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Crab Nebula (M1)
Mike Vriezema

Crab Nebula

The Crab is a very unique nebula.  Nebulae are typically supernovas that are still expelling materials at extremely fast velocities and temperatures, but what makes the Crab Nebula unique is that it is a supernova and a pulsar wind nebula as well.  A supernova is simply a star that reached the end of it’s life and, well, exploded.  We get the pulsar wind from one of the faint stars that is a spinning mass of neutrons that emits pulses of radiation.  The supernova half of the nebula comes from the progenitor star which was either a white dwarf or a massive star.  What is really interesting about the Crab is that scientists can’t seem to figure out why the nebula appears.  Normally masses of nebula must have at least 8 times the value of the sun otherwise it won’t be visible.  Scientists have deduced that the Crab must have had a value of somewhere between 9 and 11 times the solar mass, but their math disagrees with their assumption.  Based off of their calculations, the mass of the nebula must have been between 1 and 5M. Much about the Crab is unknown, but what we do know about the Crab nebula is that it has a radius of approximately 5.5 light years and is about 11 light years away from earth and is a part of the Taurus Constellation. It’s also been calculated that the temperature of the contents of the Crab is approximately 11000 Kelvin. With all of the unknowns, and the fact that the nebula is over 10 light years away, the Crab remains a mystery. 
As seen in the picture above, there is a very noticeable difference in colors.  There is a cloud of a yellowish tint, with a vibrant red accent throughout.  The Crab is made of mainly Helium ejecta moving at fast speeds with very high temperatures.  If you look towards the center of the nebula, you can see the brightest part of the Crab.  It is here where, under better magnification, we could more clearly see the two stars which are the sources of the Crab Nebula.

References:

 

Right Ascension (J2000) 05:35:12
Declination (J2000) +22:01:25
Filters used B (Blue), C (Clear), R (Red), V (Green)
Exposure time per filter B, V, C, and R (6s)
Date observed March 23, 2011, 21:52 EST

 

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