Pulsars

The pulsar is a topic I have often heard about and was always curious about the major facts of their existence. Most documentaries I've watched have covered some of the main concepts of pulsars: rotating neutron stars that have cones of radiation emitting from it's magnetic poles. However I haven't really dug deeper into the other observations made about them. Are there more than one type of pulsar/ neutron star? What exactly classifies a neutron star? Are there any in our galaxy? What would happen to objects near it?
So let's dive in then and look some of this up.
Starting from the beginning of the topic, the neutron star. A neutron star is an extremely dense, usually very small (average so far is about 20 km diameter), core of a star left over from a supernova. It's remnants are the matter that was unable to escape the intense gravity at the core during the supernova (usually around 2-3 solar masses). This matter collapses down so much that protons and electrons combine to for neutrons. Neutron star, makes sense. Since a neutron star has such a small radius comparatively to it's former star self, the rotational speed of the neutron star is extremely high. The concept of a neutron star was proposed in 1934 and was confirmed in 1967 through the discovery of a pulsar. They emit electromagnetic  radiation and they usually appear white in the visible spectrum since they generally emit photons across the spectrum.
Most of the neutron stars discovered have been in the form of a pulsar which is a rotating, highly magnetized version of a neutron star. The rotation is determined by the cone of radiation crossing the path of the earth. We can use it's blinking of the cones from the poles to see the rotational period of the pulsar. Usually many pulsars spin extremely fast upon creation but gradually lose their energy and begin to slow down. The average speed of a pulsar we can observe today range from one second to 30 seconds. However there are others that are much faster than this still. The crab nebula has a pulsar at it's center that has a rotational period of about 30 rotations a second. This pulsar is one of the more famous ones since it is the result of one of the few witnessed supernovas by mankind; it happened in 1054 AD and was observed by Chinese and European astronomers during the day!

http://www.jb.man.ac.uk/pulsar/Education/Sounds/crab.au

The Crab Nebula picture (Optical and X-ray composite) and a link to the sounds representing the radio-waves detected from the pulsar.


There are multiple categories of pulsars relating to the way in which they power their electromagnetic emissions.
Rotation powered pulsars are pulsars that transform rotational energy into electromagnetic emissions and lose energy in the system this way.
Accretion powered pulsars are pulsars that are usually in a binary system with another star and fuel the emissions through matter taken from the neighboring star and merging it with it's own mass. Pulsars that are this type usually emit in the X-ray portion of the spectrum.
Magnetars are the third type which gain the power for emission through the decay of it's own intense magnetic field. Magnetars are usually the shortest lived of pulsars, halting it's emissions over the course of around 10,000 years.
Since pulsars slow their rotation gradually overtime, not allowing the electromagnetic radiation to pass by earth, they become "dormant" as we can no longer observe them. The time it takes for this to happen is usually 10-100million years after it's creation. Over the time of the Universe's existence, it is believed that 99% of all pulsars are now dormant.
 Pulsars are generally located in most areas of space including our own galaxy. Currently we know of 2000 neutron stars in our galaxy alone. The closest one to us is 130 parsecs away.
Interaction with a neutron star can be quite devastating. In Binary systems, they are known to eventually steal mass from it's partner star and use that to fuel it's emissions. If the second star is large enough and becomes a neutron star itself, if they remain in orbit together, it is theorized that the two neutron stars can eventually collide and form a black hole.
There have been cases of planets being discovered around pulsars as well. One such case, located in the Milky Way, theorizes that the planet orbiting the pulsar is now a crystalline carbon planet, a diamond planet. The theories push that the planet was originally a star in a binary system with the pulsar. When the star moved into a closer orbit with the pulsar, the pulsar began stealing it's mass until it took away 99.9% of its mass leaving it a cold fusion-less planet known as a white dwarf. Measurements indicate that it's density is high enough that the mostly carbon composition of the planet is most likely in a crystalline state. According to the article, this planet is an object that helps challenge the definitions of what is a star and what is a planet.

Artistic rendition of the pulsar with the orbiting white dwarf. The rotational period of the star is about 10,000 revolutions per minute and the white dwarf orbits around the pulsar once every 2 hours and 10 minutes.

As for other planets orbiting the pulsar before it became one, they would need to survive the supernova that creates the pulsar to remain part of the system afterwards. In most cases, regular rocky and gaseous planets would be blasted away by a supernova and would not remain.
One thing I had trouble finding was the effects of the x-ray and other electromagnetic emissions on other bodies such as planets and stars or even other systems. I figure they would be extremely detrimental towards life, but for the stability of other star systems, if they were close enough, would the constant bursts be enough to destabilize orbits?


Sources:
http://www.cosmosmagazine.com/news/planet-made-diamond-found-milky-way/
http://www.astrophysicsspectator.com/topics/milkyway/RadioPulsarDistribution.html
http://imagine.gsfc.nasa.gov/docs/science/know_l2/pulsars.html
http://imagine.gsfc.nasa.gov/docs/science/know_l1/pulsars.html
http://en.wikipedia.org/wiki/Pulsar
http://en.wikipedia.org/wiki/Neutron_star
http://www.jb.man.ac.uk/pulsar/Education/Sounds/sounds.html