The Astrogators’ Guide to

Barnard’s Star

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    Also known as Barnard’s Runner and Proxima Ophiuchi, this star has an age and speed that imply that it’s a member of the galactic halo merely passing through the galactic disc. Any planets that it may have are likely to be nothing more than gas balls, containing less of the heavy elements than Jupiter or Saturn do.

Location in Space

Radial Distance:

    Parallax = 0.5454±0.0003 arc-sec, which leads to;

        1. 5.98 ± 0.003 lightyears (1.834±0.001 parsecs).

        2. 378,190 ± 208 AU.

Equatorial Coordinates:

    Right Ascension; 17 hr, 57 min, 48.5 sec - 5.325t sec.

    Declination; +4 deg, 41 min, 36 sec +1033.777t arc-sec.

        [elapsed time measured in centuries, Jan 2000 is t = 0]

    Imagine standing on the north side of a plane in which Earth’s equator lies with the north celestial pole directly overhead and look toward the First Point of Aries (now in Pisces just southeast of the Circlet). Then look eastward (to the left) by 269-1/2 degrees and then north (up) by 4-2/3 degrees. The star lies just east (to the left) of Beta Ophiuchi.

Ecliptic Coordinates:

    Ecliptic Latitude; +26.1993 deg + 1033.429t arc-sec.

    Ecliptic Longitude; 295.0868 deg - 84.255t arc-sec.

        [elapsed time measured in centuries, Jan 2000 is t = 0]

    Look toward the First Point of Aries (the point on the sky that the sun occupies on the first day of spring), shift your gaze eastward along the Ecliptic (the line that the sun traces through the Zodiac in the course of a year) by 295 degrees, and then shift your gaze northward by 26 degrees along a line perpendicular to the Ecliptic.

Galactic Coordinates:

    Galactic Latitude; +14.0627 deg +882.822t arc-sec.

    Galactic Longitude; 30.867 deg - 543.78t arc-sec.

        [elapsed time measured in centuries, Jan 2000 is t = 0]

    Look toward the radio source Sagittarius-A by casting your gaze across the Orion-Sagittarius Gap toward the Sagittarius-Carina Arm of the galaxy and at a point about six degrees south of the Ecliptic on the west (right) side of Sagittarius and two degrees south of X Sagitarii (the point of the arrow in the Archer’s bow). Then move your gaze in an easterly direction along the plane of the Milky Way by about 31 degrees. Then tilt your gaze by 14 degrees in either a northerly direction, more or less upward and to your right, at right angles to the plane of the Milky Way.

Annual Proper Motion

    in Right Ascension = -0.79871 arc-sec/yr = 1.4644 AU/yr = 6.942 km/sec.

    in Declination = +10.33777 arc-sec/yr = 18.954 AU/yr = 89.851 km/sec.

        Total Proper Motion = 10.3683 arc-sec/yr = 19.01 AU/yr = 90.119 km/sec in a direction 4.418˚ counterclockwise from due celestial north, 0.24˚ counterclockwise from due Ecliptic north, and 27.21˚ counterclockwise from due Galactic north.

    in Radial Distance = -106.8 km/sec = 22.53 AU/yr.

        Total motion = 29.4785 AU/yr = 139.74 km/sec.

    From the present; in 9,804 years Barnard’s star will reach its perihelion 3.856 lightyears (243,848 AU) from Sol in the north-central part of the constellation of Auriga after crossing 130.16 degrees of sky.

Orientation in Space

We generally only get this information for binary stars.

The Star Itself

        Diameter; 208,785 – 278,380 km (0.15 – 0.20 Sol).

        Harvard Class; M4Ve (3,134±102 Kelvins).

        Age; 10 billion years

        Mass; 0.15 – 0.17 Sol.

        Brightness; 0.0004 Sol.

        Habitable zone: 0.089±0.005 AU, 21±2 days.

        Surface composition: not found. The star is a BY Draconis variable.


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