Name : Matthew Wolfe
Student Number :
Subject : AST131-F
Semester : First
Assignement 4

1)A neutron star is the remainder of a giant or super giant once it has shed enough mass (either resulting from a nova or from the gradual solar wind) to collapse under its own weight (between 1.4 and 3 SM), the resulting object is a superdense sea of protons and electrons which combine to form degerate neutrons. The pressure of the super dense neutron gas supports the star and the sudden decrease in size and increase in pressure and temperature give it a very fast spin.

On the other hand if a collapsing star core has a mass of more than 3 SM the degenerate neutrons formed can not stop the pressure from compressing them even further and it contracts into an infitely small size (a zero radius), at this point the gravity would be strong enough for it to everything, including photons from leaving it. The main differences are that the neutron star manages to stop further compression, the black hole can not. They share a lot of characterisitics such as X-Ray emission from absorbing nearby objects, being "compact objects". While neutron stars are very hard to detect, black holes are much harder due to their characterisitcs of no light coming from them and their tiny size, the only way to detect them is through their interactions with the environment.

2a) Drawing :

2b)
Population 1 Stars - Disk
Population 2 Stars - Halo and towards the nuclear bulge                                 
Gas and Dust - Disk
Open Clusters - Disk
Globular Clusters - Halo

2c)
The Sun is a population 1 star, this is due to the fact that the stars of the disk are stars that will contain a much higher yield of metal than the stars of the other parts. We also know that the sun is  not very old, so it has been made from a metal-enriched ISM, although we are closer to an intermediate population 1 star.

3a)
Elliptical, Spiral, Irregular

b)
Elliptical Galaxies contain very little gas, dust and other constituents of IMS as such the stars are generally more massive and give the galaxy a redish tint. They also have the ability to have extremely high masses

Spiral Galaxies support star formation and as such have plenty of the basic compounds for star birthdue to this, the majority of the stars are oung or small and as such give the galaxy a blue/green tint albiet highly luminous.

Irregular Galaxies are obviously galaxies that do not fall into the other two types. However they do support star formation and contain dust and gas and are generally pretty small in size.

c)
Our galaxy is a barred-Spiral galaxy.