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- I'm attempting to understand fully the distance ladder we use in astronomy to determine the distance to stars that are too far away for parallax to work.
I'm attempting to understand fully the distance ladder we use in astronomy to determine the distance to stars that are too far away for parallax to work. I understand we calibrate to a standard candle data of period vs luminosity for the cepheid variable stars in a group. Then from knowing the absolute magnitude M we can use the distance modulus equation involving the term m - M to figure out the absolute distance.
But am I understanding this correctly?
m = apparent magnitude as it the brightness of the star as it appears with the telescope
M = absolute magnitude, which is determined by... What?
Ok, that's the gap in my knowledge about this subject.
How do we know absolute brightness of a distant star?
And how does the period versus luminosity graph determine absolute magnitude? (Isn't that luminosity a relative measurement?)
Please forgive the nativity of my question.
But am I understanding this correctly?
m = apparent magnitude as it the brightness of the star as it appears with the telescope
M = absolute magnitude, which is determined by... What?
Ok, that's the gap in my knowledge about this subject.
How do we know absolute brightness of a distant star?
And how does the period versus luminosity graph determine absolute magnitude? (Isn't that luminosity a relative measurement?)
Please forgive the nativity of my question.