STUDIES OF THE DIFFUSE INTERSTELLAR BANDS. III. HD 183143

Journal Article · Sun Nov 01 04:00:00 EST 2009 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/705/1/32· OSTI ID:21378419

Hobbs, L M; Thorburn, J A ^[1]; York, D G; Bishof, M; Oka, T ^[2]; Snow, T P ^[3]; Friedman, S D ^[4]; McCall, B J ^[5]; Rachford, B ^[6]; Sonnentrucker, P ^[7]; Welty, D E ^[8]

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1. University of Chicago, Yerkes Observatory, Williams Bay, WI 53191 (United States)
2. Department of Astronomy and Astrophysics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States)
3. University of Colorado, CASA-Campus Box 389, Boulder, CO 80309 (United States)
4. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
5. Departments of Chemistry and Astronomy, University of Illinois, 600 South Mathews Avenue, Urbana, IL 61801 (United States)
6. Department of Physics, Embry-Riddle Aeronautical University, 3700 Willow Creek Road, Prescott, AZ 86301 (United States)
7. Department of Physics and Astronomy, Johns Hopkins University, 34th and Charles Streets, Baltimore, MD21218 (United States)
8. Department of Astronomy, University of Illinois, 1002 W. Green St., Urbana, IL 61801 (United States)

Echelle spectra of HD 183143 [B7Iae, E(B - V) = 1.27] were obtained on three nights, at a resolving power R = 38,000 and with a signal-to-noise ratio approx 1000 at 6400 A in the final, combined spectrum. A catalog is presented of 414 diffuse interstellar bands (DIBs) measured between 3900 and 8100 A in this spectrum. The central wavelengths, the widths (FWHM), and the equivalent widths of nearly all of the bands are tabulated, along with the minimum uncertainties in the latter. Among the 414 bands, 135 (or 33%) were not reported in four previous, modern surveys of the DIBs in the spectra of various stars, including HD 183143. The principal result of this study is that the great majority of the bands in the catalog are very weak and fairly narrow. Typical equivalent widths amount to a few mA, and the bandwidths (FWHM) are most often near 0.7 A. No preferred wavenumber spacings among the 414 bands are identified which could provide clues to the identities of the large molecules thought to cause the DIBs. At generally comparable detection limits in both spectra, the population of DIBs observed toward HD 183143 is systematically redder, broader, and stronger than that seen toward HD 204827 (Paper II). In addition, interstellar lines of C{sub 2} molecules have not been detected toward HD 183143, while a very high value of N(C{sub 2})/E(B - V) is observed toward HD 204827. Therefore, either the abundances of the large molecules presumed to give rise to the DIBs, or the physical conditions in the absorbing clouds, or both, must differ significantly between the two cases.

• OSTI ID: 21378419
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 705; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABUNDANCE
CLOUDS
DIMENSIONLESS NUMBERS
SIGNAL-TO-NOISE RATIO
SPECTRA
STARS