AST 220 CH. 10 EXAM QUESTIONS WITH COMPLETE SOLUTIONS

AST 220 CH. 10 EXAM QUESTIONS WITH
COMPLETE SOLUTIONS


A parsec is about 3.3 light-years. - ANSWER True

A parsec is slightly more than 200,000 AU. - ANSWER True

The nearest star system to our Sun, Alpha Centauri, is still over a parsec distant. -
ANSWER True

If a star has a parallax of 0.25", then its distance is about 13 light-years. - ANSWER True

Fewer than 100 stars lie within 5 parsecs of the Sun. - ANSWER True

Almost all properties of other stars are described relative to our Sun. - ANSWER False

Combining a star's proper motion and its distance allows us to determine its transverse
velocity. - ANSWER True

The parallactic angle is the total shift observed over a six-month interval. - ANSWER
False

Most stars are single stars like our own. - ANSWER False

Our nearest stellar neighbor is a little less than 1 parsec away. - ANSWER True

Of all the stars in the sky, Barnard's star, the next closest beyond Alpha Centauri,
appears to move the fastest. - ANSWER True

Two stars have the same absolute magnitude, but one lies twice as far from Earth as the
other. It will appear half as bright. - ANSWER False

The Sun, at absolute magnitude +4.8, would be one of the brightest stars in the sky if
seen from 32 light-years distance. - ANSWER False

A +6.0 magnitude star appears 2.5 time brighter than a +3.0 magnitude star. - ANSWER
True

A 3rd magnitude star appears 2.5 times brighter than a 4th magnitude star. - ANSWER
True

At its brightest, Venus, at magnitude -4 is 100 times brighter than a 1st magnitude star. -
ANSWER False

A type B9 star is hotter than a type A0 star. - ANSWER True

A type B star is bluer than a type G star. - ANSWER True

, Hydrogen lines are strongest in class A stars. - ANSWER True

A unique characteristic of type O stars is ionized helium lines in its spectrum. - ANSWER
True

Only type A stars show hydrogen lines in their spectra. - ANSWER False

Hydrogen lines are weak in M class stars because they have much less of it than do A
class stars. - ANSWER False

Spectroscopic parallax is more accurate than trigonometric parallax for nearby stars. -
ANSWER False

Molecular lines, such as TiO, are only found in very hot stars. - ANSWER False

A star of the same diameter, but twice as hot as our Sun, must be 16 times more
luminous. - ANSWER True

White dwarfs lie on the lower left portion of the H-R diagram. - ANSWER True

Almost all stars on the main sequence range from 1 to 10 solar luminosities. - ANSWER
False

Most naked-eye stars would fall at the top left on the H-R diagram. - ANSWER True

The vast majority of stars near us would fall to the bottom right on the H-R diagram. -
ANSWER True

Main sequence stars lie at the top right corner of the H-R diagram. - ANSWER False

Our Sun lies about the middle of the main sequence and the H-R diagram. - ANSWER
True

Main sequence stars are fusing hydrogen into helium in their cores. - ANSWER True

Almsot all stars on the main sequence range from 0.1 to 15 solar radii. - ANSWER True

Luminosity class V stars are larger than class Ia stars. - ANSWER False

The main sequence is luminosity class V. - ANSWER True

A G2V star would be the same temperature as a G2Ib star, but much smaller and less
luminous. - ANSWER True

The pressure in the photosphere affects the width of spectral lines. - ANSWER True

The mass of a newly formed star will determine its position on the main sequence. -
ANSWER True

Our best stellar parallax measurements to date come from - ANSWER the Hipparcos
satellite