(a) An RR Lyrae star has mass and radius . Using the pulsation constant , estimate…

PHYSICS · Subjective · Fermi University Physics · Astrophysics & Cosmology · Stellar structure, energy generation and evolution · Stellar structure, energy generation and evolution

Stars from the Inside, Ch Pulsating stars: the kappa mechanism, the Leavitt law and asteroseismology

Problem

(a) An RR Lyrae star has mass

M = 0.55\,M_\odot

and radius

R = 5.0\,R_\odot

. Using the pulsation constant

Q = 0.040\,\mathrm{d}

, estimate its radial fundamental pulsation period. (b) A solar-type subgiant, seen to show solar-like oscillations, has

\nu_{\max} = 900\,\mu\mathrm{Hz}

\Delta\nu = 55\,\mu\mathrm{Hz}

and

T_{\rm eff} = 5600\,\mathrm{K}

. Using the same solar calibration as before (

\Delta\nu_\odot = 135\,\mu\mathrm{Hz}

\nu_{\max,\odot} = 3090\,\mu\mathrm{Hz}

T_{{\rm eff},\odot} = 5777\,\mathrm{K}

), find its mass and radius.

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