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if a star is converted every bit of its mass.
into energy the conversion efficiency would
be 100%. however no star is this efficient in
its energy production stars with less than
1.3 solar masses convert hydrogen into
helium with an efficiency of only 0.7%.
besring in mind that aldebaram has a mass
of 2.32*10^30 kg. how long will it live if it
converts all of its hydrogen into helium with
an efficiency of 0.7%. 1 year = 365.25 days.
lifetime= years

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