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

Abstract

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.

Keywords

High Resolution Transition Zone Emission Line Flow Speed Resolution Element 

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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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