The Innermost Coma of Comet Hyakutake

The image is a false-colour image reproduction from a short-exposure CCD frame, obtained with the Danish 1.54-metre telescope and the DFOSC instrument with a 2052 x 2052 pix Loral/Lesser CCD. They show the innermost coma of Comet Hyakutake and the pronounced asymmetry of the dust distribution around the nucleus. This photo displays an area of approx. 9.2 x 6.7 arcmin. The typical elongation in the anti-solar direction (at p.a. = 290 deg, i.e. West-North-West) is very pronounced. The asymmetry in the upper-right quadrant (North-West) is also obvious. When moving outwards from the nucleus (located within the black area), the isophotes (curves of equal brightness; particularly well shown by the contrasting colours on these photos) turn anti-clockwise over an angle of about 20 degrees. This effect is caused by the repulsive action on the dust grains by the solar photons.