Astronomy a beginners guide to the universe 8th CHaisson mcmillan chapter 10 clicker questions

The angle of stellar parallax for a star gets larger as the... The angle of stellar parallax for a star gets larger as thed length of the baseline increases.. You can best model the size

Stellar parallax is used to measure the

Stellar parallax is used to measure the

The angle of stellar parallax for a star gets larger as the

The angle of stellar parallax for a star gets larger as the

d) length of the baseline increases.

Explanation: Astronomers typically make

observations of nearby stars 6 months

apart, making the baseline distance

equal to 2 AU (astronomical units)

You can best model the size and distance relationship of our Sun and the next nearest star using

You can best model the size and distance relationship of our Sun and the next nearest star using

d) two golf balls 100 km apart.

Explanation: The Sun is about 1 million miles in diameter The next nearest star is about 25 million times farther away

A star’s proper motion is its

opposite sides of Earth’s orbit every 6 months

across the sky

us, revealed by Doppler shifts

A star’s proper motion is its

opposite sides of Earth’s orbit every 6 months

c) annual apparent motion

across the sky.

us, revealed by Doppler shifts

Explanation: A star’s “real space motion” combines its apparent proper motion with its radial motion toward or away

from Earth

In the stellar magnitude system invented by Hipparchus, a smaller magnitude indicates a _ star.

In the stellar magnitude system invented by Hipparchus, a smaller magnitude indicates a _ star.

A star’s apparent magnitude is a number used to describe how our eyes measure its

A star’s apparent magnitude is a number used to describe how our eyes measure its

The absolute magnitude of a star is its brightness as seen from a distance of

The absolute magnitude of a star is its brightness as seen from a distance of

standard for specifying and

comparing the brightnesses of stars

Which of the following quantities do you need in order to calculate a star’s luminosity?

Which of the following quantities do you need in order to calculate a star’s luminosity?

e) Both a and d are correct.

What are the two most important intrinsic properties for classifying stars?

What are the two most important intrinsic properties for classifying stars?

temperature

b) Luminosity and surface

temperature

Explanation: The H–R diagram plots

stars based on their luminosities and

surface temperatures

Wien’s law tells us that the hotter an object, the _ the peak wavelength of its emitted light.

Wien’s law tells us that the hotter an object, the _ the peak wavelength of its emitted light.

Explanation: Wien’s law

states that hotter stars

appear more blue in color,

and cooler stars appear

more red in color

We estimate the surface temperature of a star by using

lines in its spectrum

as measured through red and blue filters

We estimate the surface temperature of a star by using

lines in its spectrum

as measured through red and blue filters

e) All of the above are used.

Which spectral classification type corresponds to a star like the Sun?

Which spectral classification type corresponds to a star like the Sun?

Explanation: The OBAFGKM

classification scheme is based

on absorption lines

The key difference between the spectra of B stars and

G stars is

The key difference between the spectra of B stars and

G stars is

a) B stars show strong hydrogen lines; G stars show weaker hydrogen lines.

metal atoms

hydrogen atoms

Explanation: The original OBAFGKM sequence was arranged alphabetically by the strength of hydrogen absorption lines B stars had strong hydrogen lines; G stars had weak lines

Astronomers can estimate the size of a star using

Astronomers can estimate the size of a star using

diameter

e) a, b, and c are all true.

Explanation: Brightness and

temperature are used to plot the

star on an H–R diagram and

indicate its approximate size

Some stars are large enough to

measure directly

Eclipsing binary stars are very useful for determining the

Eclipsing binary stars are very useful for determining the

Explanation: Analysis of the light curve of an eclipsing binary star system can reveal the masses of the stars

What is the single most important characteristic in determining the course of a star’s evolution?

What is the single most important characteristic in determining the course of a star’s evolution?

Explanation: A star’s mass

determines how fast it forms,

its luminosity on the main

sequence, how long it will shine,

and its ultimate fate