Experiments on Preplanetary Dust Aggregation

Wurm, Gerhard; Blum, Jürgen

doi:10.1006/icar.1998.5891

Cited by 181 publications

(152 citation statements)

References 10 publications

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“…The interplanetary dust particles (IDPs) which are collected from the Earth's stratosphere by high-flying aircraft [1], [2] usually have irregular shapes and fluffy structures. Similar structures have been produced in laboratory and microgravity experiments of dust particle interactions [3], [4], [5]. It has also been suggested that interstellar dust grains may consist primarily of such aggregate structures [6], [7], with a mixture of various chemical compositions and vacuum.…”

Section: Introductionsupporting

confidence: 53%

Java application for the superposition T-matrix code to study the optical properties of cosmic dust aggregates

Halder¹,

Chakraborty²,

Roy³

et al. 2014

Computer Physics Communications

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In this paper, we report the development of a java application for the Superposition T-matrix code, JaSTA (Java Superposition Tmatrix App), to study the light scattering properties of aggregate structures. It has been developed using Netbeans 7.1.2, which is a java integrated development environment (IDE). The JaSTA uses double precession superposition codes for multi-sphere clusters in random orientation developed by Mackowski & Mischenko (1996). It consists of a graphical user interface (GUI) in the front hand and a database of related data in the back hand. Both the interactive GUI and database package directly enable a user to model by self-monitoring respective input parameters (namely, wavelength, complex refractive indices, grain size, etc.) to study the related optical properties of cosmic dust (namely, extinction, polarization, etc.) instantly, i.e., with zero computational time. This increases the efficiency of the user. The database of JaSTA is now created for a few sets of input parameters with a plan to create a large database in future. This application also has an option where users can compile and run the scattering code directly for aggregates in GUI environment. The JaSTA aims to provide convenient and quicker data analysis of the optical properties which can be used in different fields like planetary science, atmospheric science, nano science, etc. The current version of this software is developed for the Linux and Windows platform to study the light scattering properties of small aggregates which will be extended for larger aggregates using parallel codes in future. Program Summary:Program title: JaSTA: Java Superposition T-matrix App. Catalogue identifier: AETB v1 0 Program summary URL:

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Section: Introductionsupporting

confidence: 53%

Java application for the superposition T-matrix code to study the optical properties of cosmic dust aggregates

Halder¹,

Chakraborty²,

Roy³

et al. 2014

Computer Physics Communications

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“…This can be justified considering (1) the porous grains required to explain e.g. polarization maps of AU Mic (Graham et al 2007), and outcome from laboratory experiments of dust particle interactions (Wurm & Blum 1998); and (2) results from e.g. the β Pic model by Grigorieva et al (2007b) showing that any ∼1 mm sized grains at radial distances out to 150 AU would, due to photosputtering, be devoid of ice even though located beyond the snow-line.…”

Section: Spectral Energy Distribution and Disk Propertiesmentioning

confidence: 99%

A submillimetre search for cold extended debris disks in the $\mathsf{\beta}$ Pictoris moving group

Nilsson

Liseau

Brandeker

et al. 2009

A&A

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Context. Previous observations with the Infrared Astronomical Satellite and the Infrared Space Observatory, and ongoing observations with Spitzer and AKARI, have led to the discovery of over 200 debris disks, based on detected mid-and far infrared excess emission, indicating warm circumstellar dust. To constrain the properties of these systems, e.g., to more accurately determine the dust mass, temperature and radial extent, follow-up observations in the submillimetre wavelength region are needed. Aims. The β Pictoris moving group is a nearby stellar association of young (∼12 Myr) co-moving stars including the classical debris disk star β Pictoris. Due to their proximity and youth, they are excellent targets when searching for submillimetre emission from cold, extended, dust components produced by collisions in Kuiper-Belt-like disks. They also allow an age independent study of debris disk properties as a function of other stellar parameters. Methods. We observed 7 infrared-excess stars in the β Pictoris moving group with the LABOCA bolometer array, operating at a central wavelength of 870 μm at the 12-m submillimetre telescope APEX. The main emission at these wavelengths comes from large, cold dust grains, which constitute the main part of the total dust mass, and hence, for an optically thin case, make better estimates on the total dust mass than earlier infrared observations. Fitting the spectral energy distribution with combined optical and infrared photometry gives information on the temperature and radial extent of the disk. Results. From our sample, β Pic, HD 181327, and HD 172555 were detected with at least 3σ certainty, while all others are below 2σ and considered non-detections. The image of β Pic shows an offset flux density peak located near the south-west extension of the disk, similar to the one previously found by SCUBA at the JCMT. We present SED fits for detected sources and give an upper limit on the dust mass for undetected ones. Conclusions. We find a mean fractional dust luminosityf dust = 1.1 × 10 −3 at t ≈ 12 Myr, which together with recent data at 100 Myr suggests an f dust ∝ t −α decline of the emitting dust, with α > 0.8.

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“…Although physical details of aggregate collisions have been investigated experimentally (e.g. Wurm & Blum 1998, there are no measurements of triboelectrification in collisions of such aggregates. On a macroscopic scale, aggregates have other mechanical and thermal properties than single grains, and so the question arises as to what extent our results can be transferred to aggregate collisions.…”

Section: Application Recipe For Astrophysical Modelsmentioning

confidence: 99%

Further experiments on collisional tribocharging of cosmic grains

Poppe

Schräpler

2005

A&A

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Abstract. We experimentally investigated tribocharging in bouncing dust grain collisions under conditions which are relevant for the early solar nebula. We used silica, diamond, graphite, and silicon carbide grains and cm-sized targets of aluminum, iron, and graphite. We varied particle size around 1 µm, collision velocity between 38 to 106 m s −1 , and target temperature between 240 K and 360 K. Generally, the grains acquire something in the order of hundreds or thousands of negative elementary charges, which is at the upper end of the range previously discussed in astrophysical research. Mainly, a temperature difference caused by the dissipation of collisional energy or by initial temperatures determines the amount of charge transfer. It suggests a thermally diffusive charge transfer process of negative charge carriers. Nevertheless, also other processes of secondary importance were effective. Material-dependent contact charging is ruled out as the dominant charge transfer process in our experiments. For most particle-target combinations, the charge transfer can be described by an empirical function of collision energy which we propose for future astrophysical applications, especially for applications on the sticking efficiency in the preplanetary dust aggregation process, on the particle motion in the solar nebula, and on the possibility of nebular lightning.

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Experiments on Preplanetary Dust Aggregation

Cited by 181 publications

References 10 publications

Java application for the superposition T-matrix code to study the optical properties of cosmic dust aggregates

Java application for the superposition T-matrix code to study the optical properties of cosmic dust aggregates

A submillimetre search for cold extended debris disks in the $\mathsf{\beta}$ Pictoris moving group

Further experiments on collisional tribocharging of cosmic grains

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