1160 Illyria, provisional designation 1929 RL, is a stony Maria asteroid from the central regions of the asteroid belt, approximately 13 kilometers in diameter. It was discovered on 9 September 1929, by German astronomer Karl Reinmuth at the Heidelberg Observatory in southwest Germany.[15] The asteroid was named after the ancient region of Illyria, located on the Balkan Peninsula.[3]
Illyria orbits the Sun in the central asteroid belt at a distance of 2.3–2.9 AU once every 4 years and 1 month (1,497 days; semi-major axis of 2.56 AU). Its orbit has an eccentricity of 0.12 and an inclination of 15° with respect to the ecliptic.[1] The body's observation arc begins with a recovery observation at Lowell Observatory in October 1929, three weeks after its official discovery observation at Heidelberg.[15]
Several rotational lightcurves of Illyria have been obtained from photometric observations since 2007.[10][12][13] Lightcurve analysis gave a consolidated rotation period of 4.1025 hours with a brightness amplitude between 0.56 and 0.91 magnitude (U=3).[4][10]
Spin axis
In 2013, an international study also modeled the asteroid's lightcurve from photometric data. It gave a concurring period of 4.10295 hours and determined a partial spin axis of (n.a., 47.0°) in ecliptic coordinates (λ, β).[11]
The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.21, derived from the parent body of the Eunomia family, and calculates a diameter of 13.88 kilometers based on an absolute magnitude of 11.6.[4]
^ abcMasiero, Joseph R.; Grav, T.; Mainzer, A. K.; Nugent, C. R.; Bauer, J. M.; Stevenson, R.; et al. (August 2014). "Main-belt Asteroids with WISE/NEOWISE: Near-infrared Albedos". The Astrophysical Journal. 791 (2): 11. arXiv:1406.6645. Bibcode:2014ApJ...791..121M. doi:10.1088/0004-637X/791/2/121.