The Kreutz family of comets
This group of sungrazing comets has produced many greats over the years
The German astronomer Henrich Kreutz was the first to note in 1888 that several comets that had been seen in the previous 50 years had passed perihelion at extremely close distances to the Sun, and had very similar orbital elements.
Today, these comets are named in his honour and all the members, which are now known to total over 2,000, have perihelion distances that range from 0.005 to 0.009 AU from the Sun’s centre. Known to come from the breakup of one large comet in the 12th century, they share other key orbital characteristics too, with aphelion distances around 170 AU from the Sun, orbital periods between 500 and 1,000 years and orbital inclinations of 140º.
The most notable members of the group are the Great March Comet of 1843, The Great September Comet of 1882 and Comet C/1965 S1 Ikeya-Seki. The last spectacular Kreutz comet – and the first one discovered using ground-based telescopes in 40 years – was C/2011 W3 Lovejoy in November 2011, which survived a perihelion pass of just 140,000km from the surface of the Sun and appeared post-perihelion as a ‘headless’ comet. Its nucleus had disintegrated completely and it then spawned a tremendous tail before fading out completely. Radiation and tidal forces from the Sun account for the demise of many of these comets as they are only tens of metres across.