[59.03] The Search for Velocity Structure in the Diffuse Interstellar Bands toward Herschel 36

AAS 205th Meeting, 9-13 January 2005
Session 59 ISM: Dust and Molecules
Poster, Tuesday, January 11, 2005, 9:20am-6:30pm, Exhibit Hall

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[59.03] The Search for Velocity Structure in the Diffuse Interstellar Bands toward Herschel 36

M. M. Drosback, T. P. Snow (University of Colorado, CASA), J. A. Thorburn (University of Chicago), S. D. Friedman (Space Telescope Science Institute), L. M. Hobbs (University of Chicago), B. J. McCall (University of Illionois at Urbana-Champaign), B. L. Rachford (Carleton College), P. Sonnentrucker (Johns Hopkins University), D. E. Welty, D. G. York (University of Chicago)

We present results from a search for velocity structure in the Diffuse Interstellar Bands (DIBs) toward the star Herschel 36. This study utilizes high S/N data taken as part of a larger DIB survey using the echelle spectrograph at the Apache Point Observatory 3.5-m telescope. Herschel 36 is a young 07.5 star located in M8 (The Lagoon Nebula), and the line of sight has a large ratio of total to selective extinction indicating the presence of larger than average interstellar dust grains. The atomic sodium and potassium lines in the spectrum indicate the presence of two major absorbing components in the line of sight, separated in velocity by nearly 60 km/s. Using this known velocity separation, we are studying the DIBs present in the spectrum to look for evidence of the same velocity structure in these unidentified, weak absorption bands. If separate velocity components can be seen in the DIBs toward this star, it may be possible to use known physical conditions in the line of sight to place constraints on the nature of some of the diffuse band carriers. We will incoporate into the discussion new FUSE results on the velocity structure of the molecular hydrogen in the line of sight as well.

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