TY - JOUR
T1 - Orientation and rotational parameters of asteroid 4179 toutatis
T2 - New insights from chang'e-2's close flyby
AU - Zhao, Yuhui
AU - Ji, Jianghui
AU - Huang, Jiangchuan
AU - Hu, Shoucun
AU - Hou, Xiyun
AU - Li, Yuan
AU - Ip, Wing Huen
N1 - Publisher Copyright:
© 2015 The Authors.
PY - 2015/4/24
Y1 - 2015/4/24
N2 - In this paper, we investigate the rotational dynamics of the ginger-shaped near-Earth asteroid 4179 Toutatis, which was closely observed by Chang'e-2 at a distance of 770 ± 120 m from the asteroid's surface during the outbound flyby on 2012 December 13. A sequence of highresolution images was acquired during the flyby mission. In combination with ground-based radar observations collected over the last two decades, we analyse these flyby images and determine the orientation of the asteroid at the flyby epoch. The 3-1-3 Euler angles of the conversion matrix from the J2000 ecliptic coordinate system to the body-fixed frame are evaluated to be -20.°1 ± 1°, 27.°6 ± 1° and 42.°2 ± 1°, respectively. The least-squares method is utilized to determine the rotational parameters and spin state of Toutatis. The characteristics of the spin-state parameters and angular momentum variations are extensively studied using numerical simulations, which confirm those reported by Takahashi, Busch & Scheeres (2013, AJ, 146, 95). The large amplitude of the precession of Toutatis is assumed to be responsible for its tumbling attitude as observed from Earth. The angular momentum orientation of Toutatis is determined to be described by λH = 180.°2+0.°2 -0.°3 and βH = -54.°75+0.°15 -0.°10, implying that it has remained nearly unchanged for two decades. Furthermore, using Fourier analysis to explore the change in the orientation of the axes of Toutatis, we reveal that the two rotational periods are 5.38 and 7.40 d, respectively, consistent with the results of the earlier investigation. Hence, our investigation provides a clear understanding of the state of the rotational dynamics of Toutatis.
AB - In this paper, we investigate the rotational dynamics of the ginger-shaped near-Earth asteroid 4179 Toutatis, which was closely observed by Chang'e-2 at a distance of 770 ± 120 m from the asteroid's surface during the outbound flyby on 2012 December 13. A sequence of highresolution images was acquired during the flyby mission. In combination with ground-based radar observations collected over the last two decades, we analyse these flyby images and determine the orientation of the asteroid at the flyby epoch. The 3-1-3 Euler angles of the conversion matrix from the J2000 ecliptic coordinate system to the body-fixed frame are evaluated to be -20.°1 ± 1°, 27.°6 ± 1° and 42.°2 ± 1°, respectively. The least-squares method is utilized to determine the rotational parameters and spin state of Toutatis. The characteristics of the spin-state parameters and angular momentum variations are extensively studied using numerical simulations, which confirm those reported by Takahashi, Busch & Scheeres (2013, AJ, 146, 95). The large amplitude of the precession of Toutatis is assumed to be responsible for its tumbling attitude as observed from Earth. The angular momentum orientation of Toutatis is determined to be described by λH = 180.°2+0.°2 -0.°3 and βH = -54.°75+0.°15 -0.°10, implying that it has remained nearly unchanged for two decades. Furthermore, using Fourier analysis to explore the change in the orientation of the axes of Toutatis, we reveal that the two rotational periods are 5.38 and 7.40 d, respectively, consistent with the results of the earlier investigation. Hence, our investigation provides a clear understanding of the state of the rotational dynamics of Toutatis.
KW - Minor planets, asteroids: individual: toutatis
KW - Planets and satellites: dynamical evolution and stability
KW - Planets and satellites: interiors
UR - http://www.scopus.com/inward/record.url?scp=84938151879&partnerID=8YFLogxK
U2 - 10.1093/mnras/stv792
DO - 10.1093/mnras/stv792
M3 - 期刊論文
AN - SCOPUS:84938151879
SN - 0035-8711
VL - 450
SP - 3620
EP - 3632
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 4
ER -