TRES Survey of Variable Diffuse Interstellar Bands

Abstract

Diffuse interstellar bands (DIBs) are absorption features commonly observed in optical/near-infrared spectra of stars and thought to be associated with polyatomic molecules that comprise a significant reservoir of organic material in the universe. However, the central wavelengths of almost all DIBs do not correspond with electronic transitions of known atomic or molecular species and the specific physical nature of their carriers remains inconclusive despite decades of observational, theoretical, and experimental research. It is well established that DIB carriers are located in the interstellar medium, but the recent discovery of time-varying DIBs in the spectra of the extragalactic supernova SN2012ap suggests that some may be created in massive star environments. Here we report evidence of short time-scale (10-60 d) changes in DIB absorption line substructure toward 3 of 17 massive stars observed as part of a pathfinder survey of variable DIBs conducted with the 1.5-m Tillinghast telescope and Tillinghast Reflector Echelle Spectrograph (TRES) at Fred L. Whipple Observatory. The detections are made in high-resolution optical spectra (R = 44000) having signal-to-noise ratios of 5-15 around the 5797 and 6614 angstrom features, and are considered significant but requiring further investigation. We find that these changes are potentially consistent with interactions between stellar winds and DIB carriers in close proximity. Our findings motivate a larger survey to further characterize these variations and may establish a powerful new method for probing the poorly understood physical characteristics of DIB carriers.

11 pages, 7 figures, accepted for publication in MNRAS

References in corpus (16)

• The Galactic WN stars: Spectral analyses with line-blanketed model atmospheres versus stellar evolution models with and without rotation
• Toward Complete Statistics of Massive Binary Stars: Penultimate Results from the Cygnus OB2 Radial Velocity Survey
• The Diffuse Interstellar Bands: A Major Problem in Astronomical Spectroscopy
• Studies of the Diffuse Interstellar Bands. III. HD 183143
• The Massive Star Population of Cygnus OB2
• Infrared Diffuse Interstellar Bands in the Galactic Centre Region
• Anomalous Diffuse Interstellar Bands in the Spectrum of Herschel 36. II. Analysis of Radiatively Excited CH+, CH, and DIBs
• Anomalous Diffuse Interstellar Bands in the Spectrum of Herschel 36. I. Observations of Rotationally Excited CH and CH+ Absorption and Strong, Extended Redward Wings on Several DIBs
• A search for diffuse bands in the circumstellar envelopes of post-AGB stars
• New Herbig Ae/Be stars confirmed via high-resolution optical spectroscopy
• Interaction Between The Broad-lined Type Ic Supernova 2012ap and Carriers of Diffuse Interstellar Bands
• A search for diffuse bands in fullerene planetary nebulae: evidence of diffuse circumstellar bands
• Small-scale structure in the interstellar medium: time-varying interstellar absorption towards κ Velorum
• The $\lambda$6614 diffuse interstellar absorption band: evidence for internal excitation of the carrier
• Star clusters in the Sh2-132 complex: clues about the connection between embedded and open clusters
• A Chandra Observation of the Eclipsing Wolf-Rayet Binary CQ Cep

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