Cometary dust trails

Sykes, M. V.; Walker, Russell G.

doi:10.1016/0019-1035(92)90037-8

Cited by 230 publications

(220 citation statements)

References 30 publications

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“…(3) The existence of large compact dust in the preimpact T1 coma has been reported by many researchers (Sykes & Walker 1992;Farnham et al 2007;Reach, Kelley, & Sykes 2007). The existence of such large dust in the preimpact T1 is consistent with the standard model, because the dust mantle formation depletes only fluffy aggregates.…”

Section: Introductionsupporting

confidence: 72%

Comet 9P/Tempel 1: Interpretation with theDeep ImpactResults

Yamamoto

Kimura

Zubko

et al. 2008

ApJ

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According to our common understandings, the original surface of a short-period comet nucleus has been lost by sublimation processes during its close approaches to the Sun. Sublimation results in the formation of a dust mantle on the retreated surface and in chemical differentiation of ices over tens or hundreds of meters below the mantle. In the course of NASA's Deep Impact mission, optical and infrared imaging observations of the ejecta plume were conducted by several researchers, but their interpretations of the data came as a big surprise: (1) The nucleus of comet 9P/Tempel 1 is free of a dust mantle but maintains its pristine crust of submicron-sized carbonaceous grains. (2) Primordial materials are accessible already at a depth of several tens of centimeters with abundant silicate grains of submicrometer sizes. In this study, we demonstrate that a standard model of cometary nuclei explains well available observational data: (1) A dust mantle with a thickness of ∼1-2 m builds up on the surface, where compact aggregates larger than tens of micrometers dominate. (2) Large fluffy aggregates are embedded in chemically differentiated layers as well as in the deepest part of the nucleus with primordial materials. We conclude that the Deep Impact results do not need any peculiar view of a comet nucleus.

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Section: Introductionsupporting

confidence: 72%

Comet 9P/Tempel 1: Interpretation with theDeep ImpactResults

Yamamoto

Kimura

Zubko

et al. 2008

ApJ

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“…The apparent resiliency of a number of fragments and the fact that fragment C continues to be in good health suggest that 73P is not yet a dying comet, contrary to recently expressed opinions in some magazines. One of the products of the process of cascading fragmentation is the formation of a dust trail, the phenomenon investigated for a number of periodic comets (e.g., Sykes & Walker 1992). The trail of coarse-grain and pebble-sized debris of 73P detected in the 218 Z. Sekanina infrared by the Spitzer Space Telescope † is apparently of the same nature as features observed in other split comets in the optical wavelengths, namely, a sheath of material in the sungrazer C/1882 R1 (e.g., Kreutz 1888) and a dust filament or trail in D/1993 F2 (e.g., Weaver et al .…”

Section: Current Return Of Comet 73p: a String Of Nucleus Fragmentsmentioning

confidence: 99%

Earth's 2006 encounter with comet 73P/Schwassmann-Wachmann: Products of nucleus fragmentation seen in closeup

Sekanina¹

2006

Proc. IAU

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Abstract. The large numbers of nucleus fragments observed are a spectacular illustration of the process of cascading fragmentation in progress, a concept introduced to interpret the properties of the Kreutz system of sungrazers and comet D/1993 F2. The objective is to describe the fragmentation sequence and hierarchy of comet 73P, the nature of the fragmentation process and observed events, and the expected future evolution of this comet. The orbital arc populated by the fragments refers to an interval of 3.74 days in the perihelion time. This result suggests that they all could be products (but not necessarily first-generation fragments) of two 1995 events, in early September (involving an enormous outburst) and at the beginning of November. The interval of perihelion times is equivalent to a range of about 2.5 m/s in separation velocity or 0.00012 the Sun's attraction in nongravitational deceleration. Their combined effect suggests minor orbital momentum changes acquired during fragmentation and decelerations compatible with survival over two revolutions about the Sun. Fragment B is a likely first-generation product of one of the 1995 events. From the behavior of the primary fragment C, 73P is not a dying comet, even though fragment B and others were episodically breaking up into many pieces. Each episode began with the sudden appearance of a starlike nucleus condensation and a rapidly expanding outburst, followed by a development of jets, and a gradual tailward extension of the fading condensation, until the discrete masses embedded in it could be resolved. In April-May, this debris traveled first to the southwest, but models show their eventual motion toward the projected orbit. Fainter fragments were imaged over limited time, apparently because of their erratic activity (interspersed with periods of dormancy) rather than improptu disintegration. A dust trail joining the fragments and reminiscent of comet 141P/Machholz suggests that cascading fragmentation exerts itself profoundly over an extremely broad mass range of particulate debris.

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“…The IRAS satellite detected a dust trail for 9P/Tempel 1 (Sykes & Walker 1992), however, no optical trail has been found so far for 9P/Tempel 1. Knowledge of the dust distribution in the trail for 9P/Tempel 1, i.e.…”

Section: Features In the Dust Comamentioning

confidence: 84%

The Deep Impact Earth-Based Campaign

et al. 2005

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Prior to the selection of the comet 9P/Tempel 1 as the Deep Impact mission target, the comet was not well-observed. From 1999 through the present there has been an intensive world-wide observing campaign designed to obtain mission critical information about the target nucleus, including the nucleus size, albedo, rotation rate, rotation state, phase function, and the development of the dust and gas coma. The specific observing schemes used to obtain this information and the resources needed are presented here. The Deep Impact mission is unique in that part of the mission observations will rely on an Earth-based (ground and orbital) suite of complementary observations of the comet just prior to impact and in the weeks following. While the impact should result in new cometary activity, the actual physical outcome is uncertain, and the Earth-based observations must allow for a wide range of post-impact phenomena. A world-wide coordinated effort for these observations is described.

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Cometary dust trails

Cited by 230 publications

References 30 publications

Comet 9P/Tempel 1: Interpretation with theDeep ImpactResults

Comet 9P/Tempel 1: Interpretation with theDeep ImpactResults

Earth's 2006 encounter with comet 73P/Schwassmann-Wachmann: Products of nucleus fragmentation seen in closeup

The Deep Impact Earth-Based Campaign

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