A Supernova is one of the ways a star can die. It can't hold itself up any longer and collapses creating a huge nuclear reaction. The star can burn 100 billion times more brightly than it had just before the collapse, and since there are typically 100 billion stars in a galaxy, this single star can give off more light than the entire galaxy it resides in! They can burn like this for a month or so. They really stand out.
Nowadays, hundreds of Supernovae are discovered each year by astronomers. This page discusses two particular Supernovae discovered one night in April 2007. Both were located in the constellation Leo. The Annals of Science have recorded their discoveries by a certain astronomer, HOWEVER, WE CAN NOW REVEAL that Angela Runge was actually the first human to detect these Supernovae!!! This was done by "cherry-picking" the night's data before the astronomers got to it. The ethics of this scientific behavior aside, we now describe these two Supernovae.
The left-hand image above is a region of the sky before April 24, 2007. The blob of light in the green box is a galaxy.
The right-hand image above is the region of the sky on the night of April 24, 2007. In the center of the green box we see a new object. That object turned out to a Supernova. Chalk one up for Angela.
The left-hand image above is another region of the sky before April 24, 2007. The blob of light in the green box is a galaxy.
The right-hand image above is the region of the sky on the night of April 24, 2007. In the center of the green box we see a new object. That object turned out to a Supernova. Chalk another one up for Angela.
The latter one turned out to be a special type of Supernova known as a 'Type Ia'. Because of this, it was followed and studied in more detail. It was determined that this Supernova is 892 million light-years away. That means the explosion went off about 892 million years ago. Dinosaurs came into being and became extinct while this light was travelling to us.
Many spectra of this Supernova were taken. Here is one spectrum
taken in May 2007:
The dip in the blue curve at around 0.66 (wavelength 6600 Angstroms) is due to absorption by ionized Silicon. This is a 'marker' for Type Ia Supernovae.
Since Type Ia are very consistent in their brightness, they can be used as 'standard candles' to measure the distance to the galaxy where the Supernova took place. Measuring distances might not seem terribly exciting, but this method has been used to show that the expansion of universe is accelerating (rather than decelerating as once thought.) This is currently one of the greatest unsolved puzzles in science. Angela's Type Ia Supernova provides one data point in solving the puzzle.