SN 1987A, as photographed by the Hubble Space Telescope in 2006. Credit: NASA, ESA, P. Challis and R. Kirshner (Harvard-Smithsonian Center for Astrophysics)
When a large star ends its life, it does not go quietly into the night. Instead, it explodes in a fantastic supernova that rips the star apart, leaving astronomers to study its remnants for decades, sometimes centuries.
Astronomers using the European Southern Observatory's Very Large Telescope have made it possible for you to explore the 3-D structure of a remnant of a recent supernova, SN 1987A. And the results show that the explosion is just as messy as we thought it might be.
Since we cannot make a star go supernova at our convenience, astronomers have been exploding model stars in their computers in order to study the intricate details. Time and time again, these simulations show that the supernovae do not behave in a nice symmetrical manner.
Instead, large instabilities form as the star collapses upon itself, making the resulting explosion asymmetric. Supernova remnants show evidence of such asymmetries, though the main show was over hundreds of years ago.
In 1987, a large, but otherwise ordinary star in the Large Magellanic Cloud ended its life with a bang, exciting astronomers everywhere who could now study a supernova from the very beginning, and not so far away. Using the VLT, the group led by Karina Kjaer mapped the velocity of the gas using a technique called integral field spectroscopy. That is, they carefully measured the motion along our line of sight at each point by looking at the redshift or blueshift of emission lines in the infrared. The resulting 3-D view makes for quite a sight.
These new observations show that the innermost ejecta, or material left over from the explosion, is indeed asymmetrical, as if there was a large initial instability, confirming the predictions of so many models. And that kind of agreement is exactly what science needs to move forward.
This work is published in Astronomy & Astrophysics for July 2010, and the preprint is available on astro-ph.