This quantity is defined such that a difference in five corresponds to a hundred-fold difference in luminosity. For 10 points each:
[10e] Give this quantity that is proportional to the logarithm of the luminosity. This quantity’s “absolute” form is the value of its “apparent” form that an object would have at a distance of 10 parsecs.
ANSWER: magnitude [or bolometric magnitude; or absolute magnitude or apparent magnitude]
[10h] Because magnitudes are typically measured in specific passbands, these quantities must be added to account for radiant flux in other parts of the spectrum. For quasars, these quantities are typically computed relative to measurements at 3000 or 5100 angstroms.
ANSWER: bolometric corrections
[10m] The difference between magnitudes measured in different passbands defines one of these quantities. The x-axis of a Hertzsprung–Russell diagram is often one of these quantities computed between the B and V bands.
ANSWER: color index [prompt on index; accept B-V color]
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