(5646) 1990 TR

(5646) 1990 TR is a probable rare-type binary asteroid classified as near-Earth object of the Amor group, approximately 2.3 kilometers in diameter. It was discovered on 11 October 1990, by Japanese astronomers Seiji Ueda and Hiroshi Kaneda at Kushiro Observatory near Kushiro, in eastern Hokkaido, Japan.

(5646) 1990 TR

(5646) 1990 TR is a probable rare-type binary asteroid classified as a near-Earth object of the Amor group, with an approximate diameter of 2.3 kilometers. Discovered on 11 October 1990 by Japanese astronomers Seiji Ueda and Hiroshi Kaneda at the Kushiro Observatory in eastern Hokkaido, Japan, it has gained interest due to its unique characteristics.

Orbit

The asteroid orbits the Sun at a distance of 1.2–3.1 AU, completing an orbit every 3 years and 2 months (1,147 days). It features an orbit with an eccentricity of 0.44 and an inclination of 8° relative to the ecliptic. Its observation arc began with its first recorded observation at the Siding Spring Observatory five months prior to its official discovery.

Lightcurve

In December 2012, the most reliable rotational lightcurve was captured by American astronomer Brian Warner at his Palmer Divide Observatory in Colorado. Analysis of the lightcurve indicated a rotation period of 3.1999 hours with a brightness variation of 0.12 magnitude (U=3). Additionally, photometric observations suggested a period of 19.47 hours for a probable asteroid moon, with a diameter-ratio of 0.18±0.02, estimating the moon’s diameter to be approximately 400 meters.

Diameter and Albedo

Surveys conducted by the Spitzer Space Telescope and NASA’s Wide-field Infrared Survey Explorer (NEOWISE mission) provide measurements for the asteroid’s diameter, estimating between 2.03 and 2.723 kilometers. The asteroid’s surface has an albedo ranging from 0.19 to 0.66. The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.18, leading to a derived diameter of 2.3 kilometers based on its absolute magnitude of 15.67.

References

  • Lightcurve plot of (5646) 1990 TR, Palmer Divide Observatory, B. D. Warner (2012)
  • Asteroids with Satellites, Robert Johnston, johnstonsarchive.net
  • Asteroid Lightcurve Database (LCDB), query form
  • Dictionary of Minor Planet Names, Google Books
  • Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend
  • (5646) 1990 TR at NeoDyS-2, Near Earth Objects—Dynamic Site
  • (5646) 1990 TR at ESA–space situational awareness
  • (5646) 1990 TR at the JPL Small-Body Database