Shape model and spin state of non-principal axis rotator (5247) Krylov
Duffard, R.; Marciniak, A.; Ďurech, J.; Erece, O.; Lehký, M.; Kim, M. -J.; Choi, Y. -J.; Kaplan, M.; Galád, A.; Lee, H. -J.; Moon, H. -K.; Kim, C. -H.; Pray, D.; Gajdoš, Š.; Világi, J.
South Korea, Czech Republic, Slovakia, United States, Poland, Turkey, Spain
Abstract
Context. The study of non-principal axis (NPA) rotators can provide important clues to the evolution of the spin state of asteroids. However, very few studies to date have focused on NPA-rotating main belt asteroids (MBAs). One MBA known to be in an excited rotation state is asteroid (5247) Krylov.
Aims: By using disk-integrated photometric data, we construct a physical model of (5247) Krylov including shape and spin state.
Methods: We applied the light curve convex inversion method employing optical light curves obtained by using ground-based telescopes in three apparitions during 2006, 2016, and 2017, along with infrared light curves obtained by the Wide-field Infrared Survey Explorer satellite in 2010.
Results: Asteroid (5247) Krylov is spinning in a short axis mode characterized by rotation and precession periods of 368.7 and 67.27 h, respectively. The angular momentum vector orientation of Krylov is found to be λL = 298° and βL = -58°. The ratio of the rotational kinetic energy to the basic spin-state energy E/E0 ≃ 1.02 shows that the (5247) Krylov is about 2% excited state compared to the principal axis rotation state. The shape of (5247) Krylov can be approximated by an elongated prolate ellipsoid with a ratio of moments of inertia of Ia : Ib : Ic = 0.36 : 0.96 : 1. This is the first physical model of an NPA rotator among MBAs. The physical processes that led to the current NPA rotation cannot be unambiguously reconstructed.