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Starry, Starry Night

Barnard's Star

Paul Kohlmiller

A pair of screen shots taken from Software Bisque’s The Sky 6 program were used to show how Barnard’s Star will move over the next 5 years. The two images were overlaid using GSC 425:262 as an alignment point. The alignment star has a magnitude of 11.2 while Barnard’s Star has a magnitude of 9.6. You see a small amount of movement from other, dimmer stars in the area. If you can’t wait 5 years then check out the short animation at


All stars are in motion. It is difficult for us to see this movement, called a star’s proper motion, for two reasons. First, all of the stars close enough to detect the motion are moving in the some direction that we are. Second, even nearby stars are so far away that motion is hard to see. But we do have Barnard’s star. This star is not only not moving toward it us, at its current relative speed (67 miles/second) in a few thousand years (11,800 CE) it will actually be the closest star coming within 3.85 light years. Currently it is less than 6 light years away. The biggest problem in detecting the motion of this star is that it is relatively dim. It’s an M class dwarf with a magnitude of 9.6.

As the name suggests, this star was discovered by Edward Barnard in 1916. Barnard worked at Lick Observatory shortly after it started operations. It was at Lick that Barnard discovered the Jovian moon Amalthea - the first Jovian moon discovered after Galileo. Later Barnard moved to the Yerkes Observatory which is where he discovered this star.

But for the detection of proper motion, the important thing is how quickly does the star move against the background of other stars. The proper motion of Barnard’s star is 10.4 arc-seconds per year. This works out to one lunar diameter every 180 years. You may not have 180 years to spare but lets be optimistic and say 5 years. The picture shows that Barnard’s star will be in a clearly different position 5 years from now.

Only the Alpha Centauri star system is closer than Barnard’s star. It is has the designation V2500 Ophiuchi which tells you that this star is also variable. The variability is apparently due to magnetic effects which cause occasional flares. For an earth-size planet to get the same amount of energy from Barnard’s star as it does the sun, the planet would have to be 0.06 astronomical units away resulting in a 13 day “year”. But hey, winter would only be 3 days long. But then those flares would incinerate everything.

The actual speed of Barnard’s star is not unusual. But the low metallicity of the star shows that it belongs to the halo of the galaxy and not to the disk. It is just passing through.

The actual speed of the star is not so unusual. For a star that is really moving see Mira in Cetus - a star that is moving so fast it leaves a trail.


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