Sungrazing comets observed by the solar maximum mission coronagraph

Abstract

Ten sungrazing comets were discovered by the High Altitude Observatory's white light coronagraph on the NASA Solar Maximum Mission spacecraft during an observing period which covered about 6 years. In addition, observation of another sungrazing comet discovered by the SOLWIND coronagraph was confirmed. The comets exhibited a wide range of brightness near the Sun, spanning roughly 8 astronomical magnitudes. No comets were observed postperihelion, and no discernible coronal effects could be detected as a result of any comet disappearance. The comet apparent motions and orientation of tails are consistent with all of the comets belonging to the Kreutz sungrazer group, a conclusion in support of the orbital analysis of nine of the objects by Marsden (1989). The observing programs employed by the instrument to detect coronal mass ejection events are shown to be well-suited for the detection of sungrazers. The appearance of these comets is seen to be highly episodic over the time period of SMM coronagraph operation. Estimates of the comet head properties, including size, are offered, based upon the observed comet behavior.