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HST/GHRS Chromospheric line Atlas for Procyon

This page brings you to a short series of ultraviolet spectra of chromospheric lines of Procyon (F5 IV-V) constructed and published by Dr. Brian Wood and colleagues at the University of Colorado (see Wood et al. (1996). MAST is grateful to these investigators for providing their data of a chromospheric spectrum of a near-solar type star.

The F5 IV star Procyon (alpha CMi = HD61421) was chosen it is a nearby star with prominent chromospheric emission lines in its spectrum. These lines appear to be broadened by nonthermal mechanisms and are formed over a range of layers in the chromosphere. Therefore, they exhibit similarities to chromospheric lines in the solar spectrum.

The Wood et al. atlas consists of plots of absolute flux for seven wavelength bands ranging from Si III, Lyman-alpha, and N V lines near 1200 Å to the Mg H/K lines near 2800 Å. The data shortward of 2000 Å were recorded through the Large Science Aperture (LSA) by 4:1 substepping the G160M or G200 (medium resolution) gratings, giving a resolution of 17,000 to 21,000. Longward of 2500 Å the small science aperture (SSA) was used, and substepping was again done, this time with the EB-20 or EB-22 echelle gratings, giving a resolution of about 75,000.

The data given in the table and figures are very similar but not precisely equivalent to those published. The new data provided by Dr. Wood differ from those published in that:   (1) a more recent flux calibration has been employed,   (2) wavelengths are given "old style" (in-air wavelengths longward of 2000 Å),   (3) annotations in the figures give the in-air laboratory wavelengths of the chromospheric lines,   (4) multiple lines of an ion on any one plot arise from the same multiplet,   (5) very weak lines identified in the paper are omitted from our rendition of the plots. In addition, note that the Wood et al. paper details the small redshifts of these features.

Available Data

Copyright Statement: The data presented here were published in the Astrophysical Journal. and appear with the permission of the American Astronomical Society and the authors cited above. Reuse or redistribution of these data is subject to the copyright policies of the American Astronomical Society.