AST 112 - HW Chapter 18

Chemical composition

Determine which lines are present in the spectrum.

How does the mass of the Sun compare with that of other stars in our local neighborhood? A) We do not have enough information about the other stars in our local neighborhood B) The Sun is one of the least massive stars in our local neighborhood C) The Sun is approximately the same mass as most of the stars in our local neighborhood D) The Sun has approximately the same mass, but a smaller radius than most of the stars in our local neighborhood E) The Sun is one of the most massive stars in our local neighborhood

E) The Sun is one of the most massive stars in our local neighborhood

Radial Velocity

Measure the Doppler shift in the spectrum.

Luminosity

Measure the apparent brightness and compensate for distance.

Diameter

Measure the light curves and Doppler shifts for eclipsing binary stars.

Mass

Measure the period and radial velocity curves of spectroscopic binary stars.

Surface Temperature

Measure the spectrum and get the spectral type.

Rotation

Measure the width of spectral lines.

spectroscopic binary

a binary star in which the components are not seen separately, but whose binary nature is indicated by periodic variations in radial velocity, indicating orbital motion

visual binary

a binary star in which the two components are telescopically resolved

eclipsing binary

binary star in which the plane of revolution of the two stars is nearly edge-on to our line of sight, so that periodically, one star blocks the light of the other by passing in front of it

binary stars

two stars that revolve about each other

You are able to take spectra of both stars in an eclipsing binary system. Select all properties of the stars that can be measured from their spectra and light curves. A) Masses B) Radial velocities C) Luminosities D) Chemical composition E) Radii/diameters

B) Radial Velocities D) Chemical Composition

The H-R diagram depicts the relationship between which two stellar parameters? A) Spectral Type and Temperature B) Luminosity and Absolute Magnitude C) Luminosity and Temperature D) Color and Radius E) Mass and Temperature

C) Luminosity and Temperature

Which of the following statements about binary systems is FALSE? A) Spectroscopic binaries must have rather high orbital velocities so that the effect of this motion is clearly identifiable in the spectrum. They tend to have short periods. High orbital velocity occurs with long periods and large major axes only if the stars are very massive. B) In order to detect a spectroscopic binary, we need only detect changes in velocity associated with orbital motion. The plane of the orbit of the binary system can be in any orientation except exactly perpendicular to the line of sight. C) There are fewer spectroscopic binaries than eclipsing binaries. It is much more likely that a binary system will be oriented in such a way that we can detect detect eclipses than that it will be oriented exactly right for us to see orbital motion.

C) There are fewer spectroscopic binaries than eclipsing binaries. It is much more likely that a binary system will be oriented in such a way that we can detect detect eclipses than that it will be oriented exactly right for us to see orbital motion.