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Sandra Flores

First images of the comet - 0 views

started by Sandra Flores on 09 Jan 15
  • Sandra Flores
    #1 Sandra Flores on 09 Jan 15
     
    Send Mars probes first images of the comet


    On Sunday evening, the comet C / 2013 A1 (Siding Spring) is over flown at a distance of almost 140,000 kilometers on Mars. All active Mars probes have survived the passage of the comet without failures and begun to transmit data, obtained during the pre-flight to Earth. The first images are already available.
    Siding Spring


    Side Spring

    It's not often that a comet passing flies in a distance equal to only about one third of the distance of the Earth from the Moon on a planet that is surrounded by many probes that can observe this passage so close. On Sunday, but this was the case: the comet C / 2013 A1 (Siding Spring) occurred at a distance of almost 140,000 kilometers Mars.

    The currently active Mars probes on the planet and its orbit were prepared for the pre-flight, but it was to take not only a convenient viewing position, but above all the probes do not expose to unnecessary risks. The comet was the Red Planet namely come so close that the experts certainly expected a bombardment of particles from the coma of the comet. The probes were therefore maneuvered into a position in which they were practically in the most dangerous time behind the Mars cover.

    The precautions have apparently paid off all space agencies, operate the probes on the surface or in Mars orbit, reported by now that these work fine even after the pre-flight. Now we have to analyze the data recorded during the passage. You will be transferred to the earth since start of the week - a process that can continue for some days.

    First images of the Martian surface and from Mars orbit lie but before: How could observe the comet with its Panoramic Camera as weak blurred spot in the night sky of Mars Rover Opportunity. "It is very fortunate that this comet has Mars approached so far and we can now examine it with our instruments," said Mark Lemmon of Texas A & M University, who coordinated the observations. "Especially the pictures of Mars rovers give us a human perspective, as they are similar light-sensitive as the human eye."

    On NASA's Mars Reconnaissance Orbiter from Siding Spring there are also pictures from the High Resolution Imaging Science Experiment (HiRISE) already. You have a resolution of only 139 meters per pixel, and make them the first detailed images of a long-period comets are.

    After evaluation of observations with telescopes on Earth, astronomers had assumed a magnitude of the comet nucleus of about one kilometer. The best HiRISE images show, however, that the brightest structure - when they are probably around the core - only has an area of ​​two to three pixels, which would mean that the nucleus of the comet is only about half as large as thought.

    So that the pictures come at all, the camera of the probe had to be very precisely aligned and tracked. These pictures were already twelve days prior to the first approach was made by the Siding Spring, when he was barely recognizable. However, the record showed that the comet was not exactly at the position where he had been expected. Observations on Sunday evening were therefore made with a corrected Orientation. Without these corrections, the comet would possibly not found in the image area that had been targeted by HiRISE during the pre-flight.

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