Exploding star discovered in nearby galaxy

Astronomers working on the Palomar Transient Factory (PTF) survey, have discovered a new supernova exploding in the nearby spiral galaxy, M101.
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At a distance of only about 21 million light years, this explosion is one of the closest of its type to happen in our lifetimes and astronomers across the world are turning their telescopes to point at this exciting new object.
 
One of the leaders of the team that discovered the supernova was Andy Howell, staff scientist at LCOGT and adjunct professor of physics at University of California, Santa Barbara (UCSB). He said, "We caught this supernova earlier than we've ever discovered a supernova of this type. On Tuesday, it wasn't there. Then, on Wednesday, boom! There it was –– caught within hours of the explosion. As soon as I saw the discovery image I knew we were onto something big."

The PTF survey's aim is to find and study astronomical events, such as supernovae explosions, as they happen. Their automated telescopes scan the skies, looking for exciting occurrences such as this one and once they find suitable candidates, they then alert astronomers at other telescope sites to carry out follow-up observations.

Here you can see before (left) and after (right) images of the supernova in the galaxy, taken by the Palomar 48-inch telescope (Credit: Peter Nugent and the Palomar Transient Factory).

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A supernova such as the one discovered by Howell and his team, is the endpoint in the life of a star with a mass greater than 15 times the mass of the Sun. Nuclear fusion stops in the core of the star, which then collapses and bounces back outwards, ejecting most of its matter into space. During this explosion, the star increases drastically in luminosity, which is the visible supernova. The matter which was blown out from the star heats up as it travels through the gas and dust in space, causing it to glow. This is known as a supernova remnant.

Depending on the mass of the star, it either collapses to form a neutron star or, in the case of stars more than a hundred times the mass of the Sun, it forms a black hole. After the explosion, the star’s luminosity gradually decreases. A plot of how the luminosity of the star changes with time as all this happens, is called a light curve, and astronomers studying these curves can use the data to measure the expansion of the Universe.

For more information on this newly discovered supernova, have a look at the UCSB's website here.

If you'd like to use data from the Faulkes Telescopes to plot your own lightcurve for a supernova like the one discovered on Wednesday, try the activity here on the Faulkes Telescope Project's resources site.

Finally, for more information on the life cycle of a star, check out the 'Stars' section of the resources site.