The interaction of cometary tails with the solar wind


Comets look big, but in reality they are small bodies (their nucleus is typically a few km in size), which have formed from ice and dust (dirty snowballs) during the creation of our solar system 4.5 billion years ago. As the nucleus of a comet approaches the Sun, the ice on its surface layers starts to evaporate. A head, as well as tails of dust and ionized gas with millions of km length develop, leading to the well known cometary appearance. As the magnetized plasma of the solar wind interacts with the ionized (plasma) tail of the comet, long living regular structures of knots and density enhancements are produced.


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High quality consecutive CCD images of the plasma tails of the comets Austin and Hale-Bopp taken with the 0.3 m Skinakas telescope and special filters, have been successfully used to get new significant insight into the relevant physical processes in the cometary tails, as the formation and dynamics of the plasma structures.

The Impact of comet Shoemaker-Levy 9 on Jupiter

jupiter.jpg (64633 bytes) The impact of comet Shoemaker- Levy 9 on planet Jupiter as observed from Skinakas Observatory in July 1994. Three sets of four CCD images are presented, which were obtained through three different filters at subsequent times. Images on the same row were taken thought the same filter, while images on the same column correspond to the same time . The dark spots, resulted from the crash of different comet fragment on the planet appear shifted on subsequent images, due to the planet's rotation.
jupiter_colored.jpg (135699 bytes) True color image of Jupiter impact of comet Shoemaker-Levy 9 created by combining images from three different filters (Ha-continuum, O[III], Hβ)