HR: 0830h
AN: SP51B-08    [Abstracts]
TI: The He I 1083 nm line in Coronal Holes, a study with high spectral resolution.
AU: * Malanushenko, O
EM: elena@nso.edu
AF: National Solar Observatory, 950 N. Cherry Ave., Tucson, AZ 85719 United States
AU: Jones, H P
EM: hjones@nso.edu
AF: National Solar Observatory, 950 N. Cherry Ave., Tucson, AZ 85719 United States
AU: Livingston, W
EM: wcl@nso.edu
AF: National Solar Observatory, 950 N. Cherry Ave., Tucson, AZ 85719 United States
AU: Malanushenko, V P
EM: vctorm@noao.edu
AF: Crimean Astrophysicsl Observatory, V.Nauchny, Crimea, 98409 Ukraine
AB: The He 1083 nm line (He), formed in the upper chromosphere, is used for observations of coronal holes (CH) near their origins at the solar surface. Weak He 1083 nm profiles in CHs show some peculiarities such as asymmetry, broadening, and a different ratio between the spectral components. These effects are small so that the influence of disturbing noise and approximations in reduction processes are important for the results. In this research we have used low noise and high spectral resolution observations carried out at the Kitt Peak McMath-Pierce telescope to establish the key characteristics of the He profile in CHs. For accurate reduction we corrected the He profile for spectral blending from water vapor and weak solar lines. We confirm our previous result, based on imaging-spectroscopy data from the Kitt Peak Vacuum Telescope, regarding broadening of the He line in CHs and explain previous instability of CH contrast in our procedure for CH recognition as an influence of hidden photospheric lines.
DE: 7507 Chromosphere
DE: 7511 Coronal holes
DE: 7594 Instruments and techniques
SC: Solar Physics Division - AAS [SP]
MN: 2005 Joint Assembly