M. Galiazzo, C. de la Fuente Marcos, R. de la Fuente Marcos, G. Carraro, M. Maris, M. Montalto

Abstract
Both Centaurs and trans-Neptunian objects (TNOs) are minor bodies found in the outer Solar System. Centaurs are a transient population that moves between the orbits of Jupiter and Neptune, and they probably diffused out of the TNOs. TNOs move mainly beyond Neptune. Some of these objects display episodic cometary behaviour; a few percent of them are known to host binary companions. Here, we study the light-curves of two Centaurs—2060 Chiron (1977 UB) and 10199 Chariklo (1997 CU₂₆)—and three TNOs—38628 Huya (2000 EB₁₇₃), 28978 Ixion (2001 KX₇₆), and 90482 Orcus (2004 DW)—and the colours of the Centaurs and Huya. Precise, ~1%, R-band absolute CCD photometry of these minor bodies acquired between 2006 and 2011 is presented; the new data are used to investigate the rotation rate of these objects. The colours of the Centaurs and Huya are determined using BVRI photometry. The point spread function of the five minor bodies is analysed, searching for signs of a coma or close companions. Astrometry is also discussed. A periodogram analysis of the light-curves of these objects gives the following rotational periods: 5.5±0.4 h for Chiron, 7.0± 0.6 h for Chariklo, 4.45±0.07 h for Huya, 12.4±0.3 h for Ixion, and 11.9±0.5 h for Orcus. The colour indices of Chiron are found to be B-V=0.53±0.05, V-R=0.37±0.08, and R-I=0.36±0.15. The values computed for Chariklo are V-R=0.62±0.07 and R-I=0.61±0.07. For Huya, we find V-R=0.58±0.09 and R-I=0.64±0.20. Our rotation periods are similar to and our colour values are consistent with those already published for these objects. We find very low levels of cometary activity (if any) and no sign of close or wide binary companions for these minor bodies.

Keywords
Minor planets, asteroids: individual: 2060 Chiron (1977 UB); Minor planets, asteroids: individual: 10199 Chariklo (1997 CU₂₆); Minor planets, asteroids: individual: 38628 Huya (2000 EB₁₇₃); ...

Astrophysics and Space Science
Volume 361, Issue 212
2016 July

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