- #1
wolf1728
Gold Member
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I see there have been many postings about this topic in this forum.
The formula for this relation is Luminosity = Mass^3.5
Taking logs of both sides we get log (lum) = 3.5 * log (mass)
and using a little algebra we find that the exponent (3.5) should equal log (lum) ÷ log (mass)
I have selected stars from a table located here: http://www.essex1.com/people/speer/main.html
and I have computed what the exponent value should be in each case.
STAR Lum Mass EXP
Orionis C 30,000.00 18.00 3.566653
Becrux 16,000.00 16.00 3.491446
Spica 8,300.00 10.50 3.837759
Achernar 750.00 5.40 3.925568
Rigel 130.00 3.50 3.885439
Sirius A 63.00 2.60 4.336039
Fomalhaut 40.00 2.20 4.678604
Altair 24.00 1.90 4.951367
Polaris A 9.00 1.60 4.674910
Eta Scorpii 6.30 1.50 4.539354
Procyon A 4.00 1.35 4.619371
Alpha Centauri A 1.45 1.08 4.827943
The Sun 1.00 1.00
Mu Cassiopeiae 0.70 0.95 6.953637
Tau Ceti 0.44 0.85 5.051600
Pollux 0.36 0.83 5.483033
Epsilon Eridani 0.28 0.78 5.123395
Alpha Centauri B 0.18 0.68 4.446371
Lalande 21185 0.03 0.33 3.162872
Ross 128 0.0005 0.20 4.722706
Wolf 359 0.0002 0.10 3.698970
No matter whether we concentrate on low mass or high mass stars, we see that the exponent value varies quite a bit .
Does anyone know why there is so much variance in the mass luminosity relation?
The formula for this relation is Luminosity = Mass^3.5
Taking logs of both sides we get log (lum) = 3.5 * log (mass)
and using a little algebra we find that the exponent (3.5) should equal log (lum) ÷ log (mass)
I have selected stars from a table located here: http://www.essex1.com/people/speer/main.html
and I have computed what the exponent value should be in each case.
STAR Lum Mass EXP
Orionis C 30,000.00 18.00 3.566653
Becrux 16,000.00 16.00 3.491446
Spica 8,300.00 10.50 3.837759
Achernar 750.00 5.40 3.925568
Rigel 130.00 3.50 3.885439
Sirius A 63.00 2.60 4.336039
Fomalhaut 40.00 2.20 4.678604
Altair 24.00 1.90 4.951367
Polaris A 9.00 1.60 4.674910
Eta Scorpii 6.30 1.50 4.539354
Procyon A 4.00 1.35 4.619371
Alpha Centauri A 1.45 1.08 4.827943
The Sun 1.00 1.00
Mu Cassiopeiae 0.70 0.95 6.953637
Tau Ceti 0.44 0.85 5.051600
Pollux 0.36 0.83 5.483033
Epsilon Eridani 0.28 0.78 5.123395
Alpha Centauri B 0.18 0.68 4.446371
Lalande 21185 0.03 0.33 3.162872
Ross 128 0.0005 0.20 4.722706
Wolf 359 0.0002 0.10 3.698970
No matter whether we concentrate on low mass or high mass stars, we see that the exponent value varies quite a bit .
Does anyone know why there is so much variance in the mass luminosity relation?
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