Question 1

Supernovae are of particular importance in theories of stellar evolution because:

Accepted Answer

Supernovae are known for producing the heaviest elements through nucleosynthesis. This is a crucial process for the evolution of stars and the formation of galaxies.

Question 2

The next element in the periodic table after tin (chemical symbol Sn) is antimony (chemical symbol Sb). If ¹²²Sn captures a neutron, the result will be:

Accepted Answer

When tin (Sn) captures a neutron, its neutron count increases by one, but its proton count (and thus its atomic number) remains the same, resulting in a heavier isotope of tin, not a change to antimony (Sb).

Question 3

Supergiants are huge stars of 25 or 30 M ? , which are undergoing core nuclear fusion involving nuclei heavier than carbon. These supergiants:

Accepted Answer

Supergiants may be any of a variety of colors depending on their surface temperature, which can range from about 3,000 Kelvin to over 30,000 Kelvin. Cooler supergiants will appear red or orange, while hotter supergiants will appear blue or white.

Question 4

The star that exploded to form the supernova SN 1987A probably had, before it blew up, a mass of:

Accepted Answer

The star that exploded to form SN 1987A is estimated to have had a mass of about 20 times that of the Sun (20 M☉) before it exploded. This is based on observations and models of the supernova and its progenitor.

Question 5

A blue (hot) supergiant is 10 times larger in diameter than the Sun, but a red (cool) supergiant of the same luminosity has a diameter 1000 times that of the Sun. How does the surface temperature of the blue supergiant compare to that of the red supergiant?

Accepted Answer

The answer of A blue (hot) supergiant is 10 times...

Question 6

The progenitor of SN 1987A was a smaller blue supergiant rather than a larger red supergiant when the core erupted as a supernova. What difference did this make?

Accepted Answer

The more compact state of a blue supergiant means that more energy is required to overcome the gravitational pull of the dense core when the star explodes. This results in less energy being available to contribute to the luminosity of the supernova, making it less bright than it might have been if the progenitor were a less dense, larger red supergiant.

Question 7

In 1990, the HST first examined SN 1987A and found a ring of glowing gas surrounding it. In 1994, HST found three rings of glowing gas. What happened during this interval?

Accepted Answer

The optics on the Hubble Space Telescope (HST) were repaired in 1993, significantly improving its resolution. This allowed astronomers to observe details that were previously not visible, such as the two additional rings around SN 1987A.

Question 8

What was the effective "neutrino energy luminosity" (energy carried away by neutrinos) of the SN 1987A supernova for a few seconds following the explosion compared to relatively well-known electromagnetic luminosities?

Accepted Answer

The answer of What was the effective "neutrino energy luminosity"...

Question 9

Scientists were able to calculate the number of neutrinos released by SN 1987A over a 10-s period from the number ascertained at the detectors. In order to make this calculation, it was necessary to know the distance to the supernova and which one of the following pieces of information?

Accepted Answer

To calculate the total number of neutrinos released by SN 1987A from the number detected, scientists needed to know the efficiency of the neutrino detectors. This efficiency indicates how many of the neutrinos passing through the detector are actually detected, which is crucial for estimating the total number released by the supernova based on the detected amount.

Question 10

If SN 1987A produces 10⁵⁷ neutrinos per second (uniformly in all directions), and it is at a distance of 51,500 pc (=1.59 × 10²¹ m), what would be the flux of neutrinos at an Earth-based detector with an area of 1 square meter?

Accepted Answer

The flux of neutrinos, $F$, at a distance $d$ from a source emitting $N$ neutrinos per second isotropically is given by $F = \frac{N}{4\pi d^2}$. Substituting $N = 10^{57}$ neutrinos per second and $d = 1.59 \times 10^{21}$ meters, the flux at Earth is calculated as $F = \frac{10^{57}}{4\pi (1.59 \times 10^{21})^2}$ meters$^{-2}$s$^{-1}$, which simplifies to approximately $3.15 \times 10^{13}$ neutrinos m$^{-2}$s$^{-1}$, matching choice A.

Question 11

Neutrino detectors for astronomical purposes are built and operated deep underground to:

Accepted Answer

Neutrino detectors for astronomical purposes are built and operated deep underground to shield them against other high-energy radiation from space or from natural radioactivity.

Question 12

What is Cherenkov radiation?

Accepted Answer

Cherenkov radiation occurs when a charged particle, such as a positron, moves through a dielectric medium (like water) at a speed greater than the speed of light in that medium. This results in a kind of electromagnetic shock wave, which manifests as a blue glow. This phenomenon does not imply that particles exceed the speed of light in a vacuum, which would violate the principles of relativity, but rather that they exceed the phase velocity of light in that specific medium.

Question 13

A Type Ib supernova is believed to result from the:

Accepted Answer

Type Ib supernovae are believed to result from the explosion of a massive star that has lost its hydrogen-rich outer layers through a stellar wind or by mass transfer in a binary star system. This leaves behind a core made mostly of helium and heavier elements, which can undergo further fusion reactions and eventually collapse to form a supernova.

Question 14

A supernova is observed with no emission or absorption lines of hydrogen, helium, or silicon. What type of supernova is it?

Accepted Answer

The absence of hydrogen, helium, or silicon lines indicates that the outer layers of the star have been stripped away, which is a characteristic of Type Ic supernova. Type Ia, Ib and II supernova, on the other hand, typically show hydrogen or helium lines in their spectra.

Question 15

A supernova of Type Ia has a much higher peak luminosity than a supernova of Type II. When we measure luminosity, we are including the energy of all of the following EXCEPT:

Accepted Answer

Neutrinos have a very low interaction cross section and are not typically included when measuring luminosity of astronomical objects. The other options (ultraviolet radiation, gamma rays, and X-rays) are all forms of electromagnetic radiation and are included in luminosity measurements.

Question 16

Measurements from distant galaxies indicate that supernovae should occur at a rate of two per century in a spiral galaxy such as the Milky Way, but only three have been recorded in our galaxy in the past 1000 years. Why is this?

Accepted Answer

The dense gas and dust in the plane of the Milky Way can obscure the light from supernovae, making them difficult to observe from Earth.

Question 17

More supernovae have been recorded, on average, in distant galaxies than in the Milky Way Galaxy. Why is this?

Accepted Answer

We view other galaxies from a variety of orientations, not just along the central plane of the Milky Way, where dust obscures our view of its supernovae. This makes it easier to detect supernovae in distant galaxies compared to our own.

Question 18

Supernova remnants are LEAST likely to be discovered when observers are attempting to detect them by looking for:

Accepted Answer

Neutrinos are extremely difficult to detect and rarely interact with matter, making them a challenging method for detecting supernova remnants. However, radio waves, x rays, and visible light are commonly used to detect supernova remnants.

Quiz 20: Stellar Evolution: The Death of Stars

Supernovae are of particular importance in theories of stellar evolution because:

The next element in the periodic table after tin (chemical symbol Sn) is antimony (chemical symbol Sb) . If ¹²²Sn captures a neutron, the result will be:

Supergiants are huge stars of 25 or 30 M ? , which are undergoing core nuclear fusion involving nuclei heavier than carbon. These supergiants:

The star that exploded to form the supernova SN 1987A probably had, before it blew up, a mass of:

A blue (hot) supergiant is 10 times larger in diameter than the Sun, but a red (cool) supergiant of the same luminosity has a diameter 1000 times that of the Sun. How does the surface temperature of the blue supergiant compare to that of the red supergiant?

The progenitor of SN 1987A was a smaller blue supergiant rather than a larger red supergiant when the core erupted as a supernova. What difference did this make?

In 1990, the HST first examined SN 1987A and found a ring of glowing gas surrounding it. In 1994, HST found three rings of glowing gas. What happened during this interval?

What was the effective "neutrino energy luminosity" (energy carried away by neutrinos) of the SN 1987A supernova for a few seconds following the explosion compared to relatively well-known electromagnetic luminosities?

Scientists were able to calculate the number of neutrinos released by SN 1987A over a 10-s period from the number ascertained at the detectors. In order to make this calculation, it was necessary to know the distance to the supernova and which one of the following pieces of information?

If SN 1987A produces 10⁵⁷ neutrinos per second (uniformly in all directions) , and it is at a distance of 51,500 pc (=1.59 × 10²¹ m) , what would be the flux of neutrinos at an Earth-based detector with an area of 1 square meter?

Neutrino detectors for astronomical purposes are built and operated deep underground to:

What is Cherenkov radiation?

A Type Ib supernova is believed to result from the:

A supernova is observed with no emission or absorption lines of hydrogen, helium, or silicon. What type of supernova is it?

A supernova of Type Ia has a much higher peak luminosity than a supernova of Type II. When we measure luminosity, we are including the energy of all of the following EXCEPT:

Measurements from distant galaxies indicate that supernovae should occur at a rate of two per century in a spiral galaxy such as the Milky Way, but only three have been recorded in our galaxy in the past 1000 years. Why is this?

More supernovae have been recorded, on average, in distant galaxies than in the Milky Way Galaxy. Why is this?

Supernova remnants are LEAST likely to be discovered when observers are attempting to detect them by looking for:

Quiz 20: Stellar Evolution: The Death of Stars

Supernovae are of particular importance in theories of stellar evolution because:

The next element in the periodic table after tin (chemical symbol Sn) is antimony (chemical symbol Sb) . If 122Sn captures a neutron, the result will be:

Supergiants are huge stars of 25 or 30 M ? , which are undergoing core nuclear fusion involving nuclei heavier than carbon. These supergiants:

The star that exploded to form the supernova SN 1987A probably had, before it blew up, a mass of:

A blue (hot) supergiant is 10 times larger in diameter than the Sun, but a red (cool) supergiant of the same luminosity has a diameter 1000 times that of the Sun. How does the surface temperature of the blue supergiant compare to that of the red supergiant?

The progenitor of SN 1987A was a smaller blue supergiant rather than a larger red supergiant when the core erupted as a supernova. What difference did this make?

In 1990, the HST first examined SN 1987A and found a ring of glowing gas surrounding it. In 1994, HST found three rings of glowing gas. What happened during this interval?

What was the effective "neutrino energy luminosity" (energy carried away by neutrinos) of the SN 1987A supernova for a few seconds following the explosion compared to relatively well-known electromagnetic luminosities?

Scientists were able to calculate the number of neutrinos released by SN 1987A over a 10-s period from the number ascertained at the detectors. In order to make this calculation, it was necessary to know the distance to the supernova and which one of the following pieces of information?

If SN 1987A produces 1057 neutrinos per second (uniformly in all directions) , and it is at a distance of 51,500 pc (=1.59 × 1021 m) , what would be the flux of neutrinos at an Earth-based detector with an area of 1 square meter?

Neutrino detectors for astronomical purposes are built and operated deep underground to:

What is Cherenkov radiation?

A Type Ib supernova is believed to result from the:

A supernova is observed with no emission or absorption lines of hydrogen, helium, or silicon. What type of supernova is it?

A supernova of Type Ia has a much higher peak luminosity than a supernova of Type II. When we measure luminosity, we are including the energy of all of the following EXCEPT:

Measurements from distant galaxies indicate that supernovae should occur at a rate of two per century in a spiral galaxy such as the Milky Way, but only three have been recorded in our galaxy in the past 1000 years. Why is this?

More supernovae have been recorded, on average, in distant galaxies than in the Milky Way Galaxy. Why is this?

Supernova remnants are LEAST likely to be discovered when observers are attempting to detect them by looking for:

The next element in the periodic table after tin (chemical symbol Sn) is antimony (chemical symbol Sb) . If ¹²²Sn captures a neutron, the result will be:

If SN 1987A produces 10⁵⁷ neutrinos per second (uniformly in all directions) , and it is at a distance of 51,500 pc (=1.59 × 10²¹ m) , what would be the flux of neutrinos at an Earth-based detector with an area of 1 square meter?