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| Titel |
The P/2010 A2 asteroid collision confirmed by Rosetta/OSIRIS observation |
| VerfasserIn |
Cecilia Tubiana, Colin Snodgrass, Jean-Baptiste Vincent |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250047659
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| Zusammenfassung |
| The discovery of P/2010 A2 by the LINEAR survey in January 2010 [2] revealed an object
displaying a large trail of material similar in shape to a cometary tail although no central
condensation or coma could be detected. The appearance of this object in an asteroidal orbit
in the inner main belt attracted attention as a potential new member of the Main Belt Comets
class (MBCs) [4] but the discovery of a nucleus [6], with a diameter of 120 m [5], around
1500 km away from the trail implied that the extended object we were seeing could be the
debris trail from a recent collision rather than the tail of a comet. Due to the low
inclination of its orbit, it is difficult to conclude about the nature of P/2010 A2 from
Earth-based data only, as different scenarios lead to the same appearance in the orbital
configuration at the times of observations. We present here another set of images, acquired
from the unique viewing geometry provided by ESA’s Rosetta spacecraft [7] en
route to comet 67P/Churyumov-Gerasimenko. Albeit faint (22 magnitude/arcsec2),
the object could be observed by the high-resolution camera OSIRIS. We used a
Finson-Probstein model [3, 1] to simulate the shape of the trail, and estimate the time of
emission and β parameter (ratio between solar radiation pressure and gravity) for the
dust grains. Simulations were compared to the OSIRIS images and ground based
observations acquired at NTT and Palomar telescopes. Thanks to the different phase
angle provided by Rosetta, we could reduce the number of solutions to a unique
model, leading to the conclusive demonstration that the trail is not due to a period of
cometary activity but to a single event which took place on 10 February 2009 ± 5 days
[7].
References
[1]Â Â Â Beisser, K. & Böhnhardt, H. Evidence for the nucleus rotation in streamer
patterns of Comet Halley’s dust tail. Astrophysics and Space Science. 139, 5-12
(1987).
[2]Â Â Â Birtwhistle, P., Ryan, W. H., Sato, H., et al. Comet P/2010 A2 (LINEAR). IAU
Circular 9105 (2010).
[3]Â Â Â Finson, M. & Probstein, R. A theory of dust comets. 1. Model and equations.
Astrophy. J. 154, 327-380 (1968).
[4]Â Â Â Hsieh, H. H. & Jewitt, D. A population of comets in the main asteroid belt.
Science. 312, 561-563 (2006).
[5]Â Â Â Jewitt, D., Weaver, H., Agarwal, J., et al. A recent disruption of the main-belt
asteroid P/2010A2. Nature. 467, 817-819 (2010).
[6]Â Â Â Licandro, J., Tozzi, G. P., Liimets, et al. Comet P/2010 A2 (LINEAR). IAU
Circular 9109 (2010).
[7]Â Â Â Snodgrass, C., Tubiana, C., Vincent, J-B., et al. A collision in 2009 as the origin
of the debris trail of asteroid P/2010A2. Nature. 467, 814-816 (2010). |
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