Name: 

The hottest part of the Sun is the corona. _________________________

To measure long distances, astronomers use a unit of length equal to the distance light will travel in one year. Astronomers call it the astronomical unit. _________________________

Our sun is classified as a blue-colored star. _________________________

The phrase “a giant, hot ball of gases” best describes a:

The hottest part of the Sun is its:

Areas on the Sun representing cooler spots are called:

The source of the Sun’s heat and light energy is:

The source of heat and light energy produced by stars is:

The main characteristics used to classify stars include all of the following EXCEPT:

The color of the hottest stars is:

Although the Sun may look bright and white when you quickly look at it, the Sun is classified by color as:

By size, the star known as our Sun is classified as:

Scientists measure distances beyond our solar system (such as the distance between two stars) using these units:

For continuous fusion of hydrogen to take place, extreme conditions must exist in a star. These conditions include all of the following EXCEPT:

According to the H-R diagram in Figure 16-1A, the areas labeled B and E would be classified as:

According to the H-R diagram in Figure 16-1A, the areas labeled C and D would be classified as:

As a group, stars known as main sequence stars on an H-R diagram are best described as being:

Two stars have the same luminosity. The first star is one light year away from your telescope. The second star is four light years away from your telescope. The first star’s brightness is:

The brightness of the Sun when measured from various planets in the solar system would be:

Sirius is about 8.8 light years from Earth. If one light year equals 9.46 ´ 10¹² kilometers, how far is Sirius from Earth, measured in kilometers?

The distance from Earth to the star Proxima Centauri is 4.01 ´ 10¹³ kilometers. What is this distance in light years? One light year is equal to 9.46 ´ 10¹² kilometers.

If you were traveling at 30 kilometers per second, how long would it take to reach Proxima Centauri, the nearest star to Earth other than our Sun? Proxima Centauri is 4.01 ´ 10¹³ kilometers from Earth. Hint: there are 31,557,600 seconds in one year.

Small, dark areas on the surface of the sun where the temperature is lower than the surrounding surface area are known as ____________________.

The source of the sun’s energy output is the process known as nuclear ____________________.

Conditions needed for the continuous fusion of hydrogen in stars include extremely high mass, high density, and high _________________________.

The hottest stars in the universe are colored ____________________.

The smallest stars, those with a diameter of 20 to 30 kilometers, are called ____________________ stars.

The fusion of hydrogen in stars releases ____________________ and creates the element helium.

List the four main characteristics used to classify stars.

Use the H-R diagram below to answer the following questions:



Figure 16-1A

Which group of stars on the H-R diagram in Figure 16-1A is in the most stable part of the star “life cycle”?

On the H-R diagram in Figure 16-1A, which sections indicates white dwarfs? Describe one significant difference between a typical white dwarf star and a typical red giant star.

Name the two by-products of the fusion of hydrogen nuclei that takes place at the core of stars.

The distance from Earth to the star Betelgeuse is 6.62 ´ 10¹⁵ kilometers. If one light year is equal to 9.46 ´ 10¹² kilometers, what is the distance from Earth to Betelgeuse in light years?

The distance from Earth to the Triangulum galaxy is 2.6 million (2.6 ´ 10⁶) light years. If one light year is equal to 9.46 ´ 10¹² kilometers, what is the distance between Earth and the Triangulum galaxy in kilometers?

Two stars have the same luminosity. The first star is located 5 light years from Earth. The second is 10 light years from Earth. Compare the brightness of the two stars as seen from Earth.

Explain the difference between the brightness and luminosity of stars.

What is an H-R diagram and why is it important to astronomers?