Cometary outbursts - search of probable mechanisms - case of 29P/Schwassmann-Wachmann 1

Monthly Notices of the Royal Astronomical Society: Letters

2007

Self Cite

In this Letter the mechanism of destruction of ice grains as the cause of cometary outbursts and variations of brightness is reviewed. Such destruction can arise from the combination of two causes: inclusions of chemical compounds that are much more volatile than water‐ice placed inside cometary water‐ice grains; and the influence of the solar wind on such heterogeneous grains. Numerical calculations have been carried out for a large range of values of probable physical characteristics of cometary material. This approach gives a simulated increase in the cometary brightness that is consistent with the observed one. It is concluded that this mechanism is a probable and real explanation of the sudden activity of comets at a wide range of heliocentric distances.

Section: The Thermodynamical Fragmentation Of Cometary Ice Grainssupporting

confidence: 73%

Section: The Electrostatic Destruction Of Cometary Ice Grainsmentioning

confidence: 99%

A model of cometary outbursts based on the idea of fragmentation of ice grains

Monthly Notices of the Royal Astronomical Society: Letters

2007

Self Cite

“…Then the total electrostatic energy of cometary charged grains is equal E tot = N g × E el , where N g denotes a total number of charged grains in the head of a comet. In order to estimate the value of N g , we proceed in a similar way as in the paper by Gronkowski (2002). For the Comet 29P/SchwassmannWachmann 1 the value of E tot obtained in this way varies from ∼ 10 9 J to ∼ 10 11 J when a parameter η which describes the active sublimation part of the surface of the cometary nucleus varies from 0.1% to 10%.…”

Section: Fragmentation and Destruction Of The Cometary Grainsmentioning

confidence: 99%

“…The simulated changes of the brightness of the comet were calculated in a similar way as in the papers by Gronkowski & Smela (1998) and Gronkowski (2002Gronkowski ( , 2004aGronkowski ( , 2004b, and for that reason only the formula for ∆m is presented here:…”

Section: The Jump Of the Brightness Of A Cometmentioning

confidence: 99%

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

2007

Astron Nachr

Self Cite

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.

“…We can observe the increase in the brightness of the comet as the consequence of this fact. This mechanism adapted to SW1 gives the amplitude of the jump in the brightness of this comet as −1.15 mag at the very most (Gronkowski 2002a). This hypothesis strictly connects the outbursts of SW1 with solar activity.…”

Section: Energy For Sw1 Outbursts – Hypotheses Published In the Pasmentioning

confidence: 99%

The source of energy of the comet 29P/Schwassmann-Wachmann 1 outburst activity: the test of the summary

Monthly Notices of the Royal Astronomical Society

2005

Self Cite

The comet 29P/Schwassmann‐Wachmann 1 is an exceptional comet as far as cometary outbursts are concerned. Despite its large distance from the Sun (about 6 au), it shows quasi‐regular outburst activity, usually once or twice a year. Up to now there has not been a generally accepted model that explains this phenomenon. In the first part of this paper, the most well‐known hypotheses that attempt to explain the outburst activity of this comet are presented and critically analysed. The main aim of this paper is to present a model for the outburst activity of this comet. The model is based on the global analysis of the internal structure and physical and chemical processes that take place in the cometary nucleus. Numerical calculations were carried out for reasonable assumed values of a large range of cometary characteristics. The obtained results are consistent with observational data.