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Solar Physics

, Volume 7, Issue 3, pp 351–365 | Cite as

Chromospheric inhomogeneities in sunspot umbrae

  • Jacques M. Beckers
  • Paul E. Tallant
Article
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Abstract

The properties of rapidly changing inhomogeneities visible in the H and K lines above sunspot umbrae are described. We find as properties for these ‘Umbral Flashes’:
  1. (a)

    A lifetime of 50 sec. The light curve is asymmetrical, the increase is faster than the decrease in brightness.

     
  2. (b)

    A diameter ranging from the resolution limit up to 2000 km.

     
  3. (c)

    A tendency to repeat every 145 sec.

     
  4. (d)

    A ‘proper motion’ of 40 km/sec generally directed towards the penumbra.

     
  5. (e)

    A Doppler shift of 6 km/sec.

     
  6. (f)

    A magnetic field of 2100 G.

     
  7. (g)

    A decrease in this field of 12 G/sec. This decrease is probably related to the flash motion.

     
  8. (h)

    At any instant an average of 3–5 flashes in a medium-sized umbra. A weak feature often persists in the umbra after the flash. This post-flash structure initially shows a blue shift, but 100–120 sec after the flash, it shows a rapid red shift just before the flash repeats.

     

Keywords

Magnetic Field Blue Shift Light Curve Doppler Shift Resolution Limit 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
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References

  1. Bappu, M. K. V. and Sivaraman, K. R.: 1968, in I.A.U. Symposium No. 35, p. 247.Google Scholar
  2. Beckers, J. M.: 1964, Dissertation, Utrecht (= AFCRL Environmental Research Paper No. 75).Google Scholar
  3. Beckers, J. M. and Schröter, E. H. 1968a, Solar Phys. 4, 142.Google Scholar
  4. Beckers, J. M. and Schröter, E. H. 1968b, Solar Phys. 4, 303.Google Scholar
  5. Beckers, J. M. and Schröter, E. H. 1969, Solar Phys. (in preparation).Google Scholar
  6. Bray, R. J. and Loughhead, R. E.: 1964, Sunspots (The International Astrophysics Series, Vol. 7), Chapman and Hall, London.Google Scholar
  7. Bumba, V.: 1958, Observatory 78, 33.Google Scholar
  8. Bumba, V.: 1960, Izv. Krymsk. Astrofiz. Observ. 23, 212.Google Scholar
  9. Engvold, O.: 1967a, Solar Phys. 2, 234.Google Scholar
  10. Engvold, O.: 1967b, Astrophys. Norv. 10, 173.Google Scholar
  11. Feosilov, P. P.: 1961, The Physical Basis of Polarized Emission, Consultants Bureau, New York.Google Scholar
  12. Howard, R., Tanenbaum, A. S., and Wilcox, J. M.: 1968, Solar Phys. 4, 286.Google Scholar
  13. Livshitz, M. A., Obridko, V. N., and Pikel'ner, S. B.: 1967, Soviet Astron. 10, 909.Google Scholar
  14. Maltby, P.: 1968, Solar Phys. 5, 3.Google Scholar
  15. Mohler, O. C.: 1960, Astron. J. 65, 55.Google Scholar
  16. Mustel, E. R.: 1955, Izv. Krymsk. Astrofiz. Observ. 13, 96.Google Scholar
  17. Mustel, E. R. and Tsap, T. T.: 1958, Izv. Krysmk. Astrofiz. Observ. 20, 74.Google Scholar
  18. Mustel, E. R. and Tsap, T. T.: 1960, Izv. Krymsk. Astrofiz. Observ. 22, 75.Google Scholar
  19. Paciorek, J.: 1965, Third Consultation on Solar Physics and Hydrodynamics, Czechoslovak Acad. Sci. Astron. Institute Publ. 51, 69.Google Scholar
  20. Ringness, T. S. and Jensen, E.: 1961, Astrophys. Norv. 7, 99.Google Scholar
  21. St. John, E.: 1911, Astrophys. J. 34, 131.Google Scholar
  22. Smith, E. v. P.: 1960, Astrophys. J. 132, 202.Google Scholar
  23. Suemoto, Z.: 1951, Publ. Astron. Soc. Japan 2, 137.Google Scholar
  24. Tallant, P. E.: 1969, Solar Phys. (in preparation).Google Scholar
  25. Zwaan, C.: 1968, Ann. Rev. Astron. Astrophys. 6, 135.Google Scholar

Copyright information

© D. Reidel Publishing Company 1969

Authors and Affiliations

  • Jacques M. Beckers
    • 1
  • Paul E. Tallant
    • 1
  1. 1.Sacramento Peak Observatory, Air Force Cambridge Research LaboratoriesSunspotU.S.A.

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