Question

An expanding supernova remnant (SNR) with angular size 120 arcmin (1 degree equal to 60 arcmin.) was discovered in our Galaxy. If the remnant is at 12000 ly (light year) from us with a constant expansion velocity of 6,000 km*s^-1, when approximately did the progenitor star of the SNR explode? (speed of light : 3.0×10^5 km*s ^-1)

Answer 1

Answer:

The Crab Nebula (catalogue designations M1, NGC 1952, Taurus A) is a supernova remnant in the constellation of Taurus. The current name is due to William Parsons, 3rd Earl of Rosse, who observed the object in 1840 using a 36-inch telescope and produced a drawing that looked somewhat like a crab. Corresponding to a bright supernova recorded by Chinese astronomers in 1054, the nebula was observed later by English astronomer John Bevis in 1731. The nebula was the first astronomical object identified with a historical supernova explosion.