The motion of chondrules and other particles in a protoplanetary disc with temperature fluctuations

Loesche, C.; Wurm, Gerhard; Kelling, T.; Teiser, Jens; Ebel, D. S.

doi:10.1093/mnras/stw2279

Cited by 7 publications

(4 citation statements)

References 56 publications

(65 reference statements)

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“…In protoplanetary disks, millimeter-sized particles usually collide at velocities below 1 m/s (Blum and Wurm, 2008). Their collision velocity might be increased one way or the other through the shocks, gas expansion or photophoresis, especially after a melting event (Wurm and Haack, 2009;Wurm et al, 2010;Loesche et al, 2016). It has generally been taken for granted that chondrules that collide at hot temperatures stick together even at collision velocities of 1 m/s (Kring, 1991;Ciesla et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Constraints on compound chondrule formation from laboratory high-temperature collisions

Bogdan¹,

Teiser²,

Fischer³

et al. 2019

Icarus

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In laboratory experiments, spherical 1 mm-wide glass and basalt particles are heated, and the hot particles collide at about 1 m/s with a flat glass target that is at room temperature. When the particles are heated below 900 K, the collisions are essentially elastic with coefficients of restitution of about 0.9, but above 900 K collisions become increasingly inelastic and the coefficient of restitution decreases with increasing temperature. At 1100 K the glass particles approach sticking but, simultaneously, at the same temperature the particles melt on timescales of minutes. The basalt particles approach sticking at 1200 K. Only above 1400 K do basalt grains in contact with each other fuse together, forming compounds on timescales of hours, and at 1500 K basalt grains completely fuse together. Therefore, cooling basalt grains only have a 100 K window for compound formation, and velocities very likely have to be below 1 m/s for sticking in the first place. We predict that this puts constraints on compound chondrule formation and particle densities in the solar nebula.

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Section: Introductionmentioning

confidence: 99%

Constraints on compound chondrule formation from laboratory high-temperature collisions

Bogdan¹,

Teiser²,

Fischer³

et al. 2019

Icarus

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“…Particle transport therefore either occurs in the inner part (gap) of the disc, or over the surface of the disk, albeit more effectively (Wurm & Haack 2009) than radiation pressure. However, thermal radiation in a disk with temperature fluctuations or radiation from a forming planet also induces photophoretic motion, which can lift and trap particles and might be important for chondrules being transported after they form (van Eymeren & Wurm 2012;Teiser & Dodson-Robinson 2013;Loesche et al 2016b;McNally & McClure 2017). Overall, photophoresis has been put on firm ground in recent years by experiments, and analytical models have been derived based on these experiments.…”

Section: Particle Transportmentioning

confidence: 99%

Understanding planet formation using microgravity experiments

Wurm

Teiser

2021

Nat Rev Phys

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In 2018, images were released of a planet being formed around the star PDS 70, offering a tantalizing glimpse into how planets come into being. However, many questions remain about how dust evolves into planets, and astrophysical observations are unable to provide all the answers. It is therefore necessary to perform experiments to reveal key details and, to avoid unwanted effects from the Earth's gravitational pull, it is often necessary to perform such experiments in microgravity platforms. This Review sketches current models of planet formation and describes the experiments needed to test the models.

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“…The problem with the optical thick inner part of protoplanetary disks might be bypassed by moving grains over the optical thin surface [107,108]. However, direct stellar radiation might not be the sole driver for photophoresis, e.g., Loesche et al [109] showed that temperature fluctuations, e.g., those witnessed by chondrule formation, lead to efficient photophoretic forces. McNally and Hubbard [110] investigated photophoresis in more detail in dense environments .…”

Section: Photophoresismentioning

confidence: 99%

Selective Aggregation Experiments on Planetesimal Formation and Mercury-Like Planets

Wurm¹

2018

Geosciences

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Much of a planet's composition could be determined right at the onset of formation. Laboratory experiments can constrain these early steps. This includes static tensile strength measurements or collisions carried out under Earth's gravity and on various microgravity platforms. Among the variety of extrasolar planets which eventually form are (Exo)-Mercury, terrestrial planets with high density. If they form in inner protoplanetary disks, high temperature experiments are mandatory but they are still rare. Beyond the initial process of hit-and-stick collisions, some additional selective processing might be needed to explain Mercury. In analogy to icy worlds, such planets might, e.g., form in environments which are enriched in iron. This requires methods to separate iron and silicate at early stages. Photophoresis might be one viable way. Mercury and Mercury-like planets might also form due to the ferromagnetic properties of iron and mechanisms like magnetic aggregation in disk magnetic fields might become important. This review highlights some of the mechanisms with the potential to trigger Mercury formation.

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The motion of chondrules and other particles in a protoplanetary disc with temperature fluctuations

Cited by 7 publications

References 56 publications

Constraints on compound chondrule formation from laboratory high-temperature collisions

Constraints on compound chondrule formation from laboratory high-temperature collisions

Understanding planet formation using microgravity experiments

Selective Aggregation Experiments on Planetesimal Formation and Mercury-Like Planets

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