Exam 9: The Family of Stars

Remember Kepler's third law, which relates the period of revolution to the average distance to a planet.   How do we modify that law to use with binary stars?

Recently discovered brown dwarfs have spectra similar to cool O-type stars.

The horizontal axis in the accompanying figure is labeled _____.

The Hertzsprung-Russell Diagram is a plot for stars using absolute magnitude versus temperature.

Which star has the largest diameter?

S tars of low luminosity will always have large positive absolute magnitude.

If luminosity depends on radius and temperature, what does flux depend on?  _______________

A star has a parallax angle of 0.019 seconds of arc.  How far away is this star from Earth?

The Balmer series of hydrogen absorption lines in stars is located in what part of the electromagnetic spectrum?

Recent discoveries of two types of brown dwarfs have placed these stars near which spectral type of star?

The most common stars are _______________ stars.

All stars produce an absorption spectra.

Which star has the highest density (mass per unit volume)?

Th e apparen t magnitud e o f a sta r observe d fro m a distanc e o f 1 0 pc is called _____.

In the accompanying figure, which region represents stars that are extremely bright and emit most of their radiation as ultraviolet light? Note: (C) represents the entire main sequence while (D) and (E) represent only small parts of the main sequence?

Explain why it would be better to obtain stellar parallax for stars if we could observe from the planet Mars instead of the Earth.

In which spectral sequence are the hottest stars categorized?

The luminosity class is assigned to a star by studying the absorption lines in the spectrum of the star.

The sloped lines from top left to bottom right in the accompanying figure are labeled ____.

The stellar parallax limit for ground-based telescopes is accurate for stars closer than ____.