Gonggong (dwarf planet)

Lore & Background

Gonggong was discovered on 17 July 2007 by American astronomers Megan Schwamb, Michael Brown, and David Rabinowitz as part of the Palomar Distant Solar System Survey, using the Samuel Oschin telescope at Palomar Observatory. The discovery was announced in January 2009. Initially nicknamed 'Snow White' by Brown due to an assumption of white color, it was later found to be very red, likely due to organic compounds called tholins on its surface. Water ice is also present, hinting at past cryovolcanic activity.

The object is named after Gònggōng, a Chinese water god responsible for chaos, floods, and the tilt of the Earth. The name was chosen in 2019 via an online public poll hosted by the discoverers, winning 46 percent of 280,000 votes. Gonggong has a natural satellite named Xiangliu, which may have caused its slow rotation period of around 22 hours through tidal forces.

Gonggong has a highly eccentric and inclined orbit, ranging from 33–101 AU from the Sun. It is in a 3:10 orbital resonance with Neptune, completing three orbits for every ten of Neptune's. As of 2021, it was about 89 AU from the Sun and moving away at 1.1 km/s.

Reader's Guide

Gonggong's significance lies in its status as a large, distant dwarf planet that provides insights into the outer Solar System's composition and dynamics. Its very red surface, attributed to tholins, and the presence of water ice suggest a complex geological history, possibly including brief cryovolcanic activity. The object's slow rotation, likely influenced by its satellite Xiangliu, contrasts with typical trans-Neptunian objects. Its orbit, highly eccentric and inclined, places it among the scattered disc objects and in a 3:10 resonance with Neptune, offering clues about Neptune's migration and the evolution of the Kuiper belt. The public naming process, which involved an online poll, highlights a modern approach to engaging the public in astronomical nomenclature. Gonggong's large mass may allow it to retain a tenuous methane atmosphere, though it would slowly escape. As one of the farthest known Solar System objects, it helps define the boundaries of our planetary system.

Did You Know?

• Gonggong is similar in size to Pluto's moon Charon, at about 1,230 km in diameter.
• It has a rotation period of around 22 hours, which is slow compared to other trans-Neptunian objects.
• The name Gonggong was chosen via an online public poll in 2019, winning 46 percent of 280,000 votes.