Gravitational Instabilities in Circumstellar Disks

By K. Kratter, G. Lodato. 2016

361 citations recorded by the source corpus.

[Abridged] Star and planet formation are the complex outcomes of gravitational collapse and angular momentum transport mediated by protostellar and protoplanetary disks. In this review we focus on the role of gravitational instability in this process. We begin with a brief overview of the observational evidence for massive disks that might be subject to gravitational instability, and then highlight the diverse ways in which the instability manifests itself in protostellar and protoplanetary disks: the generation of spiral arms, small scale turbulence-like density fluctuations, and fragmentation of the disk itself. We present the analytic theory that describes the linear growth phase of the instability, supplemented with a survey of numerical simulations that aim to capture the non-linear evolution. We emphasize the role of thermodynamics and large scale infall in controlling the outcome of the instability. Despite apparent controversies in the literature, we show a remarkable level of agreement between analytic predictions and numerical results. We highlight open questions related to (1) the development of a turbulent cascade in thin disks, and (2) the role of mode-mode coupling in setting the maximum angular momentum transport rate in thick disks.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/5e1f985e8bfa2b1ee8d98caa9a6c66dee55b2fd5

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In Astronomy and Astrophysics

Citations in the corpus

On the diversity and statistical properties of protostellar discs (2018, background): “Kratter & Lodato (2016) provide a recent review of gravitational instabilities in circumstellar discs.”
Accretion onto Pre-Main-Sequence Stars (2016, background): “Mass and angular momentum transport by GI is discussed in detail in the review by Kratter & Lodato (2016).”
ALMA continuum observations of the protoplanetary disk AS 209. Evidence of multiple gaps opened by a single planet (2017, background): “Gravitational instability can occur on short timescales and is a viable process for the formation of giant planets on wide orbits (e.g., Kratter & Lodato 2016).”
The VLA/ALMA Nascent Disk and Multiplicity (VANDAM) Survey of Orion Protostars. II. A Statistical Characterization of Class 0 and Class I Protostellar Disks (2020, methodology): “Considering a simplified relationship for Toomre’s Q from Kratter & Lodato (2016), we can use the distribution of dust disk masses to infer which disks are most likely to be unstable with a few assumptions.”
The Close Binary Fraction of Solar-type Stars Is Strongly Anticorrelated with Metallicity (2018, background): “We require that the disk be able to radiate efficiently so that gravitational instability can lead to fragmentation, rather than gravitoturbulence or spiral mode saturation (Gammie 2001; Kratter & Lodato 2016).”
The Disk Substructures at High Angular Resolution Project (DSHARP). VI. Dust Trapping in Thin-ringed Protoplanetary Disks (2018, background): “…an upper bound on Σg by demanding that the disk is gravitationally stable, i.e. that the Toomre parameter obeys QToomre ≡ csΩK πGΣg > 2 (18) Otherwise non-axisymmetric features, such as spiral arms, would develop (see e.g. Kratter & Lodato 2016), which would also be seen in the continuum emission.”
FIRE-2 simulations: physics versus numerics in galaxy formation (2017, background): “27-28 show the results of turning on or off different portions of the cooling physics in our simulations.29 Specifically, we 29 For the m12i example in Fig.”
Super-Eddington Accretion Disks around Supermassive Black Holes (2017, background): “For example, density waves are commonly observed in disks with self-gravitational instability (Dong et al. 2015; Kratter & Lodato 2016), which also do not have a particular perturber at a fixed radius that may correspond to the pattern speed of the density waves.”
The Gemini Planet Imager Exoplanet Survey: Giant Planet and Brown Dwarf Demographics from 10 to 100 au (2019, background): “Brown dwarfs and perhaps also giant planets of the highest masses are thought to represent the low-mass outcome of the process by which stars form (i.e., gravitational instability; Forgan & Rice 2013; Kratter & Lodato 2016) or turbulent fragmentation (e.g., Hopkins 2013).”