As the new comet C/2012 S1 (ISON) approaches its closest distance to the Sun later in November 2013, it is also passing close to the MESSENGER spacecraft now orbiting the innermost planet Mercury. Just this week, the comet has brightened sufficiently to be captured in images by MESSENGER’s wide-angle camera. This figure shows images of ISON for three successive days from November 9 to November 11. The comet appears to brighten each day (top to bottom).
<p>Green circles indicate some of the brighter cataloged background stars in each image; yellow marks bracket the comet. The background stars are fixed in each image from top to bottom, so the motion of the comet relative to the stars is clear in each case. The images have been smoothed slightly to diminish the distracting sharp edges of the pixels.
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MESSENGER is viewing C/2012 S1 from a vantage point that is very different from that of observers on Earth. Comet ISON was approximately 0.75 AU from the Sun and 0.5 AU from MESSENGER when these images were taken.
NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington/Southwest Research Institute
between 9 November 2013 and 11 November 2013 <div style="display: none;">date QS:P,+2013-11-00T00:00:00Z/10,P1319,+2013-11-09T00:00:00Z/11,P1326,+2013-11-11T00:00:00Z/11</div>
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