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| The Cigar Galaxy or M82 in the constellation Ursa Major. Bradford Robotic Telescope 2015 - Galaxy Camera - BVR filters. |
The Cigar Galaxy is a starburst galaxy, an active galaxy where many new stars are being created from the gravitational collapse of cold molecular hydrogen clouds. The Cigar is between 11.4 and 12.4 million light years distant in the constellation of the Great Bear, Ursa Major. It is a spiral galaxy which from Earth we view almost edge on.
The galaxy has a diameter of 37,000 light years and is five times more luminous than our home galaxy the Milky Way.
In March 2014 I imaged a supernova in the Cigar Galaxy using my Meade 127mm. refractor. As the image was unguided the stars are a bit blobby but you can see the bright dot that was the massive explosion to the lower right of the galaxy disc. By the time I used the Bradford Robotic Telescope to image the Cigar in the latter part of 2015 the light from the aftermath of the explosion had faded away.
Starburst Galaxies are great places to look for supernova. Where there is a high level of star birth there is often a high probability of finding supernovae.
Single massive stars, when they use all their hydrogen and helium reserves, become unstable. Outward pressure created by the fusion of hydrogen and then helium in the star's core, reduces and eventually gravity overwhelms the star. The core collapses and is blown apart in a type 2 Supernova leaving behind a neutron star or a black hole.
The majority of stars are not massive or alone. Many stars are in binary or multiple star systems and age more gracefully at a rate inversely commensurate with their mass. The larger star in a binary system will enter its old age first and become bloated and red as it fuses the last of its helium reserves. Finally the star will shed all of its outer layers in the form of a planetary nebula leaving the very hot and small core of the star as a 'White Dwarf''
Follow links:
Planetary Nebula
Type 2 Supernova
Type 1a Supernova
In a binary star system containing a white dwarf and an ageing bloated red star, mass from the red giant can transfer to the white dwarf. When sufficient mass has transferred, the Chandrasekhar Limit (1.44 solar masses), the white dwarf explodes in a nova or type 1a supernova. In a Supernova this results in the complete destruction of the white dwarf star but in a nova the white dwarf survives and the process of mass transfer recommences.
There are many examples of repeating nova in binary sytems.
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| My image from March 2014 | | | | | | |
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| Image of the Nova in the constellation Delphinius taken from our Backyard using the 127mm. Meade refractor. |
Funny that when you look out into space, apart from the sun, the moon and the planets, it always looks about the same, but in reality stars are created and destroyed in a shared process of birth, life and death, no different from our existence. Our lives are measured in a few tens of years, our species in a few million and the stars from tens of millions to billions. In the end however, for both the Universe and us 'entropy' will have its way!
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| By NASA, ESA, and The Hubble Heritage Team (STScI/AURA) - http://www.spacetelescope.org/images/html/heic0604a.html (direct link)http://hubblesite.org/gallery/album/entire_collection/pr2006014a/, Public Domain, https://commons.wikimedia.org/w/index.php?curid=797295 |
Credits: NASA< ESA, Bradford Robotic Telescope and Wikipedia
