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Solar EUV Rocket Telescope and Spectrograph (SERTS) Observations of Fe XII Emission Lines

Published online by Cambridge University Press:  12 April 2016

F.P. Keenan ,
R.J. Thomas ,
W.M. Neupert ,
V.J. Foster ,
C.J. Greer  and
S.S. Tayal
F.P. Keenan
Affiliation:
Department of Pure and Applied Physics, The Queen’s University of Belfast, Belfast BT7 INN, N.Ireland
R.J. Thomas
Affiliation:
Laboratory for Astronomy and Solar Physics, Code 680, NASA/Goddard Space Flight Center, Greenbelt, MD 20771, USA
W.M. Neupert
Affiliation:
Laboratory for Astronomy and Solar Physics, Code 680, NASA/Goddard Space Flight Center, Greenbelt, MD 20771, USA
V.J. Foster
Affiliation:
Department of Pure and Applied Physics, The Queen’s University of Belfast, Belfast BT7 INN, N.Ireland
C.J. Greer
Affiliation:
Department of Pure and Applied Physics, The Queen’s University of Belfast, Belfast BT7 INN, N.Ireland
S.S. Tayal
Affiliation:
Department of Physics and Center for Theoretical Studies of Physical Systems, Clark Atlanta University, Atlanta, GA 30314, USA

Abstract.

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Theoretical electron density sensitive emission line ratios involving transitions in the 186–383 Å wavelength range are compared with observational data for a solar active region and a subflare, obtained by the Solar EUV Rocket Telescope and Spectrograph (SERTS). Electron densities derived from the majority of the ratios are consistent with one another, and are also in good agreement with the values of density estimated from diagnostic lines in other species formed at similar temperatures to Fe XII. These results provide observational support for the general accuracy of the diagnostic calculations. In addition, our analysis indicates that a line at 283.70 Å in the active region spectrum is the 3s23p32D3/2−3s3p42P1/2 transition in Fe XII, the first time (to the best of our knowledge) that this line has been identified in the solar spectrum. Several of the line ratios considered are predicted to be relatively insensitive to the adopted electron temperature and density, and the generally good agreement found between theory and observation for these provides evidence for the reliability of the SERTS instrument calibration. The application of the Fe XII diagnostics to EUVE observations of the F5 subgiant Procyon is briefly discussed.

Type
XII. The Solar/Stellar Connection in the EUV
Information
International Astronomical Union Colloquium , Volume 152: Astrophysics in the Extreme Ultraviolet , 1996 , pp. 531 - 536
Copyright
Copyright © Kluwer 1996

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