Image of Supernova 1987A taken by the Hubble Space Telescope and released by NASA in 2007 to celebrate the supernova's 20th anniversary.
Credit: NASA/ESA/CSA/R. O’Connell
SYDNEY: Detailed mapping of a famous supernova has brought the inner secrets of exploding stars to light, providing a first ever three-dimensional view of the erupted matter within, scientists said.
Supernova 1987A (SN 1987A), the largest explosion in the known Universe, is the first contemporary supernova to have been continuously observed from its beginnings in 1987 to its remnant phase, and provides new evidence for the asymmetrical trajectory of ejected matter.
“The material was ejected from the equator of the exploding star, contrary to what was expected,” said astrophysicist Karina Kjaer, lead author of the study, which will be published in Astronomy and Astrophysics.
The Rosetta Stone of supernovae
The supernova occurred in the Large Magellanic Cloud, a small nearby galaxy, close enough to Earth that the explosion could be seen by the naked eye in the Southern Hemisphere. There had not been such a close, visible supernova in almost 400 years.
“SN 1987A [is] a very important supernova,” said Kjaer. “It is called the Rosetta Stone of supernovae – it is the key to understanding them all.”
The international team of scientists, lead by Kjaer of the Queens University of Belfast, UK, are the first to have observed a three-dimensional view of the inner ejecta (matter ejected in an eruption) of a supernova.
Explosion left an imprint on inner material
“We are looking at the very last material to have left the star as it exploded, which is why determining its nature and direction reveal details about the explosion itself. In a way the explosion has left an imprint on this inner material,” Kjaer said.
The scientists observed SN 1987A using a new technique called ‘integral field spectroscopy’, which takes a picture like a normal camera, but records one more piece of information: the velocity of the material in each pixel. This provided a three-dimensional view of the inner ejecta.
The specialised instrument is part of the European Southern Observatory’s Very Large Telescope (VTL) in Chile.
The secrets of supernovae
For several years, scientists had believed that the inner material was ejected from the poles of the exploding star. These new observations have proved that this is not true, or not always true, with the revelation that the remnants of SN 1987A’s explosion were expelled from its equator, not its poles.
