•
•Question 6 (2 points) In the movie Blade
Runner, replicant Roy Batty
was compared to a candle: "A candle that burns twice as bright burns half as long." Star lifetimes are
more complex than this
(i.e.,the relationship is not linear). If the lifetime of a star is half that of the sun, how luminous is it?
a.1 solar luminosity
•b.2 solar luminosities
•c.0.5 solar luminosities
•d.1.3 solar luminosities
•e.2.6 solar luminosities
•
•Need to use L = M3.5 and Lifetime = M -2.5 (all in solar
units)
•First, Lifetime = ½ solar = (M) -2.5, solve to get M (1.3
solar masses)
•Plug
into the other equation to get 2.6 solar luminosities. It’s really just a matter of being able to solve these
exponential equations comfortably
with your calculator.