind of binary star, we can see both components that make up the system.
What is a visual binary?
200
The brightness of a star as seen from a distance of 10 parsecs.
What is absolute magnitude, M?
200
The letter designations for spectral classes, from hottest to coolest.
What is O, B, A, F, G, K, M?
200
The band in the H-R diagram that shows stars in the middle of their lifetimes, fusing hydrogen into helium.
What is the main sequence?
200
The Sun would be classified as this luminosity class.
What is Class V?
200
A binary system where the orbits of the stars carry them periodically in front of one another.
What is an eclipsing binary?
300
The amount of energy the star emits per second.
What is its luminosity?
300
The color we would perceive in an M-class star.
What is Red?
300
Stars in the upper right corner of the H-R diagram that are very cool but extremely luminous.
What are red (super) giants?
300
A red super giant would be in this luminosity class.
What is Class I (Ia or Ib)?
300
A binary system where we can not see the individual components even in a large telescope but we can detect its binary nature through regular shifts in absorption lines.
What is a spectroscopic binary?
400
A star with m = 4.0 is approximately this many times brighter than a star with magnitude 5.0.
What is 2.5 time brighter?
400
An O or B class star would have this color.
What is blue (blue-white)?
400
A medium-sized star that has exhausted all its fuel and shrunk to a tiny cinder.
What is a white dwarf?
400
White dwarf stars are in this luminosity class.
What is they are not assigned luminosity classes because they are not fusing elements in their cores?
400
A binary star's light curve where we see alternating dips of larger and smaller magnitudes tells us this about the star system.
What is the stars have different brightness?
500
The reason we use absolute magnitude to compare the brightness of two stars.
What is:
Brightness changes with distance.
A dim, close star might appear brighter than a more luminous but distant star.
We put stars at same distance to remove this effect.
500
Hydrogen alpha, beta and gamma absorption lines are most prominent in the spectra of stars with temperature around 9000 K, corresponding to this spectral class.
What is a class A star?
500
A main sequence star with a luminosity 10^4 times that of the Sun will have approximately this temperature.
What is 35,000 - 40,000 K?
500
If you have a star with spectral class given as M0 III, it would have this absolute magnitude.
What is approximately M = 0?
500
Not considered a true binary system, these stars simply share the same line of sight but are at different distances from the Earth.