Barnard's star

/bahr"neuhrdz/

a red dwarf star of magnitude 9.5 in the constellation Ophiuchus, having the largest known proper motion and being the nearest star to earth (5.9 light-years) beyond the Alpha Centauri system.

[after Edward E. Barnard (1857-1923), American astronomer, its discoverer]

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Star about six light-years away from the Sun, next nearest the Sun after the Alpha Centauri system, in the constellation Ophiuchus.

Named for Edward Emerson Barnard (b. 1857

d. 1923), who discovered it in 1916, it has the largest proper motion of any known star. It is gradually nearing the solar system. The star attracted astronomers' attention in the 1960s when its proper motion was claimed to show periodic deviations attributed to the gravitational pull of two planets (see planets of other stars). The deviations were later proved to be artifacts of measurement.

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▪ astronomy

      third nearest star to the Sun (after Proxima Centauri and Alpha Centauri's A and B components considered together), at a distance of about 6 light-years. It is named for Edward Emerson Barnard (Barnard, Edward Emerson), the American astronomer who discovered it in 1916. Barnard's star has the largest proper motion of any known star—10.25 seconds of arc annually. It is a red dwarf star with a visual magnitude of 9.5; its intrinsic luminosity is only 1/2,600 that of the Sun.

      Because of its high velocity of approach, 108 km (67 miles) per second, Barnard's star is gradually coming nearer the solar system and by the year 11,800 will reach its closest point in distance—namely, 3.85 light-years. The star is of special interest to astronomers because its proper motion, observed photographically between the years 1938–81, was thought to show periodic deviations of 0.02 seconds of arc. This “perturbation” was interpreted as being caused by the gravitational pull of two planetary companions having orbital periods of 13.5 and 19 years, respectively, and masses of about two-thirds that of Jupiter. However, this finding has not been supported by results from other methods of detection.

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