Astronomers 'excited' by supernova

2011-08-29 16:12

Duncan Alfreds

Cape Town - Astronomers have discovered a supernova that may help to test current theories of the universe.

Last spotted in 1972, a Type 1a supernova has been observed in the galaxy M101, about 21 million light years from Earth.

"We are very excited to get one this close," said Oxford University astronomer and Palomar Transient Factory (PTF) collaborator Mark Sullivan.

"We essentially discovered it the day it blew up."

Data from the supernova would be used to check on current theories of universe expansion and dark energy models.

Excited

"If you know what the expansion rate of the universe is, your theory would then predict how bright a supernova would appear at a certain red shift away from us," Dr Enrico Olivier of the South African Astronomical Observatory told News24.

"What has been found out is that supernovae [Type 1a] actually appear to be further away than what you'd expect in a 'normal' universe where the acceleration is slowly decreasing," he added.

Astronomers were particularly excited by the supernova because it presents an opportunity to study an object more closely than has been the case in the past.

"We know it's the youngest Type 1a ever observed," said Peter Nugent of Lawrence Berkeley National Laboratory in California, who leads the Type 1a search group with PTF.

"This thing just shot up out of nowhere."

Type 1a supernovae are formed when white dwarf stars are pushed over a theoretical mass limit and are useful to astronomers because it allows them to measure distance.

Peak

"The assumption is that they all have nearly the same brightness and so we can therefore use them as distance indicators by seeing how bright they appear," said Olivier.

Observations of Type 1a supernovae in remote galaxies led to the revelation in 1998 that the expansion of the universe is speeding up over time due to the presence of dark energy, a poorly understood phenomenon.

The supernova will peak in early September and casual observers in the northern hemisphere should be able to see it with small telescopes under dark skies.


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