Unusually Weak Diffuse Interstellar Bands toward HD 62542

Abstract

As part of an extensive survey of diffuse interstellar bands (DIBs), we have obtained optical spectra of the moderately reddened B5V star HD 62542, which is known to have an unusual UV extinction curve of the type usually identified with dark clouds. The typically strongest of the commonly catalogued DIBs covered by the spectra -- those at 5780, 5797, 6270, 6284, and 6614 A -- are essentially absent in this line of sight, in marked contrast with other lines of sight of similar reddening. We compare the HD 62542 line of sight with others exhibiting a range of extinction properties and molecular abundances and interpret the weakness of the DIBs as an extreme case of deficient DIB formation in a dense cloud whose more diffuse outer layers have been stripped away. We comment on the challenges these observations pose for identifying the carriers of the diffuse bands.

20 pages, 4 figures; aastex; accepted by ApJ

References in corpus (2)

• Observations of H3+ in the Diffuse Interstellar Medium
• Rejection of the C7- Diffuse Interstellar Band Hypothesis

Cited by in corpus (18)

• A FUSE Survey of Interstellar Molecular Hydrogen in Translucent Clouds
• The Diffuse Interstellar Bands: A Major Problem in Astronomical Spectroscopy
• VLT/UVES Observations of Interstellar Molecules and Diffuse Bands in the Magellanic Clouds
• Spectroscopic survey of the Galaxy with Gaia I. Design and performance of the Radial Velocity Spectrometer
• The Apache Point Observatory Catalog of Optical Diffuse Interstellar Bands
• Observations of rotationally resolved C3 in translucent sight lines
• Diffuse Interstellar Bands vs. Known Atomic and Molecular Species in the Interstellar Medium of M82 toward SN 2014J
• A Tale of Two Mysteries in Interstellar Astrophysics: The 2175 Angstrom Extinction Bump and Diffuse Interstellar Bands
• New Insights on Interstellar Gas-Phase Iron
• The Behavior of Selected Diffuse Interstellar Bands with Molecular Fraction in Diffuse Atomic and Molecular Clouds
• Near infrared diffuse interstellar bands toward the Cygnus OB2 association
• Diffuse Interstellar Bands and the Ultraviolet Extinction Curves: The Missing Link Revisited
• HD 62542: Probing the Bare, Dense Core of a Translucent Interstellar Cloud
• Diffuse interstellar bands in the HII region M17: Insights into their relation with the total-to-selective visual extinction $R_V$
• Updated extraction of the APOGEE 1.5273 μm diffuse interstellar band: a Planck view on the carrier depletion in dense cores
• The 15273 Å diffuse interstellar band in the dark cloud Barnard 68
• Diffuse Interstellar Bands: How Are They Related to Known Gas-Phase Constituents of the ISM?
• On the relationship between the continuum of interstellar extinction curves, the 2200 Å bump, and the diffuse interstellar bands