How to Calculate Luminosity of an RR Lyrae Star?

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SUMMARY

The discussion focuses on calculating the luminosity of RR Lyrae stars using their pulsation period, surface temperature, and mass. Participants highlight the lack of specific equations for RR Lyrae, suggesting the use of the equation $$\Pi \approx \sqrt{\frac{3\pi}{2 \gamma G \rho}}$$ to derive luminosity. The relationship $$\frac{L}{L_{\odot}} = {\left ( \frac{R}{R_{\odot}} \right )}^2 {\left ( \frac{T}{T_{\odot}} \right )}^4$$ is proposed for calculating luminosity based on radius and temperature ratios. The consensus indicates that while the approach is plausible, further validation is necessary.

PREREQUISITES
  • Understanding of RR Lyrae variable stars
  • Familiarity with stellar luminosity equations
  • Knowledge of the relationship between temperature, radius, and luminosity
  • Basic grasp of astrophysical constants such as G (gravitational constant)
NEXT STEPS
  • Research the specific luminosity equations for RR Lyrae stars
  • Study the derivation and application of the equation $$\Pi \approx \sqrt{\frac{3\pi}{2 \gamma G \rho}}$$
  • Explore the impact of surface temperature on stellar luminosity
  • Investigate the differences between RR Lyrae and Cepheid variable stars
USEFUL FOR

Astronomy students, astrophysicists, and researchers focusing on variable stars and stellar luminosity calculations.

Gregg
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Homework Statement



Given pulsation period in days, (surface temperature) and mass of an RR Lyra variable star. How do you find luminosity?

Homework Equations



The relevant equations seem to be for finding the luminosity of Cepheids... there are no equations for Lyrae... Other than, absolute magnitude is 49 solar masses luminosities, for all RRs.

Should I use

$$ \Pi \approx \sqrt{\frac{3\pi}{2 \gamma G \rho}} $$ to get L from

$$\frac{L}{L_{\odot}} = {\left ( \frac{R}{R_{\odot}} \right )}^2 {\left ( \frac{T}{T_{\odot}} \right )}^4 $$ ?
 
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The Attempt at a SolutionI think that the first equation can be used to get an approximation of luminosity, but I'm not sure if it's the correct approach.
 

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