SOHO images comet's close encounter with Sun

17 Jun 2002

NASA, the European Space Agency, and the Naval Research Laboratory (NRL) have released a set of unprecedented images representing a time lapse movie of Comet Hyakutake making its close approach to the Sun. The observations were made with the NRL-built Large Angle Spectrometric Coronagraph (LASCO) instrument on the Solar and Heliospheric Observatory (SOHO) spacecraft. The comet, estimated to have an orbital period of 10,000 years, came within about 20 million miles of the Sun and is seen in the images against the background of the million-degree hot outer atmosphere of the Sun, the corona.

The LASCO images show the head of the comet, and clearly visible are three separate tails that behave differently as Hyakutake swings around the Sun. These tails are made of different materials which react differently with their environment. Heavy particles follow the comet in its orbit without being redirected by an outside force while the light dust particles are lining up away from the Sun and are driven by the Sun's intensive radiation. Finally, atomic particles are repelled from the comet by the solar wind and presumably line up with the magnetic field of the solar corona. The comet's tails could clearly be seen changing their relative direction over the seven day observation period as the Sun's forces acted upon them.