Showing papers on "Yarkovsky effect published in 2020"
TL;DR: Greenberg et al. as mentioned in this paper analyzed both optical and radar astrometry for 600 near-Earth asteroids (NEAs) for the purpose of detecting and quantifying the Yarkovsky effect.
Abstract: Author(s): Greenberg, AH; Margot, J-L; Verma, AK; Taylor, PA; Hodge, SE | Abstract: The Yarkovsky effect is a thermal process acting upon the orbits of small celestial bodies, which can cause these orbits to slowly expand or contract with time. The effect is subtle (da/dt ~ 10^-4 au/My for a 1 km diameter object) and is thus generally difficult to measure. We analyzed both optical and radar astrometry for 600 near-Earth asteroids (NEAs) for the purpose of detecting and quantifying the Yarkovsky effect. We present 247 NEAs with measured drift rates, which is the largest published set of Yarkovsky detections. This large sample size provides an opportunity to examine the Yarkovsky effect in a statistical manner. In particular, we describe two independent population-based tests that verify the measurement of Yarkovsky orbital drift. First, we provide observational confirmation for the Yarkovsky effect's theoretical size dependence of 1/D, where D is diameter. Second, we find that the observed ratio of negative to positive drift rates in our sample is 2.34, which, accounting for bias and sampling uncertainty, implies an actual ratio of $2.7^{+0.3}_{-0.7}$. This ratio has a vanishingly small probability of occurring due to chance or statistical noise. The observed ratio of retrograde to prograde rotators is two times lower than the ratio expected from numerical predictions from NEA population studies and traditional assumptions about the sense of rotation of NEAs originating from various main belt escape routes. We also examine the efficiency with which solar energy is converted into orbital energy and find a median efficiency in our sample of 12%. We interpret this efficiency in terms of NEA spin and thermal properties.
31 citations
TL;DR: Based on a linearized model of the Yarkovsky effect, the dependence of the semimajor axis drift of a celestial body on its size, spinning obliquity, initial orbit and thermal parameters on its surface was investigated in this paper.
Abstract: Based on a linearized model of the Yarkovsky effect, we investigate in this paper the dependence of the semimajor axis drift $\Delta a$ of a celestial body on its size, spinning obliquity, initial orbit and thermal parameters on its surface. With appropriate simplification and approximation, we obtain the analytical solutions to the perturbation equations for the motion of asteroids influenced by the Yarkovsky effect, and they are then verified by numerical simulations of the full equations of motion. These solutions present explicitly the dependencies of $\Delta a$ on the thermal and dynamical parameters of the asteroid. With these analytical formulae for $\Delta a$, we investigate the combined seasonal and diurnal Yarkovsky effects. The critical points where the migration direction reverses are calculated and the consequent selective effects according to the size and rotation state of asteroids are discussed. %Solely the Yarkovsky effect is found to be able to produce some ring structure in the aged circumstellar debris disk. Finally, we apply the analytical formulae to calculate the migration of Eos family members. The space distribution of asteroids is well reproduced. Our calculations suggest that statistically the orientations of spin axes of family members satisfy a random-obliquity distribution, and the rotation rate $\omega_{\rm rot}$ of asteroid depends on its size $R$ by $\omega_{\rm rot}\propto R^{-1}$.
10 citations
TL;DR: In this article, lower limits on the time-scales for these objects to reach the planet's orbit, and 3 m as the approximate limiting radius above which a boulder drifts too slowly to avoid colliding with the planet, were established.
Abstract: An ice giant planet was recently reported orbiting white dwarf WD J0914+1914 at an approximate distance of 0.07 au. The striking non-detection of rocky pollutants in this white dwarf’s photosphere contrasts with the observations of nearly every other known white dwarf planetary system. Here, I analyse the prospects for exterior extant rocky asteroids, boulders, cobbles, and pebbles to radiatively drift inward past the planet due to the relatively high luminosity (0.1L⊙) of this particularly young (13 Myr) white dwarf. Pebbles and cobbles drift too slowly from Poynting–Robertson drag to bypass the planet, but boulders and asteroids are subject to the much stronger Yarkovsky effect. In this paper, I (i) place lower limits on the time-scales for these objects to reach the planet’s orbit, (ii) establish 3 m as the approximate limiting radius above which a boulder drifts too slowly to avoid colliding with the planet, and (iii) compute bounds on the fraction of boulders that succeed in traversing mean motion resonances and the planet’s Hill sphere to eventually pollute the star. Overall, I find that the planet acts as a barrier against rather than a facilitator for radiatively driven rocky pollution, suggesting that future rocky pollutants would most likely originate from distant scattering events.
9 citations
TL;DR: It is found that dynamically evolved Themis family objects on JFC-like orbits have semimajor axes between 3.15 au and 3.40 au for the vast majority of their time on such orbits, consistent with the strong role that the 2:1 mean-motion resonance with Jupiter likely plays in their dynamical evolution.
Abstract: Recent dynamical analyses suggest that some Jupiter family comets (JFCs) may originate in the main asteroid belt instead of the outer solar system. This possibility is particularly interesting given evidence that icy main-belt objects are known to be present in the Themis asteroid family. We report results from dynamical analyses specifically investigating the possibility that icy Themis family members could contribute to the observed population of JFCs. Numerical integrations show that such dynamical evolution is indeed possible via a combination of eccentricity excitation apparently driven by the nearby 2:1 mean-motion resonance with Jupiter, gravitational interactions with planets other than Jupiter, and the Yarkovsky effect. We estimate that, at any given time, there may be tens of objects from the Themis family on JFC-like orbits with the potential to mimic active JFCs from the outer solar system, although not all, or even any, may necessarily be observably active. We find that dynamically evolved Themis family objects on JFC-like orbits have semimajor axes between 3.15 au and 3.40 au for the vast majority of their time on such orbits, consistent with the strong role that the 2:1 mean-motion resonance with Jupiter likely plays in their dynamical evolution. We conclude that a contribution from the Themis family to the active JFC population is plausible, although further work is needed to better characterize this contribution.
8 citations
TL;DR: In this article, the authors explore the hypothesis that the population of Martian Trojans is the result of a balance between the production of new asteroids through the YORP effect and their eventual escape from the Trojan clouds through Yarkovsky-driven orbital evolution.
8 citations
TL;DR: In this article, a statistical code was developed to model the time evolution of the semi-major axis of an asteroid under YORP-Yarkovsky coupling, including the contributions of collisions.
Abstract: Any population of asteroids, like asteroid families, will disperse in semi-major axis due to the Yarkovsky effect. The amount of drift is modulated by the asteroid spin state evolution which determines the balance between the diurnal and seasonal Yarkovsky force. The asteroid's spin state is, in turn, controlled in part by the YORP effect. The otherwise smooth evolution of an asteroid can be abruptly altered by collisions, which can cause impulsive changes in the spin state and can move the asteroid onto a different YORP track. In addition, collisions may also alter the YORP parameters by changing the superficial features and overall shape of the asteroid. Thus, the coupling between YORP and Yarkovsky is also strongly affected by the impact history of each body. To investigate this coupling we developed a statistical code modeling the time evolution of semi--major axis under YORP-Yarkovsky coupling. It includes the contributions of NYORP (normal YORP), TYORP (tangential YORP) and collisions whose effects are deterministically calculated and not added in a statistical way. We find that both collisions and TYORP increase the dispersion of a family in semi-major axis by making the spin axis evolution less smooth and regular. We show that the evolution of a family's structure with time is complex and collisions randomize the YORP evolution. In our test families we do not observe the formation of a 'YORP-eye' in the semi-major axis vs. diameter distribution, even after a long period of time. If present, the 'YORP-eye' might be a relic of an initial ejection velocity pattern of the collisional fragments.
8 citations
TL;DR: In this article, the Yarkovsky effect has been used to estimate that there may be tens of objects from Themis family on JFC-like orbits with the potential to mimic active JFCs from the outer solar system, although not all, or even any, may necessarily be observably active.
Abstract: Recent dynamical analyses suggest that some Jupiter family comets (JFCs) may originate in the main asteroid belt instead of the outer solar system. This possibility is particularly interesting given evidence that icy main-belt objects are known to be present in the Themis asteroid family. We report results from dynamical analyses specifically investigating the possibility that icy Themis family members could contribute to the observed population of JFCs. Numerical integrations show that such dynamical evolution is indeed possible via a combination of eccentricity excitation apparently driven by the nearby 2:1 mean-motion resonance with Jupiter, gravitational interactions with planets other than Jupiter, and the Yarkovsky effect. We estimate that, at any given time, there may be tens of objects from the Themis family on JFC-like orbits with the potential to mimic active JFCs from the outer solar system, although not all, or even any, may necessarily be observably active. We find that dynamically evolved Themis family objects on JFC-like orbits have semimajor axes between 3.15 au and 3.40 au for the vast majority of their time on such orbits, consistent with the strong role that the 2:1 mean-motion resonance with Jupiter likely plays in their dynamical evolution. We conclude that a contribution from the Themis family to the active JFC population is plausible, although further work is needed to better characterize this contribution.
6 citations
TL;DR: In this article, the Yarkovsky effect was determined by fitting orbits of some asteroids with small perihelion distances using two methods based on minimization of the least square errors.
Abstract: The paper presents the Yarkovsky effect parameter determined by fitting orbits of some asteroids with small perihelion distances using two methods based on minimization of the least square errors. A comparative analysis of the obtained values showed good agreement between the results of these methods.
6 citations
TL;DR: In this article, the authors determined the formation age of the Clarissa family by modeling planetary perturbations as well as thermal drift of family members due to the Yarkovsky effect.
Abstract: The Clarissa family is a small collisional family composed of primitive C-type asteroids. It is located in a dynamically stable zone of the inner asteroid belt. In this work we determine the formation age of the Clarissa family by modeling planetary perturbations as well as thermal drift of family members due to the Yarkovsky effect. Simulations were carried out using the Swift-rmvs4 integrator modified to account for the Yarkovsky and Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effects. We ran multiple simulations starting with different ejection velocity fields of fragments, varying proportion of initially retrograde spins, and also tested different Yarkovsky/YORP models. Our goal was to match the observed orbital structure of the Clarissa family which is notably asymmetrical in the proper semimajor axis. The best fits were obtained with the initial ejection velocities < ~20 m/s of diameter D=2 km fragments, 4:1 preference for spin-up by YORP, and assuming that 80% of small family members initially had retrograde rotation. The age of the Clarissa family was found to be 56+/-6 Myr for the assumed asteroid density 1.5 g/cm3. Small variation of density to smaller or larger value would lead to slightly younger or older age estimates. This is the first case where the Yarkovsky effect chronology has been successfully applied to an asteroid family younger than 100 Myr.
5 citations
TL;DR: In this paper, a statistical code was developed to model the time evolution of the semi-major axis of an asteroid under YORP-Yarkovsky coupling, including the contributions of collisions.
Abstract: Any population of asteroids, like asteroid families, will disperse in semi-major axis due to the Yarkovsky effect. The amount of drift is modulated by the asteroid spin state evolution which determines the balance between the diurnal and seasonal Yarkovsky force. The asteroid's spin state is, in turn, controlled in part by the YORP effect. The otherwise smooth evolution of an asteroid can be abruptly altered by collisions, which can cause impulsive changes in the spin state and can move the asteroid onto a different YORP track. In addition, collisions may also alter the YORP parameters by changing the superficial features and overall shape of the asteroid. Thus, the coupling between YORP and Yarkovsky is also strongly affected by the impact history of each body. To investigate this coupling we developed a statistical code modeling the time evolution of semi--major axis under YORP-Yarkovsky coupling. It includes the contributions of NYORP (normal YORP), TYORP (tangential YORP) and collisions whose effects are deterministically calculated and not added in a statistical way. We find that both collisions and TYORP increase the dispersion of a family in semi-major axis by making the spin axis evolution less smooth and regular. We show that the evolution of a family's structure with time is complex and collisions randomize the YORP evolution. In our test families we do not observe the formation of a 'YORP-eye' in the semi-major axis vs. diameter distribution, even after a long period of time. If present, the 'YORP-eye' might be a relic of an initial ejection velocity pattern of the collisional fragments.
4 citations
TL;DR: In this article, the authors developed a six-part collisional evolution model of the main asteroid belt (MB) and used it to study the contribution of different regions of the MB to the near-earth asteroids (NEAs).
Abstract: Aims. We developed a six-part collisional evolution model of the main asteroid belt (MB) and used it to study the contribution of the different regions of the MB to the near-earth asteroids (NEAs). Methods. We built a statistical code called ACDC that simulates the collisional evolution of the MB split into six regions (namely Inner, Middle, Pristine, Outer, Cybele and High-Inclination belts) according to the positions of the major resonances present there ($
u_{6}$, 3:1J, 5:2J, 7:3J and 2:1J). We consider the Yarkovsky effect and the mentioned resonances as the main mechanism that removes asteroids from the different regions of the MB and delivers them to the NEA region. We calculated the evolution of the NEAs coming from the different source regions by considering the bodies delivered by the resonances and mean dynamical timescales in the NEA population. Results. Our model is in agreement with the major observational constraints associated with the MB, such as the size distributions of the different regions of the MB and the number of large asteroid families. It is also able to reproduce the observed NEAs with H < 16 and agrees with recent estimations for H < 20, but deviates for smaller sizes. We find that most sources make a significant contribution to the NEAs; however the Inner and Middle belts stand out as the most important source of NEAs followed by the Outer belt. The contributions of the Pristine and Cybele regions are minor. The High-Inclination belt is the source of only a fraction of the actual observed NEAs with high inclination, as there are dynamical processes in that region that enable asteroids to increase and decrease their inclinations.
TL;DR: In this article, the Yarkovsky effect was studied for a set of asteroids with small perihelion distance and it was shown that in most cases, this effect leads to a decrease in the confidence region.
Abstract: We present estimates of the transversal acceleration associated with the Yarkovsky effect for a set of asteroids with small perihelion distance. It is shown that in most cases, this effect leads to a decrease in the confidence region. The motion of asteroid 504181 2006 TC that according to our estimates is most strongly influenced by this effect is studied in detail. Close approaches and apsidal-nodal resonances with planets are identified and motion predictability intervals are evaluated using the OMEGNO parameter.
TL;DR: In this paper, the authors investigated the effects of the 7/3 MMR with Jupiter (J7/3MM) on the transportation of asteroids from the Koronis family and the Eos family that reside, respectively, on the inner and outer sides of the resonance using numerical simulations.
Abstract: The Yarkovsky effect plays an important role in asteroids drifting in the inner Solar System. In the main belt, many asteroids are continuously pushed by the Yarkovsky effect into regions of different mean motion resonances (MMRs) and then ejected after a period of time, due to the instability of MMRs. They are considered as the principal source of near-Earth objects. In this paper, we investigate the effects of the 7/3 MMR with Jupiter (J7/3 MMR) on the transportation of asteroids from the Koronis family and the Eos family that reside, respectively, on the inner and outer sides of the resonance using numerical simulations. The J7/3 MMR acts like a selective barrier to migrating asteroids. The fraction of asteroids that successfully cross through the resonance and the escape rate from the resonance are found to depend on the Yarkovsky drifting rate, the initial inclination and the migrating direction. The excitation of eccentricity and inclination due to the combined influence from both the resonance and the Yarkovsky effect are discussed. Only the eccentricity can be pumped up considerably, and it is attributed mainly to the resonance. In the observational data, family members are also found in the resonance and on the opposite side of the resonance with respect to the corresponding family centre. The existence of these family members is explained using our results of numerical simulations. Finally, the replenishment of asteroids in the J7/3 MMR and its transportation of asteroids are discussed.
TL;DR: In this paper, the authors analyzed the dynamic evolution of a number of young asteroid pairs in close orbits in order to constrain their ages, and used several methods of pair selection and estimation of their age.
Abstract: We analyzed the dynamic evolution of a number of young asteroid pairs in close orbits in order to constrain their ages. Several methods of pair selection and estimation of their age are used: analysis of convergence of orbital elements; estimation of the Kholshevnikov metrics in the space of Keplerian orbital elements; estimation of relative distances and velocities at the moments of asteroid close approaches. Estimates of the age of asteroid pairs are obtained depending on the drift velocities of the semimajor axes of the orbits, due to the Yarkovsky effect.
TL;DR: In this paper, the results of orbital evolution construction for Near Earth asteroid (NEA) 137924 2000 BD19 with a small perihelion distance on the interval (−7500, 5000) years were revealed.
TL;DR: In this paper, the authors investigated the effects of the 7/3 MMR with Jupiter (J7/3MM) on the transportation of asteroids from Koronis and Eos families that reside respectively on the inner and outer side of the resonance.
Abstract: Many asteroids in the main belt are continuously pushed by Yarkovsky effect into regions of different mean motion resonances (MMRs) and then ejected out. They are considered as the principal source of near-Earth objects. We investigate in this paper the effects of the 7/3 MMR with Jupiter (J7/3 MMR) on the transportation of asteroids from Koronis and Eos families that reside respectively on the inner and outer side of the resonance. The fraction of asteroids that make successful crossing through the resonance and the escaping rate from the resonance are found to depend on the Yarkovsky drifting rate, the initial inclination and the migrating direction. The excitation of eccentricity and inclination due to the combined influence from both the resonance and Yarkovsky effect is discussed. Only the eccentricity can be pumped up considerably, and it is attributed mainly to the resonance. In the observational data, family members are also found in the resonance and on the opposite side of the resonance with respect to the corresponding family centre. The existence of these family members is explained using our results of numerical simulations. Finally, the replenishment of asteroids in the J7/3 MMR and the transportation of asteroids by it are discussed.
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TL;DR: In this article, the authors determined the formation age of the Clarissa family by modeling planetary perturbations as well as thermal drift of family members due to the Yarkovsky effect.
Abstract: The Clarissa family is a small collisional family composed of primitive C-type asteroids. It is located in a dynamically stable zone of the inner asteroid belt. In this work we determine the formation age of the Clarissa family by modeling planetary perturbations as well as thermal drift of family members due to the Yarkovsky effect. Simulations were carried out using the Swift-rmvs4 integrator modified to account for the Yarkovsky and Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effects. We ran multiple simulations starting with different ejection velocity fields of fragments, varying proportion of initially retrograde spins, and also tested different Yarkovsky/YORP models. Our goal was to match the observed orbital structure of the Clarissa family which is notably asymmetrical in the proper semimajor axis. The best fits were obtained with the initial ejection velocities < ~20 m/s of diameter D=2 km fragments, 4:1 preference for spin-up by YORP, and assuming that 80% of small family members initially had retrograde rotation. The age of the Clarissa family was found to be 56+/-6 Myr for the assumed asteroid density 1.5 g/cm3. Small variation of density to smaller or larger value would lead to slightly younger or older age estimates. This is the first case where the Yarkovsky effect chronology has been successfully applied to an asteroid family younger than 100 Myr.
TL;DR: The multicolor photometric method at the Robophot telescope as mentioned in this paper was used to investigate asteroids with the multi-colors photometric methods at the Dall-Kirkham system.
Abstract: We consider prospects for investigating asteroids with the multicolor photometric method at the Robophot telescope—a robotic telescope of the Dall–Kirkham system with a 0.6-m primary mirror and a focal length of 4.2 m. It is equipped with a three-channel photometer with the g', r', and i' filters of the SDSS photometric system, and the field of view is 20′. The use of a three-channel photometer in observations of small bodies will make it possible to construct multicolor light curves without phase delays. Diagrams of the r' – i' and g' – r' color indices will provide the means of classifying the C- and S-type asteroids. From the high-accuracy light curves, the rotation parameters of asteroids can be determined, for which it is necessary to take the Yarkovsky effect into account correctly. The results of multicolor photometric observations at the Robophot telescope will allow for solving complex scientific problems related to the studies of the physical and dynamic evolution of small bodies in the Solar System.
01 Nov 2020
01 Jan 2020
TL;DR: In this paper, the authors investigated the relation between the asteroid family Yarkovsky V-shape and the limiting speed of an asteroid's semi-major axes and found that the breakpoints of the very old asteroid families, crossed by relatively strong and/or weak mean motion resonances on both sides very close to the parent body, are exactly the inverse of the diameters in the a versus 1=D plane.
Abstract: The Yarkovsky effect is an important force to consider in order to understand
the long-term dynamics of asteroids. This non-gravitational force affects the
orbital elements of objects revolving around a source of heat, especially
their semi-major axes. Following the recently defined `limiting' value of the
Yarkovsky drift speed at 7x10-5 au/Myr in Milic Žitnik (2019) (below this
value of speed asteroids typically jump quickly across the mean motion
resonances), we decided to investigate the relation between the asteroid
family Yarkovsky V-shape and the `limiting' Yarkovsky drift speed of
asteroid's semi-major axes. We have used the known scaling formula to
calculate the Yarkovsky drift speed (Spoto et al. 2015) in order to
determine the inner and outer `limiting' diameters (for the inner and outer
V-shape borders) from the `limiting' Yarkovsky drift speed. The method was
applied to 11 asteroid families of different taxonomic classes, origin type
and age, located throughout the Main Belt. Here, we present the results of
our calculation on relationship between asteroid families' V-shapes (crossed
by strong and/or weak mean motion resonances) and the `limiting' diameters
in the (a, 1=D) plane. Our main conclusion is that the `breakpoints' in
changing V-shape of the very old asteroid families, crossed by relatively
strong mean motion resonances on both sides very close to the parent body,
are exactly the inverse of `limiting' diameters in the a versus 1=D plane.
This result uncovers a novel interesting property of asteroid families'
Yarkovsky V-shapes.