Astronomy & space · University
Relative luminosity of a blackbody star
Use the effective-temperature blackbody luminosity model and compare the same reference quantities.
Method and conditions
Use the effective-temperature blackbody luminosity model and compare the same reference quantities.
L/Lref = (R/Rref)²(T/Tref)⁴
Worked examples
In a blackbody model a star has radius 1.5 times a reference star and effective temperature 1 times the reference. Find L/Lref. Round the final result to 4 decimal places if needed.
Stefan–Boltzmann scaling gives (1.5)²(1)⁴.
2.25
In a blackbody model a star has radius 2 times a reference star and effective temperature 1.75 times the reference. Find L/Lref. Round the final result to 4 decimal places if needed.
Stefan–Boltzmann scaling gives (2)²(1.75)⁴.
37.5156
Try it
In a blackbody model a star has radius 2.5 times a reference star and effective temperature 2 times the reference. Find L/Lref. Round the final result to 4 decimal places if needed.
In a blackbody model a star has radius 2.5 times a reference star and effective temperature 0.5 times the reference. Find L/Lref. Round the final result to 4 decimal places if needed.
Check your work
Answers and marking notes
- 100
Stefan–Boltzmann scaling gives (2.5)²(2)⁴.
- 0.3906
Stefan–Boltzmann scaling gives (2.5)²(0.5)⁴.
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