Von Zeipel theorem

In astrophysics, the von Zeipel theorem states that the radiative flux F in a uniformly rotating star is proportional to the local effective gravity g_\textrm{eff}. Specifically,

F=-\frac{L(P)}{4\pi G M_{*}(P)}g_\textrm{eff}

where the luminosity L and mass M_{*} are evaluated on a surface of constant pressure P. The effective temperature T_\textrm{eff} can then be found at a given colatitude \theta from the local effective gravity

T_{\textrm{eff}}(\theta)\sim g_{\textrm{eff}}^{1/4}(\theta).[1][2]

The theorem is named after Swedish astronomer Edvard Hugo von Zeipel.


References

  1. ↑ von Zeipel, Edvard Hugo (1924). "The radiative equilibrium of a rotating system of gaseous masses". Monthly Notices of the Royal Astronomical Society 84: 665–719. Bibcode:1924MNRAS..84..665V.
  2. ↑ Maeder, André (1999). "Stellar evolution with rotation IV: von Zeipel's theorem and anistropic losses of mass and angular momentum". Astronomy and Astrophysics 347: 185–193. Bibcode:1999A&A...347..185M.