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Sitting slightly east of the second-brightest star in Ophiuchus is an old red dwarf1 star called Barnard's Star. Also known as Proxima Ophiuchi, or V2500 Ophiuchi, it is one of our nearest neighbours. Closer than any star except for Alpha Centauri and its two companions, it is, however, much too dim to be seen without a telescope.
- 4.22 ly Proxima Centauri
- 4.35 ly Alpha Centauri A
- 4.35 ly Alpha Centauri B
- 5.96 ly Barnard's Star
- 7.80 ly Wolf 359
The stars in the night sky seem to retain their positions relative to one another as if etched on a celestial sphere. Indeed, the same constellations that existed in ancient Greece still exist today. This is due to the fact that we are observing them from a great distance. However, the stars are moving, as a comparison of photographs will show. This motion is known as proper motion, and the star with the greatest proper motion is Barnard's Star. This star, 5.96 light years away, changes position one-sixth of a minute of arc3 every year.
Very few 9th magnitude stars get named after someone; this one did. It commemorates Edward Emerson Barnard (1857 - 1923) who noted its changing position in 1916. Also known as EE Barnard, this American astronomer was a pioneer in astrophotography. In 1881 he discovered C/1881-S1, the first of several comets. In 1892 he discovered Amalthea which is one of Jupiter's moons. In 1897 he was awarded the gold medal of the Royal Astronomical Society.
Barnard's Star is an old red dwarf with a magnitude of +9.54, rotating once every 130 days.
This star also has:
- A surface temperature of 3,170K
- A spectral classification of M4
- A mass of 0.18 of our Sun
- A position (in the year 2000)4: Right Ascension = 17 hrs 57' 49" Declination5 = +4° 41' 36"
It has long been suspected that Barnard's Star has a planetary system. One Dutch astronomer, Peter van de Kamp (1901 - 1995), even published reports of two planets there. Unfortunately, later study proved those claims were wrong and the data he submitted on them was rejected6. The star, however, is still on the list of NASA's Space Interferometry Mission (SIM).
Not to be confused with a project of the same name by the SEDS (Students for the Exploration and Development of Space) organisation, the Daedalus project was created in the 1970s by The British Interplanetary Society. The proposal was to send an unmanned probe to Barnard's Star, arriving 50 years after launch. This project would overcome the inherent problems in travelling to the stars by means of a Nuclear Pulse Engine7. The engine would run for close to two years, accelerating the probe to about 12% of the speed of light. One version of Newton's First Law of Motion states that:
An object will maintain its velocity until a force acts on it to change it.
Therefore when the probe arrived at its destination it would continue at 12% of light speed, and measures would have to be taken to slow down any components that were intended to remain in the star system. It may be decades yet before such a project is actually attempted.
Barnard's Star in Literature and Music
In The Hitchhiker's Guide To The Galaxy, Douglas Adams called this system a hyperspace junction used by Vogons where their fleets docked for retrofit. Also, Ford Prefect referred to it as a roundabout used by hitchhikers. Some of the other books mentioning it are:
- Legion of Space by Jack Williamson (1934)
- The Black Corridor by Michael Moorcock (1969)
- Rocheworld by Robert L Forward (1990)
- The Gardens of Rama by Arthur C Clarke and Gentry Lee (1991)
Just as Billy Joel wrote a song using a seres of historical events and people entitled 'We Didn't Start the Fire', the pop band Blur wrote a more laid-back song composed of astronomical places entitled 'Far Out' including the lyric:
Vega, Capella, Hadar, Rigel, Barnard's Star
These are all listed in their respective constellations: