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Barnard's star has radial speed ,
proper motion ,
and parallax 0.546''.
Parallax is the angle by which a star shifts
against its background when measured from
the two extreme points
of a baseline of ,
i.e. observing the star from Earth three months apart.
A piece of trivia: before the recent discovery
of extrasolar planets using the Doppler-recoil technique,
Barnard's star was a favourite target of astrometric
planet searches because of its proximity to Earth.
(An astrometric search looks for a wobble
in the path of the star across the sky.)
Several of these searches even claimed success, though without
confirmation. It is now known, from Doppler-recoil,
that Barnard's star does not have planets --
at least, not massive ones like Jupiter.
What is the distance to Barnard's star in pc?
What is the tangential speed of Barnard's star?
What is the magnitude and direction of the velocity
of Barnard's star?
Express the direction as an angle with respect to the
How far, in pc, will Barnard's star be from Earth at its point
of closest approach?
In how many years will it reach its point of closest approach?
Tue Oct 19 13:15:33 PDT 1999