 Solution

ID: past-exam-of-the-short-options-paper-of-the-physics-prelims-of-the-university-of-oxford/2021/s02/1/d/solution

TODO: the plotted location of Procyon B is missing from the damaged source diagram. The Stefan–Boltzmann law would determine the stellar radius from its effective temperature and bolometric luminosity:

\frac{R _{B}}{R _{⊙}} = (\frac{L _{B}}{L _{⊙}})^{1/2} (\frac{T _{⊙}}{T _{B}})^{2} .

A visual luminosity alone must first be converted with the appropriate bolometric correction. Procyon B is a white dwarf, so its small stellar radius and hot surface place it below the main sequence, rather than among giant stars or supergiants. This classification does not supply the missing numerical coordinates. A source-based numerical stellar radius cannot be claimed from the surviving image.^[ref]

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