Finite lifetime fragment model for synchronic band formation in dust tails of Comets

Nishioka, Kimihiko; Watanabe, J.

doi:10.1016/0019-1035(90)90143-w

Cited by 15 publications

(7 citation statements)

References 8 publications

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“…Dust tail striae are thought to form through the fragmentation of dust agglomerates [Sekanina andFarrell, 1980, 1982;Hill and Mendis, 1980;Notni and Thaenert, 1988;Nishioka and Watanabe, 1990;Pittichová et al, 1997]. The escaping gases drag ice-mixed dust forming a strongly coupled ensemble in the vicinity of the nucleus, which then decouple as they expand farther out leaving the several hundreds of m s −1 fast icy conglomerates exposed to the solar conditions (solar heat, electrostatic charging, collisions, etc.)…”

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confidence: 99%

Dynamics of HVECs emitted from comet C/2011 L4 as observed by STEREO

et al. 2015

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High-quality white-light images from the Sun-Earth Connection Coronal and Heliospheric Investigation (SECCHI) HI-1 telescope on board STEREO-B reveal high-velocity evanescent clumps (HVECs) expelled from the coma of the C/2011 L4 (Pan-STARRS) comet. The observations were recorded around the comet's perihelion (i.e., ∼0.3 AU) during the period 9-16 March 2013. Animated images provide evidence of highly dynamic ejecta moving near radially in the antisunward direction. The bulk speed of the clumps at their initial detection in the HI1-B images range from 200 to 400 km s −1 followed by an appreciable acceleration up to speeds of 450-600 km s −1 , which are typical of slow to intermediate solar wind speeds. The clump velocities do not exceed these limiting values and seem to reach a plateau. The images also show that the clumps do not expand as they propagate. The white-light images do not provide direct insight into the composition of the expelled clumps, which could potentially be composed of fine, submicron dust particles, neutral atoms and molecules, and/or ionized atomic/molecular cometary species. Although solar radiation pressure plays a role in accelerating and size sorting of small dust grains, it cannot accelerate them to velocities >200 km s −1 in the observed time interval of a few hours and distance of <10 6 km. Further, order of magnitude calculations show that ionized single atoms or molecules accelerate too quickly compared to observations, while dust grains micron sized or larger accelerate too slowly. We find that neutral Na, Li, K, or Ca atoms with > 50 could possibly fit the observations. Just as likely, we find that an interaction with the solar wind and the heliospheric magnetic field can cause the observed clump dynamical evolution, accelerating them quickly up to solar wind velocities. We thus speculate that the HVECs are composed of charged particles (dust particles) or neutral atoms accelerated by radiation pressure at > 50 values. In addition, the data suggest that clump ejecta initially move along near-radial, bright structures, which then separate into HVECs and larger dust grains that steadily bend backward relative to the comet's orbital motion due to the effects of solar radiation and gravity. These structures gradually form new striae in the dust tail. The near-periodic spacing of the striae may be indicative of outgassing activity modulation due to the comet nucleus' rotation. It is, however, unclear whether all striae are formed as a result of this process.

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confidence: 99%

Dynamics of HVECs emitted from comet C/2011 L4 as observed by STEREO

et al. 2015

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“…This provides a good match to observational data (Pittichová et al, 1997), but the required physical properties of dust are difficult to explain. Nishioka and Watanabe (1990), Nishioka (1998) and Nishioka (2021) instead suggest a continuous cascade of striae formation, which relaxes the constraints on dust properties, but has alleged problems explaining stria shapes (Sekenina and Pittichová, 1997). Other potential mechanisms include optically thick dust clouds (Froehlich and Notni, 1988;Notni and Thaenert, 1988), or the destruction of macroscopic sized (10-100 m) boulders by rotational stresses (Steckloff and Jacobson, 2016).…”

Section: Striae Formation Theoriesmentioning

confidence: 99%

Fine-scale structure in cometary dust tails II: Further evidence for a solar wind influence on cometary dust dynamics from the analysis of striae in comet C/2011 L4 Pan-STARRS

Price

Jones

Battams

et al. 2023

Icarus

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“…Пiзнiше всi батькiвськi частки фрагментують в один i той же час на вiдстанях аж до декiлькох мiльйонiв кiлометрiв. Пiзнiше ця модель була застосована до комет C/1957 P1 (Mrkos) [19], C/1962 C1 (Seki-Lines) [10] та C/1910 A1 (Great January Comet) [18]. Необхiднiсть раптового одночасного розпаду батькiвських частинок є головним вразливим мiсцем даної моделi.…”

Section: вступunclassified

The formation of striated structures in dust tails of comets

Kharchuk

Корсун

2012

AstSR

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The mechanism of formation of striae structures in the dust tails of comets is proposed. There are local active areas on the surfaces of comet nucleus. The formation of striae is indebted to the different rate of dust ejection from active areas depending on that they are located on the sunlit or shaded side of the rotating nucleus. The model analysis of dust tails forming of comets C/1957 P1 (Mrkos), C/1962 C1 (Seki-lines), C/1910 A1 (Great January Comet), C/1975 V1 (West) showed that the proposed mechanism can explain the formation of striae. Ключевые слова: кометная пыль; активность ядер комет.

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Finite lifetime fragment model for synchronic band formation in dust tails of Comets

Cited by 15 publications

References 8 publications

Dynamics of HVECs emitted from comet C/2011 L4 as observed by STEREO

Dynamics of HVECs emitted from comet C/2011 L4 as observed by STEREO

Fine-scale structure in cometary dust tails II: Further evidence for a solar wind influence on cometary dust dynamics from the analysis of striae in comet C/2011 L4 Pan-STARRS

The formation of striated structures in dust tails of comets

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