The comet C/2009 R1 (McNaught)
June 18, 2010
In the early morning hours of 17 June 2010 Comet C/2009 R1 (McNaught) was slightly above the north-east horizon, in the constellation Perseus. Astronomers in the National astronomical observatory – Rozhen obtained images and spectra of the comet with the 2-meter telescope equipped with the 2-channel focal reducer (FoReRo2). At the same time large scale images were obtained with the 60-cm telescope.
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Image of the comet in the red spectral region. East is left, North - up. The size of the image is 7.5x7.5 arc minutes, which corresponds to about 375 000 km at the comet in the moment of the observation. In the upper-right part of the image, in the anti-solar direction, the plasma tail is visible. In this spectral region it is dominated by water ions. The near nucleus region is dominated by the dust coma, which reflects the solar radiation.
The spectrum of the comet in the region between 360 and 700 nm. The spectrum is formed from two separate images obtained simultaneously in the blue and the red channels of the FoReRo2, using so called long slit. This method gives opportunity to determine at once the spatial and the spectral distribution of the comet gas and dust. The upper part of the figure shows part of the spectrum centered at the comet nucleus and corresponding to about 100000 km in vertical direction. In the lower part of the figure the average spectrum of the comet, obtained by summing the spectra at different distances from the nucleus (along the height of the slit), is presented. The most typical emissions in the blue region are the bright cyan (CN) and less bright triatomic carbon molecule (C3). In the red channel dominate the emissions of diatomic carbon molecule (C2), amine (NH2) and the forbidden line of the oxygen [OI].
For more information please contact Dr. Galin Borisov (gborisov@astro.bas.bg).
Image of C/2009 R1 (McNaught) obtained with the 60-sm telescope of NAO-Rozhen. The size of the field is 17 x 17 arcminutes and contains only a part of the comet’s tail. Image: Sunay Ibryamov, astronomy student in the University of Shumen “Ep. K. Preslavski”, e-mail s.ibryamov@abv.bg.