Supernova SN1987

2011 Hubble Space Telescope - SN1987

Supernova SN1987 is making the news again! Talk about fun that keeps up giving. This time the outer ring has gotten brighter as seen on this Hubble Space Telescope image to the right. The interesting question is why? But before we can answer that, it is important to define what we are talking about. A supernova is the explosion of a massive star, much more massive than our Sun. The physics that explain this explosion are complicated to say the least. But the important fact is that there was a star, it blew itself to smithereens when its core could not sustain the gravitational forces that were holding the star together. What remains is a remnant, either a blackhole or a neutron star.  

Wide Field View of the LMC, with Rolf Wahl Olsen inset.
This is an amateur image and inset, to put things into perspective.
Image from Bert (avadonk) IceInSpace

What does SN1987 stands for? The first 2 letters are supernova, the remaining 4 digits are the year it was discovered. Now to answer the previous question, why now? Well, scientists like to revisit interesting targets from the past and using the Hubble Space Telescope, they have found that the outer ring of this supernova is brighter. Why would this be? The simple explanation is that 20,000 years ago the host star was "shedding" material into space.  This star material began its expansion into space as seen by the ring around the SN.   The shock of the SN has finally caught up to this material and it is glowing in all wavelengths for us to see.

153 x 15s taken on 27/11/2010 with 10" Newtonian
f/5 and ToUCam Pro SC1, no filter, no guiding
Image Rolf Wahl Olsen, 2010

To the right an amateur image of SN1987 from Australia, using a 12" Newtonian telescope and a webcam at focal ratio f/5. Notice the difference in spatial resolution between HST and this image from an amateur. Rolf has done an outstanding job considering this image is done from the ground, with a telescope that has an aperture 8 times smaller than Hubble and with an off the shelf webcam. You can see the pink nebulosity clearly on his image.   You might ask well how come we can't image something from the ground like the Hubble does?   The answer is all around us...  Earth atmosphere.   It limits the spatial resolution we can obtain with telescopes.   That is, around a few arc seconds on a perfect dark night for amateurs and for professionals at the top of a mountains it is shy below an arc second.