Astrophysics Basics

Put these objects in size order from the smallest.

• Comet

• Satellite

• Planet

• Star

• Galaxy

What is the reason a Main sequence star is so stable?

• The number of atoms remain the same

• The radiation pressure balances the pressure of weight

• Magnetic forces within it hold it together

• It has plenty of emotional support from it's friends

The brightness of a star depends on two factors. Which of the following shows the two factors?

• the luminosity of the star and its distance from the Earth

• the size of the star and its colour

• the luminosity of the star and its size

• the colour of the star and its surface temperature

Which of the following correctly identifies the absolute brightness of a star?

• the brightness of the star as seen from the Earth

• the amount of light emitted per second by the star

• the brightness of the star compared to other stars if all stars were the same distance from the Earth

• the colour of the star

A star’s brightness depends on its _________.

Its color depends on its ___________________.

Its life cycle depends on its __________.

• size, mass, color

• size, temperature, mass

• temperature, mass, size

All stars begin their life in a

• Main Sequence
• Nebula
• Protostar
• Black Dwarf

As the temperature of a star increases, the intensity of light from it

• may increase or decrease depending of the type of star

• increases

• decreases

• remains the same

The Milky Way is ​ (a)   ​ light years across and is ​ ​ (b)   light years thick towards the edge.

• 100 000
• 10 000
• 1 000
• 1 000 000

A star has a parallax angle of 0.02 seconds of arc. How far away is it in parsecs?

Which of the following characterizes a constellation

• stars are physically close together

• stars are gravitationally bound

• stars are not necessarily close together

• stars appear to be close together