Early evolution of the birth cluster of the solar system

Pfalzner, Susanne

doi:10.1051/0004-6361/201218792

Cited by 90 publications

(75 citation statements)

References 70 publications

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“…This change was already noticed in the context of the influence of encounters on protoplanetary discs (Olczak et al 2010;Duke & Krumholz 2012;Olczak et al 2012;Pfalzner 2013). It was found there that parabolic encounters with low-mass stars (<0.5 M ) and the few most massive stars of the system dominate at mean cluster densities of ≈10 3 pc −3 .…”

Section: Nature Of the Encounter-induced Mass Lossmentioning

confidence: 68%

Reaction of massive clusters to gas expulsion – The cluster density dependence

Pfalzner

Kaczmarek

2013

A&A

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Context. The expulsion of the unconverted gas at the end of the star formation process potentially leads to the expansion of the just formed stellar cluster and membership loss. The degree of expansion and mass loss depends largely on the star formation efficiency and scales with the mass and size of the stellar group when stellar interactions can be neglected. Aims. We investigate the circumstances in which stellar interactions between cluster members become so important that the fraction of bound stars after gas expulsion is significantly altered. Methods. The Nbody6 code is used to simulate the cluster dynamics after gas expulsion for different star formation efficiences. Concentrating on the most massive clusters observed in the Milky Way, we test to what extent the results depend on the model, i.e. stellar mass distribution, stellar density profile etc., and the cluster parameters, such as cluster density and size. Results. We find that stellar interactions leading to ejections are responsible for up to 20% mass loss in the most compact massive clusters in the Milky Way. Therefore, ejections are the prime mass loss process in these systems. Even in the loosely bound OB associations, stellar interactions are responsible for at least ∼5% mass loss. The main reason why the importance of encounters for massive clusters has been largely overlooked is because of the often used approach of a single-mass representation instead of a realistic distribution for the stellar masses. The density dependence on the encounter-induced mass loss is shallower than expected because of the increasing importance of few-body interactions in dense clusters compared to sparse clusters where 2-body encounters dominate.

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Section: Nature Of the Encounter-induced Mass Lossmentioning

confidence: 68%

Reaction of massive clusters to gas expulsion – The cluster density dependence

Pfalzner

Kaczmarek

2013

A&A

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“…Unfortunately, this result for an encounter between equal-mass stars has been applied in a number of studies (Adams et al 2006;Adams 2010;Malmberg et al 2011;Jiménez-Torres et al 2011;Pfalzner 2013;Rosotti et al 2014) to non-equal mass encounters where it is not valid (Breslau et al 2014). Pfalzner et al (2005b) investigated the dependence of the disk size on the mass ratio for the case of a parabolic, coplanar, prograde encounter at different periastron distances.…”

Section: Introductionmentioning

confidence: 99%

Effects of inclined star-disk encounter on protoplanetary disk size

Bhandare

Breslau

Pfalzner

2016

A&A

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Most, if not all, young stars are initially surrounded by protoplanetary disks. Owing to the preferential formation of stars in stellar clusters, the protoplanetary disks around these stars may potentially be affected by the cluster environment. Various works have investigated the influence of stellar fly-bys on disks, although many of them consider only the effects due to parabolic, coplanar encounters often for equal-mass stars, which is only a very special case. We perform numerical simulations to study the fate of protoplanetary disks after the impact of parabolic star-disk encounter for the less investigated case of inclined up to coplanar, retrograde encounters, which is a much more common case. Here, we concentrate on the disk size after such encounters because this limits the size of the potentially forming planetary systems. In addition, with the possibilities that ALMA offers, now a direct comparison to observations is possible. Covering a wide range of periastron distances and mass ratios between the mass of the perturber and central star, we find that despite the prograde, coplanar encounters having the strongest effect on the disk size, inclined and even the least destructive retrograde encounters mostly also have a considerable effect, especially for close periastron passages. Interestingly, we find a nearly linear dependence of the disk size on the orbital inclination for the prograde encounters, but not for the retrograde case. We also determine the final orbital parameters of the particles in the disk such as eccentricities, inclinations, and semi-major axes. Using this information the presented study can be used to describe the fate of disks and also that of planetary systems after inclined encounters.

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“…Nevertheless, the above results are often generalised as encounters truncating discs to 1/2-1/3 of the periastron distance (e.g. Brasser et al 2006;Adams et al 2006;Adams 2010;Jiménez-Torres et al 2011;Malmberg et al 2011;Pfalzner 2013). There the dependence of the disc truncation on the mass of the perturbing star and other geometrical properties of the perturber orbit are disregarded.…”

Section: Introductionmentioning

confidence: 99%

Sizes of protoplanetary discs after star-disc encounters

Breslau

Steinhausen

Vincke

et al. 2014

A&A

140

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Most stars do not form in isolation, but as part of a star cluster or association. These young stars are initially surrounded by protoplanetary discs. In these cluster environments tidal interactions with other cluster members can alter the disc properties. Besides the disc frequency, its mass, angular momentum, and energy, the disc's size is particularly prone to being changed by a passing star. So far the change in disc size has only been investigated for a small number of very specific encounters. Several studies investigated the effect of the cluster environment on the sizes of planetary systems like our own solar system, based on a generalisation of information from this limited sample. We performed numerical simulations covering the wide parameter space typical of young star clusters, to test the validity of this approach. Here the sizes of discs after encounters are presented, based on a size definition that is comparable to the one used in observational studies. We find that, except for encounters between equal-mass stars, the usually applied estimates are insufficient. They tend to severely overestimate the remaining disc size. We show that the disc size after an encounter can be described by a relatively simple dependence on the periastron distance and the mass ratio of the encounter partners. This knowledge allows us, for example, to pin down the types of encounter possibly responsible for the structure of today's solar system.

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Early evolution of the birth cluster of the solar system

Cited by 90 publications

References 70 publications

Reaction of massive clusters to gas expulsion – The cluster density dependence

Reaction of massive clusters to gas expulsion – The cluster density dependence

Effects of inclined star-disk encounter on protoplanetary disk size

Sizes of protoplanetary discs after star-disc encounters

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