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Why is Tombaugh Regio called Pluto’s heart-shaped region?
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Pluto
Pluto as observed by the New Horizons spacecraft, July 13, 2015.
Tombaugh Regio is referred to as Pluto’s heart-shaped region because of its distinct visual appearance observed by the New Horizons spacecraft during its 2015 flyby.12
This feature is a large, bright, and smooth plain that dominates one hemisphere of the dwarf planet. The region is characterized by its high reflectivity, with an albedo ranging from 0.8 to 1, which makes it stand out significantly against the darker surrounding terrain. The western portion of this heart-shaped area is known as Sputnik Planitia, a vast basin composed of nitrogen ice.1