A neutron star has a radius of 10 km, and a temperature of 1 million K. What is its luminosity?
Answer: 0.2 solar luminosities
The formula to identify the luminosity of a star is,
L / L0 = (R/R0)2(T/T0)4
Here, R0 = 6.96*105 km
T0 = 5800 K
L / L0 = (10 km/6.96*105 km)2(1,000,000 K/5800 K)4
= 0.2 solar luminosities
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