The star HD 12661 is located at a distance of 121 light years, on the border of the constellation Aries near Triangulum. The planet's period is 250 days, with an average distance from its star of 0.80 AU. (One astronomical unit, or AU, is 93 million miles, the distance from the Earth to the Sun.) The lower limit on its mass is 2.8 Jupiter masses. The star HD 92788 is located 104 light years from Earth in the constellation Sextans. The planet's period is 341.7 days, and it orbits at an average distance of 0.98 AU. Its mass is at least 3.7 Jupiter masses. The star HD 38529 is 137 light years away, in the constellation Orion. The planet's period is 14.3 days; its average distance from the star is 0.13 AU. The lower limit on its mass is 0.77 Jupiter masses. a) Find the mass of the three stars listed above. b) Determine how many times more or less massive these stars are than the Sun. c) Explain why the second of these three planets is the most interesting to planetary scientists.