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Is apparent magnitude of star, distance(in pc) and effective temperature enough to calculate its stellar radii or we need some extra information?

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  • $\begingroup$ You’ll also need its spectral type, at the very least. $\endgroup$ Commented Jan 8, 2022 at 10:34
  • $\begingroup$ You don't need any additional information. $\endgroup$ Commented Jan 8, 2022 at 10:41

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You need to find a bolometric correction from the effective temperature (this is reasonably insensitive to gravity and metallicity, which you don't know). Then convert the apparent magnitude into a bolometric magnitude and then into a flux. Then, I suppose you have to assume there is no extinction to estimate the intrinsic luminosity of the star by multiplying by $4\pi d^2$.

From there you can approximate the star as a blackbody and use Stefan's law, your intrinsic luminosity and the given temperature to estimate a radius.

So to answer your question directly: no. You need to know the extinction and, to get an accurate estimate, you would need to know the type of star, its chemical composition and use a better model than a blackbody for its spectrum.

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  • $\begingroup$ We can just use distance modulus formula if an approximation is required I suppose $\endgroup$ Commented Jan 9, 2022 at 17:50
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Yes

  1. Convert Apparent magnitude into absolute magnitude using distance modulus. 2.Then use stefan law and Flux Luminosity relationship.
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