Evidence of multiple layers of haze in the atmosphere of Pluto and the discovery that the dwarf planet is both larger and more ice-rich than previously thought were among the findings reported by the New Horizons team in the October 16 edition of the journal Science.
In the study, first author Alan Stern from the Southwest Research Institute (SwRI), the principal investigator for the New Horizons mission, and his colleagues also detailed that Pluto was home to a wide variety of landforms and terrain ages, as well as an array of different compositions and colors. They also found evidence for a water-ice rich crust and layers of atmospheric haze.
The publication of the paper comes just three months after the NASA probe’s historic July flyby of the Pluto system, during which time it passed within 8,507 miles (13,691 kilometers) from the dwarf planet’s surface at its closest approach. More than 150 New Horizons scientists and NASA personnel were credited as authors of the new study, according to the SwRI.
“The New Horizons mission completes our initial reconnaissance of the solar system, giving humanity our first look at this fascinating world and its system of moons,” Jim Green, director of planetary science at NASA HQ, said in a statement. “[It] is not only writing the textbook on the Pluto system, it’s serving to inspire current and future generations to keep exploring.”
Dwarf planet and its moons home to many surprises
Among the findings reported in the newly published paper is the discovery that Pluto’s surface has a substantial amount of variation in terms of color, composition and surface reflectivity (or albedo). Stern and his colleagues also found evidence of tectonic extension, surface volatile ice convection, possible wind streaks, glacial flow and geologically young surface units.
In addition to the haze layer, analysis of Pluto’s atmosphere found that it was highly extended, with trace amounts of hydrocarbons and a surface pressure of about 10 microbars. The dwarf planet and its moon Charon were found to differ by less than 10 percent, which the authors said suggested that their precursor bodies were at most only moderately differentiated pre-collision.
This would have “profound implications” for the timing, duration and accretion mechanisms of the ancestral Kuiper Belt, the researchers wrote. They also found possible evidence that Charon has a heterogeneous crustal composition due to unusual dark terrain in its north pole, and noted that New Horizons collected the first-ever measurements of the sizes and albedo of Pluto’s tiny moons Nix and Hydra. The authors added that no new moon were located in the system.
“The Pluto system surprised us in many ways, most notably teaching us that small planets can remain active billions of years after their formation,” Stern said, adding that he and his fellow researchers also learned “important lessons by the unexpected degree of geological complexity that both Pluto and its large moon Charon display.”
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Feature Image: This high-resolution image captured by NASA’s New Horizons spacecraft combines blue, red and infrared images taken by the Ralph/Multispectral Visual Imaging Camera (MVIC). Pluto’s surface shows a remarkable range of subtle colors, digitally enhanced in this view to a rainbow of pale blues, yellows, oranges, and deep reds. The bright expanse is the western lobe of the “heart,” informally known as Tombaugh Regio. The lobe, informally called Sputnik Planum, has been found to be rich in nitrogen, carbon monoxide, and methane ices. Pluto’s diameter is 1,473 miles (2,372 kilometers). (Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute)
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