(184212) 2004 PB112

Lore & Background

2004 PB112 was discovered on 13 August 2004 by American astronomer Marc Buie at the Cerro Tololo Inter-American Observatory in Chile. A first precovery was taken at Cerro Tololo in 2000, extending the body's observation arc by 4 years prior to its official discovery observation. It was numbered (184212) by the Minor Planet Center on 20 April 2008, but as of 2025 it has not been named.

The object orbits the Sun at a distance of 35.3–184.6 AU once every 1153 years and 2 months (421,205 days; semi-major axis of 109.97 AU). Its orbit has a high eccentricity of 0.68 and an inclination of 15° with respect to the ecliptic. It reached perihelion on 5 October 2011. It has been classified as a highly unusual 4:27 resonant trans-Neptunian object, but also simply as a scattered disc object, or SCATNEAR, respectively, by the Deep Ecliptic Survey.

Based on a generic conversion from an absolute magnitude of 7.2, 2004 PB112 measures between 100 and 220 kilometers in diameter. Johnston's Archive estimates a mean diameter of 154 kilometers (96 miles) assuming a typical albedo of 0.09.

Reader's Guide

The significance of (184212) 2004 PB112 lies in its rare 4:27 orbital resonance with Neptune, a high-order ratio that makes it an unusual object among trans-Neptunian bodies. Its classification is disputed: the Deep Ecliptic Survey lists it both as a resonant object and as a scattered disc object (SCATNEAR), reflecting uncertainty in its dynamical status. Discovered by Marc Buie at Cerro Tololo in 2004, with a precovery from 2000, its orbit is highly eccentric (0.68) and inclined (15°), taking it from 35.3 to 184.6 AU from the Sun over a period of about 1153 years. Its estimated diameter of 154 kilometers, based on an assumed albedo of 0.09, places it among the smaller known scattered disc objects. The object was numbered in 2008 but remains unnamed as of 2025, highlighting its status as a relatively obscure but dynamically intriguing member of the outer solar system.

Did You Know?

• 2004 PB112 is in a rare 4:27 orbital resonance with Neptune.
• It was discovered on 13 August 2004 by Marc Buie at Cerro Tololo Inter-American Observatory in Chile.
• A precovery image from 2000 extended its observation arc by 4 years.