Astrophysics and Space Science

, Volume 170, Issue 1–2, pp 135–140 | Cite as

Multiple downflow velocities above sunspotss

  • P. Brekke
  • O. Kjeldseth-Moe
  • G. E. Brueckner
Sun and Sun-Like Stars


Supersonic transition zone downflow appears to be commonly occurring above sunspots. The downflow has been observed in 29 emission lines in the ultra-violet spectrum with the High Resolution Telescope and Spectrograph (HRTS) on two rocket flights and on 5 consecutive days during the Spacelab-2 mission. Spectra from the second rocket flight, contain the most extreme example of downflow, showing speeds up to 180 km s−1 and extending over 60 are sec along the slit. The observations demonstrate the existence of several different distinctive flow speeds within the 1 arc sec resolution element throughout the temperature range 7000–240 000 K.


High Resolution Transition Zone Emission Line Flow Speed Resolution Element 
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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Copyright information

© Kluwer Academic Publishers 1990

Authors and Affiliations

  • P. Brekke
    • 1
  • O. Kjeldseth-Moe
    • 1
  • G. E. Brueckner
    • 2
  1. 1.Institute of Theoretical AstrophysicsUniversity of OsloNorway
  2. 2.E. O. Hulburt Center for Space Research, US Naval Research LaboratoryWashington, DCU.S.A.

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