v4641 Sagittarii

Black Holes

A black hole is a region of space that has so much mass concentrated in it that there is no way for a nearby object to escape its gravitational pull. There is no limit in principle to how much or how little mass a black hole can have. A typical mass for a  black hole would be about 10 times the mass of the Sun. They weigh about a million times as much as the Sun. You can't see a black hole directly so we have to rely on indirect evidence that black holes exist. This is the topic of my research paper.

Lets begin by explaining what a Quasar is. These objects are the very bright centers of some distant galaxies, where some sort of energetic action is occurring, most probably due to the presence of a super massive black hole at the center of that galaxy. The electrons near the center of the quasar can be accelerated to speeds near the speed of light. They emit radio waves. There are no nearby quasars. This is all relevant to my topic.

Now, we will touch on microquasars. A microquasar consists of a binary system in which a normal star orbits around, and loses matter to, a nearby compact object, either a black hole or a neutron star. A dozen or so microquasars have been found in the Milky Way Galaxy. Microquasars are a substantial source of high-energy particles and radiation in the Galaxy. The closest known microquasar and black hole to Earth is V4641 Sagittarii, which lies only about 1,500 light-years away. Now we are to the subject of my topic.

I chose v4641 Sagittarii as an example of a black hole. V4641 was discovered September 15, 1999 by Australian astronomer Ron Stubbings. V4641 Sgr underwent a very strong but very short outburst. Radio observations revealed relativistic jets associated with this outburst.  Is it roughly 3 to 10 times the mass of the Sun and a Diameter roughly 11-37 miles. V4641 Sgr is classified as a microquasar. It is in the constellation Sagittarius with a normal star named V4641 Sgr. It has orbital period of 2.8 days and at quiescence has an apparent magnitude of 13.8. It has a very turbulent magnetic field. That is all I could find about v4641 Sgr.