High def Pluto
Published on Jan 25, 2008 at 4:52 pm.
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Filed under Kuiper belt.
Pluto, one of the largest known Kuiper Belt objects, is the target for the New Horizons spacecraft, launched January 19, 2006. New Horizons will fly past Pluto and its moon Charon in July, 2015. One of New Horizons’ chief instruments is the LORRI (LOng Range Reconnaissance Imager), a telescope with a very highly sensitive CCD. LORRI has a resolution of about one arcsecond. New Horizons is still a very long way from Pluto, yet, it has already been able to acquire Pluto in images taken by the LORRI. Today, in a press release, the mission team at the Johns Hopkins University Applied Physics Laboratory released a high resolution image taken of Pluto by LORRI last October. This is not the first time that New Horizons has seen Pluto. It took a picture a year earlier, in which Pluto was a dot in the image (it is still a dot in the image, just a higher resolution dot).
The important thing here, though, is not that we have a picture with a dot in it. Rather, New Horizons is able to monitor Pluto closely enough to detect variations in its brightness as it rotates. For some time now, observers on the ground as well as the Hubble Telescope have been able to detect variations in brightness as Pluto rotates. This is most certainly due to different parts of Pluto’s surface being different brightnesses. That suggests that Pluto’s surface is not uniform. For whatever reason, be it impact, volcanic, tidal, etc, parts of Pluto’s surface are light and dark. New Horizons is still much too far away from Pluto (still well over 2 billion miles distant) to see any details. However, additional careful monitoring of Pluto’s brightness variations may help us to better map the bright and dark areas. New Horizons will pass Pluto rather quickly, and so it will only be able to carefully study up close a handful of predetermined regions of that body’s surface. Knowing what parts are different brightnesses will allow for planned observations of both bright and dark areas.
-Astroprof
