Numerical simulations of protostellar encounters - II. Coplanar disc-disc encounters

Watkins, S. J.; Bhattal, A. S.; Boffin, H. M. J.; Francis, N.; Whitworth, Anthony Peter

doi:10.1046/j.1365-8711.1998.t01-1-01987.x

Cited by 19 publications

(30 citation statements)

References 20 publications

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“…A full understanding of disk-disk interactions await extensive numerical studies, which are only beginning to appear (e.g. Watkins et al 1998).…”

Section: Disk-disk Interactions and Giant Hh Bow Shocksmentioning

confidence: 99%

Outflows from Newborn Multiple Stars

Reipurth

2001

Symp. - Int. Astron. Union

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Abstract. Analysis of a sample of giant Herbig-Haro flow sources shows that 79% -86% are binaries or higher order multiples. This represents the youngest sample of stars studied so far for binarity. A stellar dynamics jet hypothesis is proposed in which the dynamical decay of triple or multiple systems leads to giant outflow activity. Close triple approaches will cause serious perturbations and probably direct collisions among individual circumstellar disks, with a consequent burst of outflow activity, which can produce giant HH bow shocks. As one component is ejected, the two remaining stars and their small truncated disks form a -closer bound pair with high eccentricity. Gas streams from a circumbinary disk feed the stars and this as well as other dynamical effects cause the binary orbit to shrink. As the stellar components gradually spiral towards each other, accretion and outflow becomes cyclic, modulated on an orbital time scale. The resulting HH flows can be read as a fossil record of the evolution of orbital motions of the newly formed binary as it shrinks from a typical separation of 100 AU or more to 10 AU or less. After a triple disintegration event, both components (star and close binary) leave their nascent envelope, and while one component becomes visible as a T Tauristar, the other will be obscured for a while by the envelope and will appear as a bright near-infrared object, thus explaining the socalled IRC binaries which are infrequently found in star forming regions.

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“…A full understanding of disk-disk interactions await extensive numerical studies, which are only beginning to appear (e.g. Watkins et al 1998).…”

Section: Disk-disk Interactions and Giant Hh Bow Shocksmentioning

confidence: 99%

Outflows from Newborn Multiple Stars

Reipurth

2001

Symp. - Int. Astron. Union

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“…One issue that has gained surprisingly little attention in the past is the role of gravitational interactions between the disk and passing stars within the young host stellar cluster. Since stars are generally born in clusters (Forgan & Rice 2009), rather than as isolated objects, star-disk and disk-disk interactions (Boffin et al 1998;Watkins et al 1998a;Pfalzner et al 2005;Thies et al 2005) probably play an important role for the dynamical evolution of such disks and thus for massive planet and BD formation through fragmentation of the disks.…”

Section: Introductionmentioning

confidence: 99%

“…Most of these investigations, however, assume that the disk evolves in isolation. Star-disk and disk-disk collisions have been investigated in previous studies (Boffin et al 1998;Watkins et al 1998aWatkins et al , 1998b but without a realistic treatment of the radiative heat transfer in the disk. From smoothed particle hydrodynamic (SPH) computations, Forgan & Rice (2009) deduce that close encounters inhibit fragmentation in typical protoplanetary disks (assuming an initial radius of 40 AU) rather than inducing it.…”

Section: Introductionmentioning

confidence: 99%

Tidally Induced Brown Dwarf and Planet Formation in Circumstellar Disks

Thies

Kroupa

Goodwin

et al. 2010

ApJ

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Most stars are born in clusters and the resulting gravitational interactions between cluster members may significantly affect the evolution of circumstellar disks and therefore the formation of planets and brown dwarfs (BDs). Recent findings suggest that tidal perturbations of typical circumstellar disks due to close encounters may inhibit rather than trigger disk fragmentation and so would seem to rule out planet formation by external tidal stimuli. However, the disk models in these calculations were restricted to disk radii of 40 AU and disk masses below 0.1 M . Here, we show that even modest encounters can trigger fragmentation around 100 AU in the sorts of massive (∼0.5 M ), extended ( 100 AU) disks that are observed around young stars. Tidal perturbation alone can do this; no disk-disk collision is required. We also show that very low mass binary systems can form through the interaction of objects in the disk. In our computations, otherwise non-fragmenting massive disks, once perturbed, fragment into several objects between about 0.01 and 0.1 M , i.e., over the whole BD mass range. Typically, these orbit on highly eccentric orbits or are even ejected. While probably not suitable for the formation of Jupiter-or Neptune-type planets, our scenario provides a possible formation mechanism for BDs and very massive planets which, interestingly, leads to a mass distribution consistent with the canonical substellar initial mass function. As a minor outcome, a possible explanation for the origin of misaligned extrasolar planetary systems is discussed.

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“…Clarke & Pringle (1991) approached the question of binary formation due to star-disk encounters analytically, while Ostriker (1994) analytically treated the case of more distant encounters. Watkins et al (1998aWatkins et al ( , 1998b performed SPH simulations of encounters in which both stars have circumstellar disks. Of the numerical studies dealing with close encounters, none considers stellar mass ratios m 2 /m 1 < 0:5, and Hall (1997) and Pfalzner (2004) are the only studies that consider repeated encounters.…”

Section: Introductionmentioning

confidence: 99%

Stellar Encounters with Massive Star‐Disk Systems

Moeckel

Bally

2006

ApJ

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The dense, clustered environment in which massive stars form can lead to interactions with neighboring stars. It has been hypothesized that collisions and mergers may contribute to the growth of the most massive stars. In this paper we extend the study of star-disk interactions to explore encounters between a massive protostar and a less massive cluster sibling using the publicly available SPH code GADGET-2. Collisions do not occur in the parameter space studied, but the end state of many encounters is an eccentric binary with a semimajor axis $100 AU. Disk material is sometimes captured by the impactor. Most encounters result in disruption and destruction of the initial disk and periodic torquing of the remnant disk. We consider the effect of the changing orientation of the disk on an accretiondriven jet and the evolution of the systems in the presence of on-going accretion from the parent core.

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Numerical simulations of protostellar encounters - II. Coplanar disc-disc encounters

Cited by 19 publications

References 20 publications

Outflows from Newborn Multiple Stars

Outflows from Newborn Multiple Stars

Tidally Induced Brown Dwarf and Planet Formation in Circumstellar Disks

Stellar Encounters with Massive Star‐Disk Systems

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