July 5, 2013
Astronomers Detect Relatively Cool Supernova Remnant
Lee Rannals for redOrbit.com - Your Universe Online
An international team of astronomers detected surprisingly low temperatures in the remnant of the supernova 1987A, helping to explain the mystery of why space is filled with dust grains and molecules.
The team used the Herschel Space Observatory and Atacama Millimeter and Submillimeter Array (ALMA) to study the supernova remnant. They were able to find a vast reservoir of unexpectedly cold molecules and dust.
"The powerful explosion we saw in 1987 scattered elements made by star into space in the form of a very hot plasma. The gas has now cooled down to temperatures between [-418 to -274 degrees Fahrenheit]. That's surprisingly cold, comparable to the icy surface of Pluto at the edge of our Solar System," said Dr. Mikako Matsuura, who presented the findings at the National Astronomy Meeting in St. Andrews. "The gas has formed molecules and some has even condensed into solid grains of dust. The supernova has now become a super freezer!"
The team's observations show the supernova produced dust and solid material equal to about 250,000 times the mass of the Earth, or three quarters of the mass of the Sun. Scientists have believed supernova remnants contain only very energetic atomic gas, but these new observations show this is not the case.
This discovery of a large mass of dust could help scientists understand how supernova slowly spread and fill galaxies with gas, dust and small rocky particles.
"We were surprised by the amount of dust and molecular gas in the reservoir created by the supernova 1987A. The ALMA and Herschel observations show that the reservoir contains carbon monoxide molecules equaling one tenth of the mass of the Sun. Herschel shows that the dust mass was even larger - about half the solar mass!" said Dr. Matsuura of the University of College London.
She said astronomers do not get many opportunities to study supernova. These events can be very rare and the majority of those found lie in very distant galaxies.
"Even with relatively close ones, like 1987A, it's difficult -- although they are very bright at the time of the explosion, the light from the supernovae fades very quickly making it very difficult to observe them a few years after the explosion," said Dr. Matsuura. "Carl Sagan once said that: 'We are all made of star-stuff'. These results will help us understand how that material reached us!"