Exam 13: Taking the Measure of Stars

You observe a binary star system and find that star 1 has a velocity of 20 m/s while star 2 has a velocity of 40 m/s.What is the ratio of masses of the two stars ? If you find that the separation of the two stars is 0.5 AU and the orbital period is 70 days,then what are the individual masses of the two stars?

It is not possible to detect a measurable parallax for even the closest stars without the use of a telescope.

Mass determines the position of a star on the main sequence.

A star with the same luminosity as the Sun,but which is twice as hot,must be four times as big.

How is the unit of length known as a parsec defined?

If we measure a star's luminosity and temperature,what other property of the star can we calculate? Explain how.

Star A is exactly the same color as star B and appears equally bright.Through stellar parallax we find that star B is twice as far away from us as star A.Determine which star has the largest radii and how much larger it is.

You discover a binary star system in which star A has a velocity of 10 km/s and star B has a velocity of 30 km/s.If you study the system further and find out that the orbital period is 30 days and the orbital separation is 0.3 AU then what are the masses of stars A and B?

Parallax is used to measure

The spectral class of a star is related to its

If a star's measured parallax is 0.2 arcsec,what is its distance?

Rigel is a star with an apparent magnitude of +0.1,and Betelgeuse is a star with an apparent magnitude of +0.4.Which star appears brighter,and what is the ratio of their brightnesses?

B stars are cooler than M stars.

When looking at a standard H-R diagram,the hottest stars are on the left-hand side of the diagram.

Stars X and Y are 5 AU apart from each other.Star X is 4 times as massive as star Y.The center of mass of this system is __________ AU away from star X and __________ AU away from star Y.

The faster-moving star in a binary is

Explain how we can use spectroscopic parallax to determine the distance to a star farther away than a few hundred light-years.

In a binary star system that contains stars with and ,the velocity of the star will be __________ times the velocity of the star.

Eclipsing binary systems

If a star's distance is 10 pc,what is its parallax?