Distinguish between properties of the two major types of supernovae: massive star supernovae and white dwarfs.

All supernovae represent the explosions of stars, but current understanding suggests there are two basic types of supernovae: one that occurs when a massive star reaches the end of its life, and the other that occurs when a white dwarf star explodes because its mass has exceeded the white dwarf limit (also called the Chandrasekhar limit) of 1.4 solar masses.

Match the items below with the correct type of supernova.

1. Star explodes completely, leaving no compact object behind.
2. Can only occur in a galaxy with ongoing star formation.
3. Black hole or neutron star left behind.
4. Can only occur in a binary system.
5. Can occur in a very old star cluster.
6. Spectra always lack strong hydrogen lines.
7. Has a brighter peak luminosity.

What I think...
White dwarf supernova:
1
4
5

Massive star supernovae:
2
3
6
7

But, I got it wrong. Can someone please help me? I don't know which ones are wrong.

A "white dwarf supernova" is also called Type I, and a "massive star supernova" is called Type II by astronomers.

Read about the latter at
http://en.wikipedia.org/wiki/Type_II_supernova

Description 6 applies to Type I, not Type II.

A agree with your other answers. If that still gets you marked wrong, do more reviewing of the properties of both types.

2, 3 supermassive

Your initial categorization was correct for some of the properties. However, there are a couple of mistakes. Here is the correct match for each property with the corresponding type of supernova:

1. Star explodes completely, leaving no compact object behind. (Massive star supernovae)
2. Can only occur in a galaxy with ongoing star formation. (Massive star supernovae)
3. Black hole or neutron star left behind. (Massive star supernovae)
4. Can only occur in a binary system. (Massive star supernovae)
5. Can occur in a very old star cluster. (Both types of supernovae can occur in very old star clusters)
6. Spectra always lack strong hydrogen lines. (White dwarf supernovae)
7. Has a brighter peak luminosity. (Massive star supernovae)

So, the corrections would be:

White dwarf supernova:
- 1 (Star explodes completely, leaving no compact object behind)

Massive star supernovae:
- 2 (Can only occur in a galaxy with ongoing star formation)
- 3 (Black hole or neutron star left behind)
- 4 (Can only occur in a binary system)
- 6 (Spectra always lack strong hydrogen lines)
- 7 (Has a brighter peak luminosity)

Overall, white dwarf supernovae typically leave no compact remnant, while massive star supernovae can leave behind black holes or neutron stars. Massive star supernovae can also occur in a wider range of environments, including galaxies with ongoing star formation.

Let's go through each item and determine the correct type of supernova for each:

1. Star explodes completely, leaving no compact object behind.
- This characteristic is associated with massive star supernovae. When a massive star reaches the end of its life, it undergoes a catastrophic collapse, resulting in a powerful explosion that destroys the star completely.

2. Can only occur in a galaxy with ongoing star formation.
- This characteristic is also associated with massive star supernovae. Massive stars are typically found in regions of active star formation, so the likelihood of a supernova occurring in such environments is higher.

3. Black hole or neutron star left behind.
- This characteristic is associated with massive star supernovae. After the explosion, the core of the massive star may collapse and form a black hole or a neutron star.

4. Can only occur in a binary system.
- This characteristic is associated with white dwarf supernovae. White dwarf supernovae occur in binary star systems where a white dwarf accretes matter from its companion star. When the mass of the white dwarf exceeds the Chandrasekhar limit, a thermonuclear explosion is triggered.

5. Can occur in a very old star cluster.
- This characteristic is associated with white dwarf supernovae. White dwarf supernovae can occur in both young and old star clusters, so this item does not provide definitive information on the type.

6. Spectra always lack strong hydrogen lines.
- This characteristic is associated with white dwarf supernovae. The explosion of a white dwarf does not involve hydrogen fusion, so the resulting spectra typically lack strong hydrogen lines.

7. Has a brighter peak luminosity.
- This characteristic is associated with white dwarf supernovae. White dwarf supernovae are generally brighter at their peak than massive star supernovae.

Using this information, we can now update your initial assumptions:

White dwarf supernova:
1
4
5
6
7

Massive star supernovae:
2
3

So, you had four correct answers and only one incorrect answer. Item 5 ("Can occur in a very old star cluster") was incorrectly assigned to massive star supernovae, whereas it is associated with white dwarf supernovae.