2873 Binzel

Lore & Background

2873 Binzel is a member of the Flora family (402), a giant asteroid family and the largest family of stony asteroids in the main-belt. It orbits the Sun in the inner main belt at a distance of 1.9–2.6 AU once every 3 years and 5 months (1,234 days), with an eccentricity of 0.16 and an inclination of 6° with respect to the ecliptic. The body's observation arc begins with its identification as 1935 KH at the Johannesburg Observatory in 1935, almost 47 years prior to its official discovery observation at Anderson Mesa.

In the SMASS classification, Binzel is a Sq-subtype, which transitions from the common stony S-type asteroids to the less common Q-types. In September 2010, a rotational lightcurve of Binzel was obtained from photometric observations in the R-band by astronomers at the Palomar Transient Factory in California, giving a rotation period of 11.560 hours with a brightness variation of 0.14 magnitude. According to the NEOWISE survey, Binzel measures 6.426 and 7.011 kilometers in diameter with an albedo of 0.2307 and 0.272, respectively. The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.24 and calculates a diameter of 6.48 kilometers based on an absolute magnitude of 13.11.

The asteroid was named after American astronomer Richard Binzel (born 1958) of the University of Texas at Austin, a prolific photometrist who obtained a large number of rotational lightcurves of main-belt asteroids during the 1980s. The official naming citation was prepared by Alan W. Harris and published by the Minor Planet Center on 8 November 1984.

Reader's Guide

2873 Binzel is significant as a binary asteroid system, with its 1.6-kilometer moon discovered in 2019, adding to the understanding of asteroid satellite formation and dynamics. As a member of the Flora family, it provides insights into the composition and evolution of one of the largest stony asteroid families in the main belt. Its Sq-subtype classification bridges the gap between common S-type and rarer Q-type asteroids, offering clues about space weathering processes. The asteroid's rotation period of 11.560 hours, measured by the Palomar Transient Factory, contributes to the database of asteroid lightcurves. The naming after Richard Binzel honors his extensive photometric work, which advanced the study of asteroid rotation and shapes. The multiple diameter estimates from NEOWISE (6.426 and 7.011 km) and the Collaborative Asteroid Lightcurve Link (6.48 km) reflect typical measurement uncertainties in asteroid characterization. Its long observation arc, beginning with a 1935 identification at Johannesburg Observatory, demonstrates the historical depth of asteroid tracking.

Did You Know?

• 2873 Binzel has a 1.6-kilometer minor-planet moon discovered in 2019.
• The asteroid is named after astronomer Richard Binzel, a prolific photometrist of main-belt asteroids.
• Its observation arc began with identification as 1935 KH at Johannesburg Observatory in 1935, nearly 47 years before its official discovery.