I know that the light coming from Proxima Centauri is not bright enough to make it naked-eye visible from the Earth. Is the Sun naked-eye visible from Proxima Centauri?
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Is the Sun visible from Proxima Centauri to human eyes?
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asked Aug 24 '16 at 19:57
Patrick
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2 Answers
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Alpha Centauri A and B happen to be rather similar to Sol, and their absolute magnitudes are 4.38 and 5.71 respectively (Wikipedia). Add them together and you get absolute magnitude 4.10 (the scale is logarithmic, and backward). Sol, with absolute magnitude 4.83, should look 0.73 magnitude dimmer than αCen at the same distance, so magnitude +0.46, quite bright.
answered Aug 25 '16 at 7:00
Anton Sherwood
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The key to this is the so called Absolute Magnitude, which represents the visual magnitude from a distance of 10 parsecs (about 32 light years). The sun is much brighter than Proxima Centauri. It has an absolute magnitude of 4.8, and at a distance of 4 light years (the distance of Proxima), it would be be somwhat brighter than 1st mag, and so very easily visible with the unaided eye.
answered Aug 24 '16 at 20:29
Dr Chuck
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Is the Sun visible from Proxima Centauri to human eyes?
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I know that the light coming from Proxima Centauri is not bright enough to make it naked-eye visible from the Earth. Is the Sun naked-eye visible from Proxima Centauri?
asked Aug 24 '16 at 19:57
Patrick
4134 silver badges5 bronze badges
4134 silver badges5 bronze badges
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Alpha Centauri A and B happen to be rather similar to Sol, and their absolute magnitudes are 4.38 and 5.71 respectively (Wikipedia). Add them together and you get absolute magnitude 4.10 (the scale is logarithmic, and backward). Sol, with absolute magnitude 4.83, should look 0.73 magnitude dimmer than αCen at the same distance, so magnitude +0.46, quite bright.
answered Aug 25 '16 at 7:00
Anton Sherwood
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The difference between magnitude 0.4 (your answer) and magnitude 0.46 (my answer) is accounted for by the distance between Proxima and Alpha A/B, which I ignored for simplicity. It's not a factor of 1.4. - Anton Sherwood Aug 27 '16 at 3:56
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