Comet IRAS-Araki-Alcock

Right ascension:   8:56:55   Magnitude:  2.4
    Declination:  27:06:16

Image:  LWR 15909
 Date:  1983 May 11 20:28 UT

Exposure duration:  100 min

IUE observed Comet IRAS-Araki-Alcock (1983d) as the comet passed less than 5 million kilometers from Earth, the closest approach of a comet since Comet Lexell in 1770. IUE detected molecular sulfur (S2) for the first time in any celestial object (the seven emission lines to the upper left of the bright OH line at lower right). Carbon monosulfide is also visible in the spectrum. A long-period comet, it shows characteristically spherical distribution of outgassing. Shorter-period comets, which have lost many of their volatiles over the course of repeated solar exposures, have more localized jets or geysers.
Last updated: 08 April 1998
Obtained from IUE project at Goddard Space Flight Center