Optical Interstellar Absorption Along WUPPE Interstellar Polarization Sight Lines

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Session 29 -- General Interstellar Medium
Display presentation, Tuesday, 31, 1994, 9:20-6:30

[29.03] Optical Interstellar Absorption Along WUPPE Interstellar Polarization Sight Lines

Christopher M. Anderson (University of Wisconsin-Madison)

The results of the ultraviolet interstellar polarization program pursued by the Wisconsin Ultraviolet Photo Polarimeter Experiment (WUPPE) during the 1990 December Astro-1 Spacelab mission were discussed by Clayton et.al. 1992, ApJLett,385,L53. There appear to be atleast three distinctly different wavelength dependencies of the ultraviolet polarization. In some directions the so-called Serkowski law which adequately describes the optical and near infrared polarization continues to do so out to the WUPPE limit of 1400$\AA$. However, in two cases the UV polarization is distinctly greater than that which would be predicted by extrapolation of the optical/IR Serkowski fit and in one case there is a suggestion of an enhancement of the polarization across the 2175$\AA$ ultraviolet extinction feature. To investigate environmental factors which might be related to these differences we have observed the northern hemisphere examples of each behavior with the Kitt Peak coude feed telescope, echelle grating and T2KA CCD. Of particular interest are the molecular carbon features and the diffuse interstellar bands which show marked differences between the sight lines. These results will be presented and discussed.

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