Groundbased Observations of the Sun's Corona Following the Perihelia of Sungrazing Comets

During the period 1979-1989, two spaceborne coronagraphs discovered 16 sungrazing comets in observations of the white-light corona. All of the comets discovered by NRL's Solwind telescope on the USAF satellite P78-1 and HAO's C/P telescope on NASA's SMM were members of the Kreutz family of sungrazers. All of these comets were observed in the hours prior to their individual perihelia, but none were detected post-perihelion by the spaceborne coronagraphs. Further, none of these comets were directly detected by groundbased observers. There was, however, a single report by Czech observers of a coronal enhancement in Fe X following the first Solwind comet. To investigate the possibility of a cometary signature in the solar atmosphere we examined groundbased coronal observations made at the National Solar Observatory site at Sacramento Peak with the Fisher-Smartt Emission Line Coronal Photometer. For 13 of the 16 comets described above, there were synoptic observations made at 5303A (Fe XIV) at Sacramento Peak both the day before and the day after the comets' perihelia. For a few cases, there were also scans at 5694A (Ca XV) and 6374A (Fe X). We report here on this work in progress. *Operated by AURA Inc., under cooperative agreement with the NSF. Partial support for NSO is provided by USAF under a Memorandum of Understanding with the NSF. RCA gratefully acknowledges support from the US Air Force Office of Scientific Research, Task PL011.