Supernova 1987A (3) ...

The following computer enhanced Hubble Space Telescope image shows the interior ring around Supernova 1987A over a three year period from 1994 to 1997.

The Supernova Remnant

The white cresecent-shaped material near the center in the above right image is the visible remains of the progenitor star (the expanding supernova remnant). It is presently expanding at a velocity of about 3000 km/s, covering almost twice the distance from the Earth to the Sun each day.

Illuminating the Ring
As noted previously, this ring is material ejected from the star well before it exploded that is now glowing because it is being irradiated by light from the supernova (the bright region in the center). The glow from the central ring has been decreasing slowly for the last 10 years as the intensity of illuminating radiation has decreased.

Arrival of the Blast Wave
However, notice the spot marked with the arrow that has brightened since 1994 (the bright lower left spot is a star that is just in the line of sight and is not part of the system). This is thought to be the first indication of the blast wave from the supernova overtaking the more slowly expanding ring. If so, we may expect over the next several years that the central ring will begin to glow more brightly and become a rejuvenated source of X-rays and RF emission.

Illumination of the Central Ring
The adjacent animation illustrates schematically the illumination of the central ring around Supernova 1987A. The initial explosion illuminates the previously ejected ring by UV radiation. As the UV fades, so does the brightness of the ring. However, as the expanding blast wave reaches the ring it begins to glow again because of collisions between the rapidly expanding blast and the more slowly expanding ring. This animation may be viewed as covering about a 10-20 year period following the supernova explosion and is intended to convey the basic idea only. The details are probably much more complex.