Special Issue: Rosetta Begins Its Comet Tale (7 of 18) (IMAGE)

American Association for the Advancement of Science (AAAS)

Special Issue: Rosetta Begins Its Comet Tale (7 of 18)

Caption

1. The comet approaches the sun. 2. Water molecules sublimate from the comet as it thaws. 3. The water molecules are ionized by ultraviolet light from the sun. 4. Newborn ions are accelerated by the solar wind electric field and can be detected by the RPC-ICA instrument. 5. The solar wind accelerates the water ions in one direction, but is itself deflected in the opposite direction. 6. In due time sharp boundaries will form, shielding the comet atmosphere from direct interaction with the solar wind. This is a well-known situation observed at active comets and planets. This material relates to a paper that appeared in the Jan. 23, 2015, issue of Science, published by AAAS. The paper, by H. Nilsson at Swedish Institute of Space Physics in Kiruna, Sweden, and colleagues was titled, " Birth of a comet magnetosphere: A spring of water ions."

Credit

[Credit: Illustration by Etienne Behar, comet shape model ESA/Rosetta/NAVCAM]

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