Weak infrared molecular lines reveal rapid outflow in cool magnetic sunspot penumbral fibrils

M. J. Penn, Wenda Cao, S. R. Walton, G. A. Chapman, W. Livingston

Research output: Contribution to journalArticle

7 Scopus citations


New imaging spectropolarimetric observations of the Evershed flow in sunspot penumbrae using weak infrared molecular absorption lines are presented. A plane-polar coordinate system in the sunspot frame is defined, allowing averaging of many raw spectra. Molecular lines show Doppler shifts implying typical horizontal outflow speeds of 6 and up to 9 km s-1. The Ti I polarimetric spectra show the same rapid outflow and suggest an average penumbral magnetic field strength of 1400 G. While these observations show Doppler shifts of the entire line profile, the velocities are in better agreement with previous measurements from spectral line asymmetries.

Original languageEnglish (US)
Pages (from-to)L119-L122
JournalAstrophysical Journal
Issue number2 II
StatePublished - Jun 20 2003

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


  • Sun: atmospheric motions
  • Sun: infrared
  • Sunspots
  • Techniques: spectroscopic

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