1
|
Abstract
Asteroids are primitive Solar System bodies that evolve both collisionally and through disruptions arising from rapid rotation. These processes can lead to the formation of binary asteroids and to the release of dust, both directly and, in some cases, through uncovering frozen volatiles. In a subset of the asteroids called main-belt comets, the sublimation of excavated volatiles causes transient comet-like activity. Torques exerted by sublimation measurably influence the spin rates of active comets and might lead to the splitting of bilobate comet nuclei. The kilometre-sized main-belt asteroid 288P (300163) showed activity for several months around its perihelion 2011 (ref. 11), suspected to be sustained by the sublimation of water ice and supported by rapid rotation, while at least one component rotates slowly with a period of 16 hours (ref. 14). The object 288P is part of a young family of at least 11 asteroids that formed from a precursor about 10 kilometres in diameter during a shattering collision 7.5 million years ago. Here we report that 288P is a binary main-belt comet. It is different from the known asteroid binaries in its combination of wide separation, near-equal component size, high eccentricity and comet-like activity. The observations also provide strong support for sublimation as the driver of activity in 288P and show that sublimation torques may play an important part in binary orbit evolution.
Collapse
|
2
|
Keller HU, Barbieri C, Koschny D, Lamy P, Rickman H, Rodrigo R, Sierks H, A’Hearn MF, Angrilli F, Barucci MA, Bertaux JL, Cremonese G, Da Deppo V, Davidsson B, De Cecco M, Debei S, Fornasier S, Fulle M, Groussin O, Gutierrez PJ, Hviid SF, Ip WH, Jorda L, Knollenberg J, Kramm JR, Kührt E, Küppers M, Lara LM, Lazzarin M, Moreno JL, Marzari F, Michalik H, Naletto G, Sabau L, Thomas N, Wenzel KP, Bertini I, Besse S, Ferri F, Kaasalainen M, Lowry S, Marchi S, Mottola S, Sabolo W, Schröder SE, Spjuth S, Vernazza P. E-Type Asteroid (2867) Steins as Imaged by OSIRIS on Board Rosetta. Science 2010; 327:190-3. [DOI: 10.1126/science.1179559] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- H. U. Keller
- Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany
| | | | - D. Koschny
- European Space and Technology Centre, Noordwijk, Netherlands
| | - P. Lamy
- Laboratoire d'Astrophysique de Marseille, Université de Provence, Marseille, France
| | - H. Rickman
- Institute för Astronomi och Rymdfysik, Uppsala, Sweden
- Polish Academy of Sciences Space Research Center, Warsaw, Poland
| | - R. Rodrigo
- Instituto de Astrofísica de Andalucía–Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - H. Sierks
- Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany
| | | | | | | | - J.-L. Bertaux
- Services d’Aéronomie de CNRS, Verrières le Buisson, France
| | | | - V. Da Deppo
- Consiglio Nazionale delle Ricerche-Istituto Nazionale per la Fisica della Materia, Luxor, Padova, Italy
| | - B. Davidsson
- Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden
| | | | - S. Debei
- University of Padova, Padova, Italy
| | | | - M. Fulle
- International School for Advanced Studies, Trieste, Italy
| | - O. Groussin
- Laboratoire d'Astrophysique de Marseille, Université de Provence, Marseille, France
| | - P. J. Gutierrez
- Instituto de Astrofísica de Andalucía–Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - S. F. Hviid
- Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany
| | - W.-H. Ip
- National Central University, Jhongli City, Taiwan
| | - L. Jorda
- Laboratoire d'Astrophysique de Marseille, Université de Provence, Marseille, France
| | | | - J. R. Kramm
- Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany
| | - E. Kührt
- German Aerospace Center, Berlin, Germany
| | - M. Küppers
- European Space Astronomy Centre (ESAC), Madrid, Spain
| | - L.-M. Lara
- Instituto de Astrofísica de Andalucía–Consejo Superior de Investigaciones Científicas, Granada, Spain
| | | | - J. Lopez Moreno
- Instituto de Astrofísica de Andalucía–Consejo Superior de Investigaciones Científicas, Granada, Spain
| | | | - H. Michalik
- Institute of Computer and Network Engineering, Braunschweig, Germany
| | | | - L. Sabau
- Instituto Nacional de Técnica Aérospacial, Torrejon de Ardoz, Spain
| | - N. Thomas
- Physikalisches Institut der Universität Bern, Switzerland
| | - K.-P. Wenzel
- European Space and Technology Centre, Noordwijk, Netherlands
| | - I. Bertini
- Instituto de Astrofísica de Andalucía–Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - S. Besse
- Laboratoire d'Astrophysique de Marseille, Université de Provence, Marseille, France
| | - F. Ferri
- University of Padova, Padova, Italy
| | | | - S. Lowry
- University of Kent, Canterbury, UK
| | | | - S. Mottola
- German Aerospace Center, Berlin, Germany
| | - W. Sabolo
- Instituto de Astrofísica de Andalucía–Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - S. E. Schröder
- Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany
| | - S. Spjuth
- Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany
| | - P. Vernazza
- European Space and Technology Centre, Noordwijk, Netherlands
| |
Collapse
|
4
|
Kaasalainen M, Durech J, Warner BD, Krugly YN, Gaftonyuk NM. Acceleration of the rotation of asteroid 1862 Apollo by radiation torques. Nature 2007; 446:420-2. [PMID: 17344861 DOI: 10.1038/nature05614] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2006] [Accepted: 01/15/2007] [Indexed: 11/08/2022]
Abstract
The anisotropic reflection and thermal re-emission of sunlight from an asteroid's surface acts as a propulsion engine. The net propulsion force (Yarkovsky effect) changes the orbital dynamics of the body at a rate that depends on its physical properties; for irregularly shaped bodies, the propulsion causes a net torque (the Yarkovsky-O'Keefe-Radzievskii-Paddack or YORP effect) that can change the object's rotation period and the direction of its rotation axis. The Yarkovsky effect has been observed directly, and there is also indirect evidence of its role in the orbital evolution of asteroids over long time intervals. So far, however, only indirect evidence exists for the YORP effect through the clustering of the directions of rotation axes in asteroid families. Here we report a change in the rotation rate of the asteroid 1862 Apollo, which is best explained by the YORP mechanism. The change is fairly large and clearly visible in photometric lightcurves, amounting to one extra rotation cycle in just 40 years even though Apollo's size is well over one kilometre. This confirms the prediction that the YORP effect plays a significant part in the dynamical evolution of asteroids.
Collapse
Affiliation(s)
- Mikko Kaasalainen
- Department of Mathematics and Statistics, Rolf Nevanlinna Institute, PO Box 68, FI-00014 University of Helsinki, Finland.
| | | | | | | | | |
Collapse
|
5
|
Lowry SC, Fitzsimmons A, Pravec P, Vokrouhlicky D, Boehnhardt H, Taylor PA, Margot JL, Galád A, Irwin M, Irwin J, Kusnirák P. Direct detection of the asteroidal YORP effect. Science 2007; 316:272-4. [PMID: 17347414 DOI: 10.1126/science.1139040] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect is believed to alter the spin states of small bodies in the solar system. However, evidence for the effect has so far been indirect. We report precise optical photometric observations of a small near-Earth asteroid, (54509) 2000 PH5, acquired over 4 years. We found that the asteroid has been continuously increasing its rotation rate omega over this period by domega/dt = 2.0 (+/-0.2) x 10(-4) degrees per day squared. We simulated the asteroid's close Earth approaches from 2001 to 2005, showing that gravitational torques cannot explain the observed spin rate increase. Dynamical simulations suggest that 2000 PH5 may reach a rotation period of approximately 20 seconds toward the end of its expected lifetime.
Collapse
Affiliation(s)
- Stephen C Lowry
- School of Mathematics and Physics, Queen's University Belfast, Belfast BT7 1NN, UK.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|