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 Spectro-polarimetry of the comet C/2009 P1 (Garrad).

New observing mode of the 2-channel focal reducer (FoReRo2)

at the 2-m telescope of NAO – Rozhen

 

November 24, 2011

 

During the night of 21/22 October 2011 for the first time a new observing mode of the 2-channel focal reducer (FoReRo2), namely spectro-polarimetry, was used. For this purpose both grisms, working in the red and the blue channel were used together with the Wollaston prism, working in the parallel beam, before splitting the light with a color-divider. In order to avoid overlapping of the spectra, the Wollaston prism has been rotated to split the ordinary and extraordinary beam into a direction perpendicular to the direction of the dispersion.

The first object investigated in this observing mode was comet C/2009 P1 (Garrad). The obtained spectra are presented in the figure. Comparison of these spectra with the picture of the comet taken a few days before with the Schmidt telescope offers an impression about the different chemical elements, molecules and ions, giving their contribution to the different colors and morphological features in the picture. The green circular coma is dominated by emission of C2 and the blue plasma tail corresponds to CO+. In the inner coma close to the nucleus, the contributions of the different emissions and of the continuum (light from the Sun scattered at the dust particles) are mixed, which results in the white “color” of the picture in this region.  Analysis of the results and study of the properties of the comet’s gas and dust environment will be presented soon.

 

For more information contact Galin Borisov, PhD (gborisov@astro.bas.bg).

 

 

Description: Description: Click to see a larger version of the image.

 

 

 

 

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