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Star Distances
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In article . com, "Hurt" writes: 4.22ly is approximately 266,695au. That would make, at most, the average brightness of all other stars to be approximately 1/(266695)^2 = 71126223025, or about 71 BILLIONTH! as bright as our Sun. The Sun has an apparent visual magnitude of -26.8, while Sirius, the next brightest star, has an apparent magnitude of about -1.5. That's a factor of 1.3E10 in apparent brightness. The faintest stars visible to the naked eye are a few hundred times fainter than Sirius. In response to another post in this thread, not all distance measurements rely on parallax. There's a geometric method for visual+spectroscopic binaries, the "Baade-Wesselink method" for variable stars, the "moving cluster method" (which as far as I can tell only works for the Hyades), and gravitational lens models for distant galaxies. Probably more. Parallax is still the "gold standard," though. -- Steve Willner Phone 617-495-7123 Cambridge, MA 02138 USA (Please email your reply if you want to be sure I see it; include a valid Reply-To address to receive an acknowledgement. Commercial email may be sent to your ISP.) |
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