What is absolute magnitude?

How bright a star would look at a standard distance of 10 parsecs

What causes the parallax shift of a nearby star?

The Earth's motion around the Sun

Their period of pulsation gives their true brightness

Regular dips as one star passes in front of the other

12questions. Pick an answer and you'll see why right away.

On the magnitude scale, which objects have the smaller (or negative) numbers?
What is absolute magnitude?
A star has apparent magnitude m = 6 at a distance of 100 parsecs. Using M = m + 5 - 5 log d, what is its absolute magnitude?
How does the apparent brightness of a star change if its distance is doubled?
Which of these can be found from a star's spectrum?
What colour are the hottest stars?
On the Hertzsprung-Russell diagram, which way does the temperature axis increase?
Where on the HR diagram do white dwarfs lie?
A star has a parallax angle of 0.25 arcseconds. What is its distance in parsecs?
What causes the parallax shift of a nearby star?
Why are Cepheid variables useful for measuring distance?
What does the light curve of an eclipsing binary show?