# Relationship between mass and surface temperature of a star

1. May 5, 2011

### jewfro420

i was wondering if there is a relationship between mass and temperature that would allow me to calculate the surface temperature of a blue super giant of 24 solar masses?

2. May 9, 2011

### Staff: Mentor

I think you would need to know things like age of the star, makeup of the star, and similar stuff.

3. May 11, 2011

### qraal

It's roughly T = T(sol)*M0.5 with M in solar masses.

4. May 11, 2011

### FtlIsAwesome

By using T = 5,778 * 24^0.5
I get 28,306 K, which is slightly outside the 30,000 K - 52,000 K range for O class stars.
So either I didn't use it right, or it doesn't work for O class stars.

Probably what will be an important factor in determining surface temp is the spectral class (O B A F G K M), and luminosity.

5. May 11, 2011

Staff Emeritus
24 solar masses is enormous. This is more than Rigel; it's looking like something like Alnitak. Which, by the way, is around 30K. Getting within 10% with a hand-wavy formula is pretty good.

6. May 11, 2011

### Staff: Mentor

Am I incorrect in thinking that age, metal content, and other various factors would affect the stars temp as well?

7. May 20, 2011

### jewfro420

so basically i think that there is no relationship between mass and temperature for non main sequence stars so this cant be done. cheers for your help anyways

8. May 22, 2011

### FtlIsAwesome

There might be a correlation between brightness/magnitude/luminosity and temperature, but that's just my guess.