1. Estimate the kinetic luminosity in the jet of HH 34. How does this compare to the total luminosity of the protostar thought to be the source of the jets?
2. FU Orionis (who comes up with these names?) brightened by over a factor of 100 more than fifty years ago. If this sudden brightening coincided with the start of a stellar jet that propagated as fast as the HH 34 jet, how far would the head of the jet reached by now? Why is the timescale of 50 years perhaps not appropriate for the period of variability of stellar jets? Would the observation of such variability make for a good PhD thesis project?
3. Estimate the lifetime for a 10 solar mass star on the main sequence to give off energy stored from gravitational collapse.
4. How much mass per second is the Sun converting to energy through thermonuclear fusion? How long will the Sun survive by burning Hydrogen into Helium?
5. Using the mass-luminosity relationship (page 103 of your text), estimate the Hydrogen-burning lifetime of stars on the main sequence as a function of mass (Use the approximate relation that the radius of a star on the main sequence varies as mass to the 0.7 power).