The Yarkovsky effect for 99942 Apophis

Vokrouhlický, David; Farnocchia, Davide; Čapek, D.; Chesley, Steven R.; Pravec, Petr; Scheirich, P.; Müller, Thomas

doi:10.1016/j.icarus.2015.01.011

Cited by 45 publications

(29 citation statements)

References 36 publications

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“…As discussed by Vokrouhlický et al (2015b), for a tumbling asteroid the Yarkovsky effect essentially depends on the rotational angular momentum rather than the spin axis. Therefore, if the fraction of non-principalaxis rotators were significant, our obliquity distribution would be more reflective of the orientation of the angular momentum vector than that of the spin axis.…”

Section: Discussionmentioning

confidence: 99%

“…This perturbation is important to understand the long-term dynamics of the asteroid population since it is a driving factor for feeding resonances in the main belt and transporting asteroids to the inner Solar System (Farinella et al 1998;Morbidelli & Vokrouhlickỳ 2003;. The Yarkovsky effect is also relevant for impact hazard predictions where highprecision ephemeris predictions are required (Giorgini et al 2002;Chesley 2006;Giorgini et al 2008;Chesley et al 2014;Spoto et al 2014;Vokrouhlický et al 2015b). …”

Section: Introductionmentioning

confidence: 99%

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Constraints on the near-Earth asteroid obliquity distribution from the Yarkovsky effect

Tardioli

Farnocchia

Rozitis

et al. 2017

A&A

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Aims. From lightcurve and radar data we know the spin axis of only 43 near-Earth asteroids. In this paper we attempt to constrain the spin axis obliquity distribution of near-Earth asteroids by leveraging the Yarkovsky effect and its dependence on an asteroid's obliquity.Methods. By modeling the physical parameters driving the Yarkovsky effect, we solve an inverse problem where we test different simple parametric obliquity distributions. Each distribution results in a predicted Yarkovsky effect distribution that we compare with a χ 2 test to a dataset of 125 Yarkovsky estimates.Results. We find different obliquity distributions that are statistically satisfactory. In particular, among the considered models, the best-fit solution is a quadratic function, which only depends on two parameters, favors extreme obliquities, consistent with the expected outcomes from the YORP effect, has a 2:1 ratio between retrograde and direct rotators, which is in agreement with theoretical predictions, and is statistically consistent with the distribution of known spin axes of near-Earth asteroids.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Constraints on the near-Earth asteroid obliquity distribution from the Yarkovsky effect

Tardioli

Farnocchia

Rozitis

et al. 2017

A&A

View full text Add to dashboard Cite

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“…Images of Apophis were obtained using three different Finally, the presented improvement in the determination of the thermal inertia is very important in order to evaluate the Yarkovsky effect on the orbital evolution of Apophis (Vokrouhlický et al 2015). Using the Müller et al (2014) range of possible Γ-values, they estimate the drift of the Apophis orbital semimajor axis da/dt to be in a range between −11 × 10 −4…”

Section: Discussionmentioning

confidence: 99%

“…The Yarkovsky effect depends upon several poorly known parameters, such as the albedo, size, thermal inertia, and pole orientation of the object. Recently Vokrouhlický et al (2015) evaluated the Yarkovsky effect on the orbital evolution of Apophis.…”

Section: Introductionmentioning

confidence: 99%

“…They used the spin and shape model and absolute magnitude H = 19.09 ± 0.19 by Pravec et al (2014) Delbo et al (2007) from their p V determination is the result of a different value of H (H = 19.09 and H = 19.7, respectively). The Vokrouhlický et al (2015) results use the Pravec et al (2014) and Müller et al (2014) results to evaluate the Yarkovsky effect on the orbital evolution of Apophis; in particular, they use the range of Γ values provided by Müller et al (2014).…”

Section: Introductionmentioning

confidence: 99%

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GTC/CanariCam observations of (99942) Apophis

Licandro

Müller

Álvarez

et al. 2015

A&A

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Context. The potentially hazardous asteroid (PHA) (99942) Apophis is one of the most remarkable near-Earth asteroids (NEA) in terms of impact hazard. A good determination of its surface thermal inertia is very important in order to evaluate the Yarkovsky effect on its orbital evolution. Aims. We present thermal infrared observations obtained on January 29, 2013, with CanariCam mid-infrared camera/spectrograph attached to the Gran Telescopio CANARIAS (GTC, Roque de los Muchachos Observatory, La Palma, Spain) using the Si2-8.7, Si6-12.5, and Q1-17.65 filters with the aim of deriving Apophis' diameter (D), geometric albedo (p V ), and thermal inertia (Γ). Methods. We performed a detailed thermophysical model analysis of the GTC data combined with previously published thermal data obtained using Herschel Space Observatory PACS instrument at 70, 100, and 160 μm.Results. The thermophysical model fit of the data favors low surface roughness solutions (within a range of roughness slope angles rms between 0.1 and 0.5), and constrains the effective diameter, visible geometric albedo, and thermal inertia of Apophis to be D eff = 380-393 m, p V = 0.24-0.33 (assuming absolute magnitude H = 19.09 ± 0.19) and Γ = 50-500 Jm −2 −0.5 K −1 , respectively.

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