TRES Survey of Variable Diffuse Interstellar Bands
  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.
