Star Distances

[Newsgroups trimmed]

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
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