Safronov Regio

Safronov Regio

Enhanced color view of Safronov Regio's western border with Sputnik Planitia
Location	Pluto
Coordinates	13°22′S 150°31′W / 13.36°S 150.51°W / -13.36; -150.51[1]
Diameter	~740 km (460 mi)[1]
Discoverer	New Horizons
Eponym	Viktor Safronov

Safronov Regio (formerly Krun Macula) is the westernmost of the "Brass Knuckles", a series of equatorial dark regions on Pluto.

Safronov Regio was first observed as the New Horizons spacecraft approached Pluto and its system of moons. As Pluto rotated, a series of equatorial dark regions were observed and informally nicknamed the Brass Knuckles,^[2] with Safronov Regio being the westermost of the dark regions. It was initially informally named Krun Macula after Krun, the greatest of the five Mandaean lords of the underworld.^[3][4] However, the International Astronomical Union (IAU) instead officially approved the name Safronov Regio in honor of Russian astronomer Viktor Safronov, an early proponent of the planetesimal hypothesis for Solar System formation. The name was approved on 22 September 2023.^[1]

Safronov Regio is the third largest equatorial dark region on Pluto, after Belton Regio and Harrington Regio. It extends nearly to 180 degrees longitude, the Plutonian longitude opposite Charon.

Krun Macula is the name of one of the ship of the character Pluto in Heaven Will Be Mine, a 2018 visual novel.^[5]