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Title: An early look of comet C/2013 A1 (Siding Spring): Breathtaker or nightmare?

The dynamically new comet, C/2013 A1 (Siding Spring), is to make a close approach to Mars on 2014 October 19 at 18:30 UT at a distance of 40 ± 1 Martian radii. Such an extremely rare event offers a precious opportunity for the spacecrafts on Mars to closely study a dynamically new comet itself as well as the planet-comet interaction. Meanwhile, the high-speed meteoroids released from C/Siding Spring also pose a threat to physically damage the spacecrafts. Here we present our observations and modeling results of C/Siding Spring to characterize the comet and assess the risk posed to the spacecrafts on Mars. We find that the optical tail of C/Siding Spring is dominated by larger particles at the time of the observation. Synchrone simulation suggests that the comet was already active in late 2012 when it was more than 7 AU from the Sun. By parameterizing the dust activity with a semi-analytic model, we find that the ejection speed of C/Siding Spring is comparable to comets such as the target of the Rosetta mission, 67P/Churyumov-Gerasimenko. Under a nominal situation, the simulated dust cone will miss the planet by about 20 Martian radii. At the extreme ends of uncertainties, the simulatedmore » dust cone will engulf Mars, but the meteoric influx at Mars is still comparable to the nominal sporadic influx, seemly indicating that an intense and enduring meteoroid bombardment due to C/Siding Spring is unlikely. Further simulation also suggests that gravitational disruption of the dust tail may be significant enough to be observable at Earth.« less
Authors:
 [1] ;  [2]
  1. Department of Physics and Astronomy, The University of Western Ontario, London, Ontario N6A 3K7 (Canada)
  2. Nhut Thung Pau Observatory, Guangzhou (China)
Publication Date:
OSTI Identifier:
22356788
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 787; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COMETS; COMPARATIVE EVALUATIONS; DAMAGE; DISTANCE; DUSTS; INTERACTIONS; MARS PLANET; METEORITES; METEOROIDS; SATELLITES; SIMULATION; SUN; VELOCITY