Long-Term Evolution of Rotational States and Nongravitational Effects for Halley-like Cometary Nuclei

The excited spin state of Comet 2P/Encke

“…A clear detection of two independent frequencies would seem to guarantee easy identification of excited rotators. However, Samarasinha and Belton (1995) have found that in the evolution of excited spin states of elongated objects there is a tendency for them to spend much time in states where the two frequencies are roughly commensurate. 1P/Halley is apparently a case like this and, as we have seen in Table 3, it is not easy to distinguish between fully relaxed and excited rotation just on the basis of light curve periodicities alone.…”

Rotational excitation and damping as probes of interior structures of asteroids and comets

“…In addition, Gutierrez et al (2003) derives the necessary condition governing the ratio between the component torques and moments of inertia for rotational excitation. For further discussions on the process of rotational excitation and the excitation time scale, the reader is referred to Samarasinha and Belton (1995), Neishtadt et al (2002), and Gutierrez et al (2003).…”

“…As mentioned earlier, Euler's equations of motion allows one to monitor changes in the spin state (e.g., Wilhelm 1987;Peale and Lissauer 1989;Samarasinha and Belton 1995;Gutierrez et al 2005). Everything else being equal, for almost all conceivable processes of rotational excitation due to external torques (in contrast to rotational excitation caused primarily by moment of inertia altering events), the external torque can be expressed as being proportional to r n (where r is the effective radius of the object and the exponent n is typically greater than zero).…”

Evolution of Comet Nucleus Rotation

“…However, his model of reactive torque formation does not take into account more current results and ideas. Thus the averaged equations in Julian (1988) cannot be used to study the secular effects found in Peale and Lissauer (1989) and Samarasinha and Belton (1995), where sublimation processes are described more realistically. Additionally, in Julian (1988), only principal axis rotation states were considered, while in the current analysis we consider the space of all possible rotations.…”

“…In Wilhelm (1987), Peale and Lissauer (1989), Julian (1990), Samarasinha and Belton (1995), and Jorda and Licandro (in press), the spin evolution of comet nuclei was investigated by numerical integration of the equations of nucleus rotation. In the present paper, we seek to develop a more systematic approach to the problem by studying the rotational evolution of a cometary nucleus using the averaging method (Bogolyubov andMitropolsky 1961, Arnold 1978).…”