Quiz 8.1 Stars

Which statement about an asterism is true?
1. An asterism is an astronomical phenomenon
2. The stars that make up an asterism exist in close physical proximity to each other
3. All the stars in an asterism must be approximately the same age
4. A constellation is a part of an asterism
This is an artist's conception of the birth of a star.

What is this formation called?
1. Protostar
2. Black hole
3. Red dwarf
4. Neutron star
This is an artist's conception of the birth of a star.

Why is this forming star spinning?
1. Matter falling inward toward the core has excess energy
2. Extremely high magnetism builds up inside the ball of matter
3. Material is being drawn in toward a black hole at the centre
4. The core is so hot that a nuclear reaction has begun
This kind of star is small and relatively cool. It is by far the most common kind of star in the universe. Following is an artist's conception of what this kind of star might look like close up.

What kind of star is this?
1. Red dwarf
2. Protostar
3. Red giant
4. Supergiant
What determines which kind of life cycle a protostar will experience?
1. Mass
2. Brightness
3. Rotational velocity
4. Composition
This is an artist's conception of a neutron star called PSR B1257+12. It is part of the constellation Virgo and is known to have three planets orbiting it.

A neutron star such as this one is the result of an exploding
1. supergiant star.
2. yellow main sequence star.
3. black hole.
4. white dwarf star.
What element, when formed in the core of a star, cannot release energy when it fuses and therefore is part of the last reaction cycle in that star before it explodes?
1. Iron
2. Hydrogen
3. Helium
4. Carbon
The Hertzsprung-Russell diagram categorizes stars based on three basic properties. What is not one of those properties?
1. Spectral red shift
2. Surface temperature
3. Colour
4. Luminosity
This is an artist's conception of a very low mass star called CHRX 73 A (also called Barnard's Star) and its companion object, CHRX 73 B, located about 6 light years away form Earth. CHRX 73 B is visible in the lower right part of this photograph.

Astronomers don't know if the companion (CHRX 73 B) is a huge planet (it is about 12 times more massive than Jupiter), a failed star or a brown dwarf. Whether life could exist around such a star as CHRX 73 A is up for debate. But they do know that CHRX 73 A is a very old star and will eventually grow dimmer and cool into a white dwarf. What type of star is CHRX 73 A?
1. Red dwarf
2. Red giant
3. Main sequence
4. Massive main sequence
This is the Hertzsprung-Russell diagram in which several known stars are plotted.

According to this diagram, which relationship between a star's luminosity, colour and temperature is most accurate?
1. Blue stars tend to be the most luminous and hottest stars
2. Yellow stars tend to have medium luminosities but they are extremely hot
3. All red stars are neither very luminous nor very hot stars
4. Main sequence stars all have very similar colours, luminosities and temperatures