Review - The Stars

When an astronomer rambles on and on about the luminosity of a star she is studying, she is talking about:

• what color the star is

• the total amount of mass in the star

• the star's apparent size (the size seen from Earth)

• how much energy the star gives off each second

Using a good pair of binoculars, you observe a section of the sky where there are stars of many different apparent brightnesses. You find one star that appears especially dim. This star looks dim because it is:

• very far away

• very low luminosity

• radiating most of its energy in the infrared region of the spectrum

• it could be more than one of the above; there is no way to tell which answer is right by just looking at the star

Which of the following looks the brightest in the sky?

• a star with magnitude 10

• a star with magnitude 6

• a star with magnitude -1

• you can't fool me, all of the above look equally bright from Earth

Which color star is likely to be the hottest?

• red

• blue-violet

• yellow

• orange

Most of the stars we can see with the unaided eye from Earth are

• very close to us (among the closest stars)

• more luminous (intrinsically brighter) than the Sun

• only visible to our eyes because they actually consist of three or more stars blending their light together

• undergoing some sort of explosion which makes their outer layers unusually bright

An H-R Diagram plots the luminosity of stars against their:

• mass

• diameter

• surface temperature

• age

Who was the astronomer who is the "H" in H-R diagram?

• Hubble

• Hertzsprung

• Huggins

• Hoyle

Ninety percent of all stars (if plotted on an H-R diagram) would fall into a region astronomers call:

• the supergiant region

• the main sequence

• the white dwarf region

• the visual region

Astronomers identify the main sequence on the H-R diagram with what activity in the course of a star's life?

• fusing hydrogen into helium in their cores

• letting go of a huge outer layer

• dying

• you can't fool me; so many stars are on the main sequence that there is no special stage in a star's life that can be identified with it

Tags

NGSS.HS-ESS1-1

Astronomers call a ball of matter that is contracting to become a star

• a giant molecular cloud

• a planet

• a protostar

• a main sequence star