April 24, 2019

04.02.10: Pluto Re-imaged.

The most controversial planet (or do you say dwarf planet, or plutoid?) got a new look today. In a press conference, NASA researchers revealed the new “face” of Pluto; a series of images spanning 270 degrees of rotation. To complete these, astronomers scoured 384 images for 4 years using no less than 20 computers. These images were acquired from the Hubble Space Telescope’s Advanced Cameras for Surveys, and span a period from 2002-03. Even under the most favorable conditions, Pluto is a tough target; at around 0.1” arc seconds in size, Pluto only covers only a few pixels even in the best cameras and telescopes. The images are in true color, and present a tan-ish to grey world that is perhaps Mars-like in appearance. This is suggestive of a broad diversity of plutonian topography, and comparisons with the 1994 images show correlations with bright surface features, but also changes that hint at seasonal variations. Specifically, Pluto appears significantly redder and shows a magnitude variation of 0.2 magnitudes, which is surprising over a short 8 year span…Pluto takes 248 years to complete one orbit. Charon, Pluto’s large moon, was a good “color test” as it stayed the same throughout both imaging cycles, lending credence to the idea that the changes throughout were real and not an artifact.

Spectroscopic analysis reveals that Pluto is a dynamic world, covered by frozen methane and fluro-hydrocarbons. In fact, it’s suggested that the world may be a twin to Triton, Neptune’s largest moon. “Certainly, the Kuiper Belt is an amazing place,” such researcher Mike Brown, who laughed at the idea that perhaps Pluto was getting redder in anger at him due to its recent demotion. Hubble’s newly installed WFC3 camera will begin imaging Pluto over a five month period starting April 2010, in anticipation of the New Horizons flyby in 2015. And all this on today, Clyde Tombaugh’s 104th birthday! Expect those astronomy text books to be changing soon…