Chapter 19, 22, 23

Which of the following statements about a Type II Supernova is true?

A Type II supernova occurs at the end of the life of a star with 10 times the mass of our Sun or more

matching

DBAGEHFC

MATCHING

DEACB

MATCHING

FCDEAB

The period-luminosity relationship for Cepheid variables was discovered by

Henrietta Leavitt

Which of the following types of stars will spend the longest time (the greatest number of years) on the main sequence?

K

What is the closest star to the Sun?

Proxima Centauri

The astrophysicist who first calculated the highest mass that a dying star can have and still be a white dwarf was

S. Chandrasekhar

Which of the following statements about the mass of the Sun during its lifetime is correct?

The Sun will lose a significant amount of mass during and after its red giant phase

Although centuries ago, astronomers thought that a nova was a new star, appearing for the first time in the heavens, today we know that it is:

a binary star system in which one star is a white dwarf and mass is being transferred to it

A type of star cluster that contains mostly very old stars is

a globular star cluster

When the mass of a star's core is greater than 1.4 times the mass of the Sun, degenerate electrons can t keep it stable as a white dwarf. Instead, it becomes:

a neutron star

The event in the life of a star that begins its expansion into a giant is

almost all the hydrogen in its core that was hot enough for fusion has been turned into helium

Why did it take astronomers until 1838 to measure the parallax of the stars?

because the stars are so far away that their annual shift of position in the sky is too small to see without an excellent telescope and careful observer

Why can a star with a mass like our Sun not fuse (produce) further elements beyond carbon and oxygen?

because they just cannot get hot/close enough for the fusion of heavier nuclei because it lacks mass and stronger gravity

How did Henrietta Leavitt calibrate her period-luminosity relationship for Cepheid variable stars? In other words, how did she make the general idea into a numerical rule?

by noting that the period was related to the luminosity in all stars (WRONG)

After the core of a massive star becomes a neutron star, the rest of the star's material

explodes outward as a supernova

If an astronomer wants to find the distance to a star that is not variable and is located too far away for parallax measurements, she can:

find the star's luminosity class from its spectrum and read the luminosity from an H-R diagram

The oldest structures in our Galaxy turn out to be

globular clusters

If mid-sized stars with masses like our Sun s cannot make elements heavier than oxygen, where are heavier elements like silicon produced in the universe?

heavier elements are made in the cores of significantly more massive stars than the Sun, which can get hotter in their core and have greater gravity

In a collapsing star of high mass, when electrons and protons are squeezed together with enormous force, they turn into a neutron and a:

highly energetic neutrino

The most stable (tightly bound) atomic nucleus in the universe is:

iron

How long a main sequence star remains on the main sequence in the H-R diagram depends most strongly on

its initial mass

How are globular clusters distributed in our Milky Way Galaxy?

mostly in a large halo aove and below the flat disk of the Galaxy

Kepler's Laws can give us the relative distance of objects in the solar system. To convert these relative distances into actual distances, we needed to:

not exactly sure, i guessed C

If most stars are low-mass stars, and low-mass stars typically eject a planetary nebula, why then do astronomers see relatively few planetary nebulae in the sky?

planetary nebulae expand and soon become too faint to be visible

A type of star that has turned out to be extremely useful for measuring distances is

the Cepheid variables

As a cluster of stars begins to age, which type of star in the cluster will move off the main sequence of the H-R diagram first?

the O and B type stars

An astronomical unit is:

the average distance between the Earth and the Sun

Which of the following is a characteristic of degenerate matter in a white dwarf star?

the electrons get as close to each other as possible and resist further compression

Why do Cepheid variables have that strange name?

the first such type of variable was discovered in a constellation called Cepheus

What incident in a massive star's life sets off (begins) the very quick chain of events that leads to a supernova explosion?

the fusion of iron

The measurement of cosmic distances was helped tremendously by the discovery, in the early part of the 20th century, that in Cepheid variable stars, the average luminosity was related to:

the period of time it takes to vary

What is the baseline that astronomers use to measure the parallax (the distance) of the nearest stars?

the radius of the Earth s orbit around the Sun

Many names used by astronomers are misleading or outdated. A good example is the term planetary nebula, which astronomers use to refer to:

the shell let go by a dying low-mass star

When a star undergoes a nova explosion, it may return to its quiet state and later become a nova again. What would allow a nova explosion to happen to a star more than once?

the star that goes nova has a companion star near it, which dumps material onto the first star and continues to do so even after the first nova explosion

In a Type Ia supernova, the cause of the violent outburst is:

the transfer of so much mass from a companion star that a white dwarf goes "over the limit" and collapses, causing an enormous amount of sudden fusion

Your sweetheart gives you a piece of gold jewelry as a present to celebrate your passing your astronomy class. Where did the gold atoms in that gift originally come from (where were they most likely made)?

they were built up from smaller nuclei during a supernova explosion

When the outer layers of a star like the Sun expand, and it becomes a giant, which way does it move on the H-R diagram?

toward the upper right

In a planetary nebula, the shell of expelled material is glowing intensely. What is the main source of energy for this glow?

ultraviolet radiation from the collapsing hot star at the center

When a single star with a mass equal to the Sun dies, it will become a

white dwarf

Which of the following stages can only occur in the life of a low-mass star (whose final mass is less than 1.4 times the mass of the Sun)?

white dwarf