2074 Shoemaker

Lore & Background

2074 Shoemaker was discovered on 17 October 1974 by astronomer Eleanor Helin at the Palomar Observatory. It is a bright member of the dynamical Hungaria group, orbiting the Sun in the inner main-belt at a distance of 1.7–1.9 AU once every 2 years and 5 months (882 days). Its orbit has an eccentricity of 0.08 and an inclination of 30° with respect to the ecliptic. With a perihelion of 1.6521 AU, it crosses the orbit of Mars at 1.666 AU, making it a Mars-crossing asteroid. The body's observation arc begins with a precovery taken at Palomar in April 1954, more than 20 years prior to its official discovery. In the SMASS classification, Shoemaker is an Sa-subtype, transitioning from common stony S-type asteroids to A-type asteroids. Several rotational lightcurves were obtained by American astronomer Brian Warner at his Palmer Divide Observatory and CS3-Station, giving a well-defined rotation period of 2.5328 hours with a brightness amplitude of 0.13 magnitude. In October 2003, photometric observations by Robert D. Stephens gave a long rotation period of 57.02 hours; after re-measuring with newer software, two mutual occultation and eclipsing events were found, indicating it might be a synchronous binary asteroid with a minor-planet moon orbiting every 55 hours. Observations in 2010 gave an orbital period of 27.39 hours for the secondary, while 2015 observations at Etscorn Campus Observatory did not mention any mutual events. In June 2017, Warner measured a rotation period of 2.5331±0.0002 hours and an orbital period for the secondary of 44.28 hours. The binary nature remains unconfirmed. According to the NEOWISE mission, Shoemaker measures 3.18 and 3.22 kilometers in diameter with an albedo between 0.41 and 0.52. The Collaborative Asteroid Lightcurve Link assumes a standard albedo of 0.20 and calculates a diameter of 4.93 kilometers based on an absolute magnitude of 13.9. The minor planet was named by the discoverer after American astronomer Eugene Shoemaker, known for his work on impact craters and his role in the lunar Ranger, Surveyor and Apollo programs. The naming was also proposed by Brian G. Marsden, and the official citation was published on 1 November 1978.

Reader's Guide

2074 Shoemaker holds significance as a suspected synchronous binary asteroid, a rare configuration among small bodies. Its potential binary nature, suggested by mutual occultation and eclipsing events observed in 2003 and later measurements, remains unconfirmed despite multiple observation campaigns. This uncertainty highlights the challenges in characterizing small, distant objects. The asteroid's membership in the Hungaria group, the innermost dense concentration of asteroids, and its classification as a Mars-crosser place it in a dynamically interesting region. Its stony Sa-type composition, bridging S-type and A-type asteroids, adds to its scientific value. The naming after Eugene Shoemaker honors a pioneering figure in planetary science, linking the asteroid to his legacy in impact crater studies and lunar exploration. The discovery by Eleanor Helin and the involvement of Brian Warner and others in its photometric analysis underscore the collaborative nature of asteroid research. The NEOWISE-derived diameter and albedo provide key physical parameters, while the discrepancy with the Lightcurve Link's estimate reflects differing assumptions about surface properties.

Did You Know?

• 2074 Shoemaker was discovered by Eleanor Helin at Palomar Observatory on 17 October 1974.
• It is a suspected synchronous binary asteroid, but its binary nature remains unconfirmed.
• It was named after Eugene Shoemaker, known for his work on impact craters and the Shoemaker–Levy 9 comet.