3169 Ostro

Lore & Background

3169 Ostro is a member of the Hungaria family, which form the innermost dense concentration of asteroids in the Solar System. It orbits the Sun at a distance of 1.8–2.0 AU once every 2 years and 7 months (950 days), with an eccentricity of 0.07 and an inclination of 25° with respect to the ecliptic.

In the Tholen and SMASS taxonomy, Ostro is classified as a TS-type and Xe-type asteroid, respectively, and has also been characterized as an E-type asteroid. According to the survey carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Ostro measures 4.662 kilometers in diameter and its surface has an outstandingly high albedo of 0.960. The Collaborative Asteroid Lightcurve Link derives an albedo of 0.5152 and a diameter of 5.27 kilometers with an absolute magnitude of 12.73.

In May 2012, a rotational lightcurve of Ostro was obtained from photometric observations by American astronomer Brian Warner. Lightcurve analysis gave a well-defined rotation period of 6.503 hours with a brightness amplitude of 0.79 magnitude (U=3). The minor planet was named after American planetary scientist Steven J. Ostro at the Jet Propulsion Laboratory of the California Institute of Technology, with the approved naming citation published by the Minor Planet Center on 14 April 1987.

Reader's Guide

3169 Ostro is notable primarily for its extremely high albedo of 0.960 as measured by the NEOWISE mission, making it one of the most reflective asteroids known. This high albedo is consistent with its classification as an E-type asteroid, which are typically associated with enstatite-rich surfaces. The asteroid's membership in the Hungaria family places it in the innermost dense concentration of asteroids in the Solar System, providing context for studies of asteroid belt dynamics. The well-defined rotation period of 6.503 hours, determined from photometric observations in 2012, contributes to understanding the physical properties of small bodies. The naming after planetary scientist Steven J. Ostro honors his contributions to radar studies of asteroids and planetary science at JPL. The discrepancy between the NEOWISE diameter (4.662 km) and the Collaborative Asteroid Lightcurve Link value (5.27 km) reflects ongoing uncertainties in asteroid size estimation methods.

Did You Know?

• 3169 Ostro has an outstandingly high albedo of 0.960 according to NEOWISE data.
• It was discovered on 4 June 1981 by American astronomer Edward Bowell.
• The asteroid's rotation period is 6.503 hours, determined from observations in May 2012.