Tombaugh Regio, nicknamed The Heart after its shape,[2][3][4] is the largest bright surface feature of the dwarf planet Pluto.[5][6][7] It is just north of the equator, to the northeast of Cthulhu Regio and to the northwest of Krun Macula, both dark features.[8] Its western lobe is named Sputnik Planum.[9] --Wikipedia