A sample question for a test
The Sun has an effective temperature of Ts = 5800 K,
while the star 40 Eridani has an effective temperature of
Te = 5100 K.
Treat both as perfect blackbodies.
- At what wavelength will the Sun produce the peak
specific intensity?
- Consider one square meter of each star's photosphere.
The Sun will produce more power -- integrated over
all wavelengths -- from this one square meter than
will 40 Eridani.
What is the ratio of
Power emitted by 1 sq. m. of the Sun
-----------------------------------------
Power emitted by 1 sq. m. of 40 Eridani
- But in real life, the total power emitted at all wavelengths
by the Sun exceeds that emitted at all wavelengths by
40 Eridani by a factor of 2.88.
Explain quantitatively the physical reason for this difference.
It's possible there might be a bonus section added to one question
for a small additional credit (+10% or +15%), like this:
Bonus!
- The absolute bolometric magnitude of the Sun is 4.83.
What is the absolute bolometric magnitude of 40 Eridani?