A planetary nebula photographed 20 years ago and then photographed again today has increased its radius by 0.6 arc seconds. If Doppler shifts in its spectrum show that it is expanding at a velocity of 20 km/s, how far away is it? (Hints: First fi gure out how many parsecs it has increased in radius in 20 years. Then use the small-angle formula, Chapter 3.)
We need at least 10 more requests to produce the solution.
0 / 10 have requested this problem solution
The more requests, the faster the answer.