A&A Supplement Series, Vol. 126, December I 1997, 281-296

Received December 10, 1996; accepted March 18, 1997

The solar disk spectrum between 660 and 1175 Å (first order) obtained by SUMER on SOHO

W. Curdt - U. Feldman - J.M. Laming - K. Wilhelm - U. Schühle - P. Lemaire

Send offprint request: W. Curdt (Curdt@linmpi.mpg.de)
  SFA Inc, 1401 McCormick Drive, Largo, MD 2077Max-Planck-Institut für Aeronomie, D-37191 Katlenburg-Lindau, Germany
  ; Naval Research Laboratory, Washington, D.C., U.S.A.
  SFA Inc, 1401 McCormick Drive, Largo, MD 20774 and Naval Research Laboratory, Washington, D.C., U.S.A.
  Institut d'Astrophysique Spatiale, Unité Mixte, CNRS-Université Paris XI, Bat 121, F-91405 Orsay, France

Abstract:

SUMER - Solar Ultraviolet Measurements of Emitted Radiation - onboard of SOHO - Solar and Heliospheric Observatory - obtained its first spectrum on January 25, 1996 near the north polar limb. The range from 660 Å to 1175 Å which has never before been observed with such a good spectral resolution contains a wealth of spectroscopic details. Identification of about 400 lines in this spectral range is given. We list the wavelengths of identified transitions and provide their absolute peak intensities. General spectral features of the most abundant elements H, He, C, N, O, Ne, Mg, Si, S, Ar, and Fe are described. In this spectral range many density- and temperature-sensitive line pairs are found. It is shown in examples how they can be used as diagnostic tools.

keywords: Sun: atmosphere -- chromosphere -- transition region -- UV radiation

• 1. Introduction
• 2. Instrument and data acquisition
• 3. The line list
• 4. Comments on some of the lines in the list
• 5. Spectroscopic diagnostics with SUMER
• 6. Conclusion
• References