How did astronomers discover the relationship between spectral type and mass for main sequence stars?
By measuring the masses and spectral types of main-sequence stars in binary systems.
The choices below each describe the appearance of an H-R diagram for a different star cluster. Which cluster is the youngest?
The diagram shows main-sequence stars of every spectral type except O, along with a few giants and supergiants.
The choices below each describe the appearance of an H-R diagram for a different star cluster. Which cluster is most likely to be located in the halo of our galaxy?
The diagram shows main-sequence stars of spectral types G, K, and M, along with numerous giants and white dwarfs.
You observe a star and you want to plot it on an H-R diagram. You will need to measure all of the following, except the star's
To calculate the masses of stars in a binary system, we must measure their
orbital period and average orbital distance
Sirius is a star with spectral type A star and Rigel is a star with spectral type B star. What can we conclude?
Rigel has a higher surface temperature than Sirius.
The star Vega has an absolute magnitude of about 4 and an apparent magnitude of about 0. Based on the definitions of absolute and apparent magnitude, we can conclude that
Vega is nearer than 10 parsecs from Earth.
Star A is identical to Star B, except that Star A is twice as far from us as Star B. Therefore:
Both stars have the same luminosity, but the apparent brightness of Star B is four times that of Star A.
Based on the definition of apparent brightness, which units are appropriate for its measurement?
watts per square meter