Final answer:
The rings of gas around Supernova 1987A originated from material expelled by the star when it was a red giant, which later was hit by the supernova's shockwave, causing bright spots as the materials collided. Observations by the Hubble Space Telescope have been critical in studying these developments.
Step-by-step explanation:
The origin of the rings of gas surrounding Supernova 1987A can be traced back to when the star was a red giant, approximately 30,000 years before it became a supernova. During its red giant phase, the star expelled material which formed a ring. When the star exploded as Supernova 1987A, the shockwave propelled high-speed gas into this pre-existing ring, causing collisions that heated the gas and made the ring glow brightly. Hubble Space Telescope images reveal the increasing number of bright spots over time as the supernova material continues to collide with the ring, further illuminating it and providing insights into the nuclear processes within massive stars.
Velocity of Supernova Material
Given that the ring's radius is approximately 0.75 light-year from the location of Supernova 1987A, and the ring started interacting with the supernova material in 1997 (10 years after the explosion), we can calculate the velocity of the supernova material. To find the velocity, we convert the radius of the ring from light-years to kilometers, and then divide this distance by the time in seconds over which the interaction has been taking place.
Time to Illuminate the Ring
The ring around SN 1987A initially became illuminated when photons from the supernova's blast wave interacted with the material in the ring. Assuming the ring is 0.75 light-year away from the supernova, the energetic photons would take about 0.75 year to reach and illuminate the ring after the supernova event.