Evolution of the obliquities for ten asteroids

Skoglöv, Erik; Magnusson, P.; Dahlgren, M.

doi:10.1016/s0032-0633(96)00039-6

Cited by 28 publications

(29 citation statements)

References 6 publications

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“…The obliquity variations are larger when the orbital inclination is higher (Fig. 1), something that also was noted by Skoglöv & Erikson (2002).…”

Section: Spin Vector Integration Excluding the Yarkovsky Forcesupporting

confidence: 73%

“…(39) and (40), γ = α = 0 and the direct influences on the spin vector evolution from variations in a and e disappear. As can be seen in Skoglöv & Erikson (2002), the variations and size of the orbital inclination, I, are the most important causes for the size of the regular obliquity changes of main belt objects (see also Fig. 1).…”

Section: Spin Vector Integration Excluding the Yarkovsky Forcementioning

confidence: 94%

“…these studies and the references given there. In Skoglöv et al (1996) and in Skoglöv (1997), the equations for the spin vector evolution were adapted for the asteroids. The orbital and spin elements of the asteroids are affected by gravitational as well as thermal forces.…”

Section: The Connection Between the Orbital And Spin Vector Evolutionsmentioning

confidence: 99%

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The influence on the spin vectors of asteroids from the Yarkovsky effect

Skoglöv

2002

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Abstract. The spin vector evolution of a solar system object is connected to the orbital evolution of the body. The orbital and spin elements of the asteroids are affected by gravitational as well as thermal forces. When the spin rate, shape and orbital evolution of an object are known, the secular spin vector evolution may be determined. In this study, the orbital and spin vector evolutions of a number of artificial objects are numerically integrated, with special consideration taken to the seasonal and diurnal variants of the Yarkovsky force. The thermal force known as the Yarkovsky effect may perturb the orbital elements of an asteroid and thereby also affect the direction of the spin vector. Concentrating on spherical bodies, the spin axis evolution of bare and regolith covered main belt objects with radii larger than 50 m is examined, especially considering the seasonal and diurnal Yarkovsky forces. The combined effects on the spin vector evolution from these forces and induced periodical perturbations on the orbital elements are also studied. It is found that the effects on the spin vector evolution from the Yarkovsky force always are small or negligible for kilometer sized objects over time periods of ∼100 Myr or more. The effects are doubled when the object radius is halved. During a given time period, the influences from the seasonal Yarkovsky force on the spin vector evolution of bare basaltic bodies are about 2-3 times as large as those on iron-rich ones. However, since the expected time, t rot , before the spin axis direction is changed by a collisional event is about half as long for a bare basaltic object as for an equal sized iron-rich one, the seasonal Yarkovsky force may be of approximately the same importance for both classes of objects. The effects on regolith covered objects from this force are considerably smaller. On the other hand, the influences from the diurnal Yarkovsky effect are much stronger on regolith covered objects than on bare ones. The effect on the spin vector evolution from both variants of the Yarkovsky force seems to be small for all the objects studied unless very long time periods are considered. The size of t rot is dependent on several factors, but the influences from the Yarkovsky force on the spin axis evolution over the present age of the solar system are always negligible when the object radius is larger than ∼10 km. Note that the effects studied in this paper should not be confused with the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect.

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“…The obliquity variations are larger when the orbital inclination is higher (Fig. 1), something that also was noted by Skoglöv & Erikson (2002).…”

Section: Spin Vector Integration Excluding the Yarkovsky Forcesupporting

confidence: 73%

Section: Spin Vector Integration Excluding the Yarkovsky Forcementioning

confidence: 94%

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The influence on the spin vectors of asteroids from the Yarkovsky effect

Skoglöv

2002

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“…One branch of these studies originated from the works of Skoglöv and his collaborators about two decades ago (e.g., Skoglöv et al 1996;Skoglöv 1997Skoglöv , 1998. While planting a seed of interest, these works were mainly of a theoretical nature without immediate applications in mind.…”

Section: Introductionmentioning

confidence: 99%

Low-frequency Slivan states in the outer main belt?

Vraštil

Vokrouhlický

2016

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Context. Spin states of several main belt asteroids have been recently found to reside in what is called the Slivan state, namely a secular spin-orbit resonance with the s 6 mode of their orbital precession in space. Aims. We examine a possibility of the Slivan states of asteroids with other than orbital s 6 precession frequency. Methods. The asteroids' orbital and spin states are numerically propagated using well-tested computer codes. We select parameter space favorable for the Slivan-state capture with the s 7 frequency mode of the orbital precession. The stability of these states is numerically verified. Results. We find that asteroid (184) Dejopeja has a spin state captured in (or very nearly) the Slivan state with the s 7 orbital frequency. In general, such a situation may favorably occur for low-inclination orbits in the outermost part of the main asteroid belt. We expect these states to be common among the Themis family members.

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“…Gladman et al 1996;Peale 1999), and even planets (e.g., Colombo 1966;Ward 1975;Peale 2006), and they are thus significant for understanding the longterm spin evolution of bodies in planetary systems. Nevertheless, applications to asteroid spin states were limited so far (e.g., Skoglöv et al 1996;Skoglöv 1997Skoglöv , 1998Vokrouhlický et al 2005). 2 An exact identification of the Flora family membership is complicated by the significant dynamical chaoticity and high density of asteroids in the inner main-belt.…”

Section: Introductionmentioning

confidence: 99%

Inner main belt asteroids in Slivan states?

Vraštil

Vokrouhlický

2015

A&A

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Context. The spin state of ten asteroids in the Koronis family has previously been determined. Surprisingly, all four asteroids with prograde rotation were shown to have spin axes nearly parallel in the inertial space. All asteroids with retrograde rotation had large obliquities and rotation periods that were either short or long. The Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect has been demonstrated to be able to explain all these peculiar facts. In particular, the effect causes the spin axes of the prograde rotators to be captured in a secular spin-orbit resonance known as Cassini state 2, a configuration dubbed "Slivan state". Aims. It has been proposed based on an analysis of a sample of asteroids in the Flora family that Slivan states might also exist in this region of the main belt. This is surprising because convergence of the proper frequency s and the planetary frequency s 6 was assumed to prevent Slivan states in this zone. We therefore investigated the possibility of a long-term stable capture in the Slivan state in the inner part of the main belt and among the asteroids previously observed. Methods. We used the swift integrator to determine the orbital evolution of selected asteroids in the inner part of the main belt. We also implemented our own secular spin propagator into the swift code to efficiently analyze their spin evolution. Results. Our experiments show that the previously suggested Slivan states of the Flora-region asteroids are marginally stable for only a small range of the flattening parameter ∆. Either the observed spins are close to the Slivan state by chance, or additional dynamical effects that were so far not taken into account change their evolution. We find that only the asteroids with very low-inclination orbits (lower than 4• , for instance) could follow a similar evolution path as the Koronis members and be captured in their spin state into the Slivan state. A greater number of asteroids in the inner main-belt Massalia family, which are at a slightly larger heliocentric distance and at lower inclination orbits than in the Flora region, may have their spin in the Slivan state.

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Evolution of the obliquities for ten asteroids

Cited by 28 publications

References 6 publications

The influence on the spin vectors of asteroids from the Yarkovsky effect

The influence on the spin vectors of asteroids from the Yarkovsky effect

Low-frequency Slivan states in the outer main belt?

Inner main belt asteroids in Slivan states?

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