Abstract
The High Altitude Observatory's white light coronagraph aboard Skylab observed some 110 coronal transients - rapid changes in appearance of the corona - during its 227 days of operation. The longitudes of the origins of these transients were not distributed uniformly around the solar surface (51 of the 100 events observed in seven solar rotations arose from a single quadrant of longitude). Further, the frequency of transient production from each segment of the solar surface was well correlated with the sunspot number and Ca ii plage (area × brightness) index in the segment, rotation by rotation. This correlation implies that transients occur more often above strong photospheric and chromospheric magnetic fields, that is, in regions where the coronal magnetic field is stronger and, perhaps, more variable. This pattern of occurrence is consistent with our belief that the forces propelling transient material outward are, primarily, magnetic. A quantitative relation between transient production from an area and the Zürich sunspot number appropriate to that area is derived, and we speculate that the relation is independent of phase in the solar activity cycle. If true, the Sun may give rise to as many as 100 white light coronal transients per month at solar cycle maximum.
Similar content being viewed by others
References
Bevington, P. R.: 1969, Data Reduction and Error Analysis for the Physical Sciences, McGraw Hill, New York.
Brueckner, G. E.: 1974, in Gordon Newkirk Jr., (ed.), ‘Coronal Disturbances’, IAU Symp. 57, 333.
Brueckner, G. E., Koomen, M. J., and Tousey, R.: 1972, Solar Phys. 24, 254, Frontispiece.
Dulk, G. A., Smerd, S. F., MacQueen, R. M., Gosling, J. T., Magun, A., Stewart, R. T., Sheridan, K. V., Robinson, R. D., and Jacques, S.: 1976, Solar Phys. in press.
Gosling, J. T., Hildner, E., MacQueen, R. M., Munro, R. H., Poland, A. I., and Ross, C. L.: 1974, J. Geophys Res. 79, 4581.
Gosling, J. T., Hildner, E., MacQueen, R. M., Munro, R. H., Poland, A. I., and Ross, C. L.: 1975, Solar Phys. 40, 439.
Gosling, J. T., Hildner, E., MacQueen, R. M., Munro, R. H., Poland, A. I., and Ross, C. L.: 1976, Solar Phys. in press.
Hildner, E., Gosling, J. T., MacQueen, R. M., Munro, R. H., Poland, A. I., and Ross, C. L.: 1975, Solar Phys., 42, 163.
Hildner, E., Gosling, J. T., Hansen, R. T., and Bohlin, J. D.: 1975, Solar Phys. 45, 363.
Howard, R. A., Koomen, M. J., Michels, D. J., Tousey, R., Detwiler, C. R., Roberts, D. E., Seal, R. T., Whitney, J. D., Hansen, R. T., Hansen, S. F., Garcia, C. J., and Yasukawa, E.: 1975, World Data Center A for Solar-Terrestrial Physics. Report UAG-48.
MacQueen, R. M., Gosling, J. T., Hildner, E., Munro, R. H., Poland, A. I., and Ross, C. L.: 1974, Proc. Soc. Photo Optical Instr. Eng. 44, 207.
Munro, R. H., Gosling, J. T., Hildner, E., MacQueen, R. M., Poland, A. I., and Ross, C. L.: 1976, Solar Phys. to be submitted.
Newkirk, G. A. Jr., and Hundhausen, A. J.: 1976, J. Geophys. Res. to be submitted.
NOAA (National Oceanographic and Atmospheric Administration): 1974, Solar-Geophys. Data.
Poland, A. I., and Munro, R. H.: 1976, Astrophys J. to be submitted.
Sheeley, N. R., Jr., Bohlin, J. D., Brueckner, G. E., Purcell, J. D., Scherrer, V. E., and Tousey, R.: 1975a, Solar Phys. 40, 103.
Sheeley, N. R., Jr., Bohlin, J. D., Brueckner, G. E., Purcell, J. D., Scherrer, V. E., and Tousey, R.: 1975b, Astrophys. J. 196, L129.
Stewart, R. T., McCabe, M. K., Koomen, M. J., Hansen, R. T., and Dulk, G. A.: 1974a, Solar Phys. 36, 203.
Stewart, R. T., Howard, R. A., Hansen, S. F., Gergely, T. E., and Kundu, M.: 1974b, Solar Phys. 36, 219.
Tousey, R.: 1973, Space Research XIII, 713.
Tousey, R., Howard, R. A., and Koomen, M. J.: 1974, Bull. Amer. Astron. Soc. 6, 295.
Author information
Authors and Affiliations
Additional information
Currently at Los Alamos Scientific Laboratory, Los Alamos, N.M., U.S.A.
The National Center for Atmospheric Research is sponsored by the National Science Foundation.
Rights and permissions
About this article
Cite this article
Hildner, E., Gosling, J.T., MacQueen, R.M. et al. Frequency of coronal transients and solar activity. Sol Phys 48, 127–135 (1976). https://doi.org/10.1007/BF00153339
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF00153339