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HST/GHRS Spectral Atlas of the O9 V Star 10 Lacertae

This page brings you to an ultraviolet atlas of 10 Lacertae constructed by members of the HST Goddard High Resolution Spectrograph (GHRS) scientific development and calibration teams. The star 10 Lac was chosen because it is unique as a bright O (O9V) star exhibiting a very sharp-lined spectrum. As a member of the Lacerta OB1 association, the star is known to have a distance of about 600 pc.

The atlas consists of a number of plots of relative flux versus wavelength over the range 1181 -- 1777 Å. The data were recorded by 4:1 substepping the G160M (medium resolution) grating over an angle corresponding to one pixel at the detector. Each pixel corresponds to a spectral resolution element of about 15 km/s. Fluxes of "continuum pixels" range from 32,000 to 100,000 photon counts across the total spectral range, resulting in a signal-to-noise ratio in excess of 100. The data were recorded over a total time of about 5 hours on 6 November, 1992 through the small science aperture. Note that these observations were done before the installation of the COSTAR corrective optic element. Full details of these observations are given by Brandt et al. (1998).

Taking into account the signal to noise, wavelength range, and the wealth of unblended sharp lines, this is probably the most comprehensive ultraviolet spectral atlas of a hot star published to date. Wavelength identifications were obtained with the aid of a spectral line synthesis codes and model atmosphere data. This has permitted some line blends to be designated. Identifications are given in the atlas for 45 interstellar lines of 17 ions. Stellar wind lines are evident in the form of asymmetric C IV (1548, 1551 Å) and N V (1239, 1243  Å) absorption lines as well as nearly symmetric absorption lines of strong lines of He II, Si IV, and N IV. The atlas is dominated by the presence of over 700 absorption lines of six ionization levels of 16 chemical elements. The interstellar line list and the full list of photospheric lines is given in the accompanying two tables. The "Data" consist of two-column ascii files listing the wavelengths (Ångstroms) and flux (10^-9 ergs cm^-2/s/Å). "ID" list both measured and laboratory wavelengths; the sources for the latter are given in the Brandt et al. paper.

Available Data

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