E. G. Rivera-Valentin, P. A. Taylor, A. Virkki, and B. Aponte-Hernandez, Arecibo Observatory, Universities Space Research Association, report that Arecibo (2380 MHz, 12.6 cm) delay-Doppler radar images obtained on 2017 Jan. 20 and 23 reveal that the near-earth minor planet (163693) is a binary system. Visible range extents of the components in images with a resolution of 150 m/pixel suggest a primary up to 4.8 +/- 0.5 km in diameter and a secondary 1.0 +/- 0.3 km in diameter. The primary is possibly elongated and very angular in shape. On Jan. 20, the system was observed near maximum separation in delay (range), suggesting a mutual-orbit scale of at least 5.7 km. On Jan. 23, the system was observed near maximum separation in Doppler frequency, suggesting an orbital period of roughly 16 hours. A preliminary circular orbit fit finds a (projected) semimajor axis of 6 km and a period of 15.5 hours.
Central Bureau Electronic Telegrams
- Pub Date:
- January 2017