Cometary splitting due to thermal stresses

Тамбовцева, Л. В.; Шестакова, Л. И.

doi:10.1016/s0032-0633(98)00143-3

Cited by 23 publications

(17 citation statements)

References 16 publications

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“…Of course, when it later becomes a star-grazer, these processes can play a significant role (Tambovtseva & Shestakova 1999), especially in a hotter environment than the Sun, as is the case here (Grinin et al 1996). This is beyond the scope of the present study.…”

Section: General Assumptionsmentioning

confidence: 64%

The physico-chemical history of Falling Evaporating Bodies aroundβPictoris: investigating the presence of volatiles

Karmann

Beust

Klinger

2001

A&A

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Abstract. Transient spectral absorption events have been monitored for many years toward the star β Pictoris and have been interpreted as resulting from the transit across the line of sight of evaporating comet-sized bodies (Falling Evaporating Bodies, or FEBs). The model shows that these bodies come from circular orbits at > ∼ 4 AU, becoming star-grazers due to planetary perturbations. The physics of the evaporation of those bodies is widely influenced by their physico-chemical properties, especially the presence of volatile matter. We investigate here this question from a modeling point of view, adapting for that case the models designed for solar comets. We simulate the physico-chemical evolution of the FEB progenitors on circular orbits for a time comparable to the supposed age of β Pic, and constrain the quantity of volatiles present in them in relationship with its age and to the semi-major axis of the orbits. We also constrain this semi-major axis by investigating its influence on the dynamical model of FEB generation by planetary perturbations, and show that it is probably less than ∼10 AU. Finally, we show that demanding the FEB progenitors to be icy in a major part of their volume at those distances is probably an unrealistic constraint, and that they more likely look like asteroids with perhaps a small icy nucleus rather than fully icy comets. This result leads to a revision of the FEB evaporation model that has been assumed up to now.

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Section: General Assumptionsmentioning

confidence: 64%

The physico-chemical history of Falling Evaporating Bodies aroundβPictoris: investigating the presence of volatiles

Karmann

Beust

Klinger

2001

A&A

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“…(A.1) to the dipole and higherorder terms only, ignoring the monopole n = 0. This is because the monopole part would correspond to purely radial temperature field, such as has been considered, for instance, in the previous works on our topic (e.g., Kuehrt 1984;Shestakova & Tambovtseva 1997;Tambovtseva & Shestakova 1999). Our temperature representation T = T av + ΔT does not contain a nontrivial, purely radial profile 10 and the only viable free monopole term must have U 00 = W 00 = 0 to match the boundary conditions.…”

Section: Appendix A: Solution Of the Duhamel-neumann Equationmentioning

confidence: 94%

“…Their importance to the evolution of cometary nuclei was advocated and discussed, for example, by Kuehrt (1984), Tauber & Kuhrt (1987), and Tambovtseva & Shestakova (1999). In their view, as the cometary nucleus approaches the Sun, the thermal stresses may become several orders of magnitude larger then the estimated solar tidal stresses.…”

Section: Introductionmentioning

confidence: 99%

“…While the previous analyses of Kuehrt (1984), Shestakova & Tambovtseva (1997), and Tambovtseva & Shestakova (1999) considered the time dependence of the temperature field caused by the approach to the Sun along a parabolic orbit, they adopted significant simplifications that our approach attempts to remove. Most importantly, they (i) circumvented the difficulty in solving the thermal boundary condition by assuming exact equilibrium between the incident solar flux and thermal emission (neglecting heat conduction into the body); and (ii) assumed only a radial temperature dependence (neglecting the latitudinal and longitudinal dependence related to the specific location of the Sun).…”

Section: Introductionmentioning

confidence: 99%

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Thermal stresses in small meteoroids

Čapek

Vokrouhlický

2010

A&A

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Aims. We evaluate thermal stresses in small, spherical, and homogeneous meteoroids with elastic rheology and regular rotation. The temperature variations are caused by the absorbed sunlight energy being conducted into the interior layers of the body. Our model assumes arbitrary thermal conductivity value, but restricts itself to a linearized treatment of the boundary conditions of the heat diffusion problem. We consider the diurnal insolation cycle only as if the body were in a fixed position along its heliocentric orbit. This constrains the upper limit to the object size to which our modeling is applicable. Methods. We derive analytical expressions for the components of the thermal stress tensor throughout the body. Using two sets of material properties (ordinary and carbonaceous chondrites), we study the conditions required for material failure caused by thermal stress leading to fission. Results. Our results indicate that the onset of thermal failure in the meteoroid depends on a number of parameters including the heliocentric distance, the size, the rotation frequency, and the orientation of the spin axis with respect to the solar direction. In our case, we find large, centimeter-to meter-size, slowly rotating meteoroids or those with a spin axis pointing towards the Sun or both, are the most susceptible to the thermal bursting. This may have implications for the (i) size distribution of meteoroids in various streams depending on their heliocentric orbit and the physical characteristics of their parent bodies; (ii) orbital distribution of sporadic complexes of meteoroids in the planet-crossing zone; and/or (iii) fate of fragments released during comet disintegration events, especially those with low perihelia (e.g., Kreutz class).

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“…The exposure of new undersurface layers can be a result of thermal stresses in the cometary nucleus which can lead to a formation of cracks, crevices and deep rift on its surface. Indeed, the thermal stresses can be the cause of the destruction of the undersurface layers of the nucleus to the depth of several metres (Kührt 1984;Tambovtseva & Shestakova 1999). In this way the reaction of polymerization may reach the deeper regions of the nucleus where amorphous water ice could survive.…”

Section: The Polymerization Of Hcnmentioning

confidence: 99%

The search for a cometary outbursts mechanism: a comparison of various theories

Gronkowski

2007

Astron Nachr

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In the paper the potential sources of energy of cometary outbursts have been reviewed. Considerations focus on four probable sources of the outbursts' energy. These are the polymerization of hydrogen cyanide HCN, impacts with the meteoroids, destruction of cometary grains in the field of strong solar wind and the transformation of amorphous water ice into the crystalline one. The values of released energy and jumps of cometary brightness caused by these mechanisms have been discussed. A modern approach to the problem of the thermodynamical evolution of the comet nucleus which includes amorphous water ice is considered as the starting point in the discussion presented in the paper. The main characteristics of an outburst of a hypothetical comet belonging to the Jupiter family comet are calculated. The obtained results are in a good agreement with the characteristics observed during the real outbursts of comets. The main conclusion of this paper confirms a general presumption that the cometary outbursts can have different causes. However, the hypothesis concerning the amorphous water ice transformation appears to be the most probable one.

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Cometary splitting due to thermal stresses

Cited by 23 publications

References 16 publications

The physico-chemical history of Falling Evaporating Bodies aroundβPictoris: investigating the presence of volatiles

The physico-chemical history of Falling Evaporating Bodies aroundβPictoris: investigating the presence of volatiles

Thermal stresses in small meteoroids

The search for a cometary outbursts mechanism: a comparison of various theories

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