If a giant molecular cloud is 60 pc in diameter and a shock wave can sweep through it in 3 million years, how fast is the shock wave going in kilometers per second?

If a protostellar disk is 210 AU in radius and the disk plus the forming star together contain 4 solar masses, what is the orbital speed at the outer edge of the disk in kilometers per second? (Hint: Use the circular orbital velocity formula )

(a) Rank the following components of the interstellar medium in order of the wavelengths at which they are observed, longest wavelength first: clouds of neutral hydrogen, coronal gas, interstellar dust, nebulae. Longest to Shortest?   (b) Rank the same material in order of decreasing temperature from hottest to coolest. Hottest to Coolest?

If an open cluster contains 650 stars and is 27 pc in diameter, what is the average distance between the stars? (Hint: On average, what share of the volume of the cluster surrounds each star?)

A supernova’s energy is often compared to the total energy output of the Sun over its lifetime. Using the Sun’s current luminosity, calculate the total solar energy output, assuming a 1010 year main-sequence lifetime. Using Einstein’s formula E=mc2 calculate the equivalent amount of mass, expressed in Earth masses. [Hint: The total energy output of the Sun over its lifetime is given by its current luminosity times the number of seconds in a year times its ten billion-year lifetime; ; mass of earth = 6×1024kg; c = 3×108m/s. Your answer should be 200-300 Earth masses.]

if a protostellar disk is 260 au in radius and the disk plus the forming star together contain 7 solar masses what is the orbital speed at the outer edge of the disk in km per second. use the circular orbital velocity formula

How many years? Thank you!

If a giant molecular cloud has a diameter of 56 pc and drifts relative to nearby objects at 19 km/s, how long (in yr) does it take to travel a distance equal to its own diameter?

If a contracting protostar is five times the radius of the sun and has a temperature of only 2000 K, how luminous will it be?

If a giant molecular cloud is 60 pc in diameter and a shock wave sweeps through at 25 km/s, how long will it take the shock wave (in years) to sweep through the cloud?