Astronomy problem help?
I'm new to astronomy, can some please help with steps? Thank you!
If the sun’s luminosity is given as 1 L*, what is the luminosity of an A0 type star with twice the radius
of the sun (surface temperature 5800K)?
I'm new to astronomy, can some please help with steps? Thank you!
If the sun’s luminosity is given as 1 L*, what is the luminosity of an A0 type star with twice the radius
of the sun (surface temperature 5800K)?
Comments
There's no such thing as an A0 star with a temperature of 5800K.
For a main sequence star of type A0...
M = 2.65 solar masses
R = 1.74 solar radii
L = 43.6 times the sun's luminosity
T = 11250 K
absolute magnitude = +0.642
B−V color index = −0.1
λmax = 2576 Å
time on main sequence = 608 million years
There is a nice formula linking L, T with the radius R, derived from Stephen's Law in terms of ratios (of Solar parameters):
L = R² T⁴,
= 4 (55 / 29)⁴ = 51.7510 times
bringing it to an absolute magnitude of +0.545.
That is, since A0 star has surface temperature of about 11000_K* (peaking at λ=0.263μ in UV).