# Compare the density of a white dwarf to a supernova.8. It would seem that a bright star is closer to earth than a dim star. But this is not always the case. What other factor could explain a...

Compare the density of a white dwarf to a supernova.

8. It would seem that a bright star is closer to earth than a dim star. But this is not always the case. What other factor could explain a difference in brightness?

9. Explain how absolute magnitude compares the brightness of stars.

10. What are the two characteristics that the H-R diagram plots against each other?

bandmanjoe | Middle School Teacher | (Level 2) Senior Educator

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The density of a white dwarf is less than that of a supernova.  While both these stages represent the end of the lifecycloe of a star, a white dwarf has less solar mass than a supernova.  Sometimes a supernova can turn into a neutron star, where the mass is so dense, a teaspoon of it brought back to Earth would weigh several tons!

For #8, if a star is undergoing a supernova type of explosion, the surrounding area of space could be brilliantly illuminated for several days.  It might be much further away than a closer, yet dimmer star, but looks closer because of the excessive light show.

For #9, there are two types of magnitude, which is star brightness:  apparent and absolute.  Apparent magnitude is what it looks like as you are looking at it with your eyes.  Absolute is the correct measure of brightness, scaled with a spectroscope.  The smaller the number, the brighter the star, so a star with a -4 is brighter than a +7.

And finally, #10, the two aspects the Hertzsprung-Russell diagram compares are star temperature and brightness, or magnitude.  Different temperature stars will give different colors, blue being the hottest and red being the coolest.  Our sun is in-between, a medium yellow star.

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