The Gravitational Instability of Adiabatic Filaments

Coughlin, Eric R.; Nixon, Chris

doi:10.3847/1538-4365/ab77c2

Cited by 26 publications

(15 citation statements)

References 50 publications

(62 reference statements)

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“…More recently we have shown that the late-time fallback rate power-law index (n ∞ ) for a partial TDE-in which the star is not fully disrupted and some of the star remains intact-is ≈ −9/4, and not −5/3 (Coughlin & Nixon 2019). This value is almost completely independent of the mass fraction of the surviving core, µ = M c /M • , where M c is the mass of the surviving core and M • is the mass of the black hole (see Equation 14of Coughlin & Nixon 2019). This arises from the fact that the debris that returns at late times originates asymptotically close to the Hill's radius-the region surrounding the core in which the core's gravity dominates over that of the black hole-of the surviving core, and thus is always affected by the core's gravity for any (non-zero) mass.…”

Section: Introductionmentioning

confidence: 99%

Partial, zombie, and full tidal disruption of stars by supermassive black holes

Nixon,

Coughlin,

Miles

2021

Preprint

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We present long-duration numerical simulations of the tidal disruption of stars modelled with accurate stellar structures and spanning a range of pericentre distances, corresponding to cases where the stars are partially and completely disrupted. We substantiate the prediction that the late-time power-law index of the fallback rate n ∞ −5/3 for full disruptions, while for partial disruptions-in which the central part of the star survives the tidal encounter intact-we show that n ∞ −9/4. For the subset of simulations where the pericenter distance is close to that which delineates full from partial disruption, we find that a stellar core can reform after the star has been completely destroyed; for these events the energy of the zombie core is slightly positive, which results in late-time evolution from n −9/4 to n −5/3. We find that self-gravity can generate an n(t) that deviates from n ∞ by a small but significant amount for several years post-disruption. In one specific case with the stellar pericenter near the critical value, we find self-gravity also drives the re-collapse of the central regions of the debris stream into a collection of several cores while the rest of the stream remains relatively smooth. We also show that it is possible for the surviving stellar core in a partial disruption to acquire a circumstellar disc that is shed from the rapidly rotating core. Finally, we provide a novel analytical fitting function for the fallback rates that may also be useful in a range of contexts beyond TDEs.

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Section: Introductionmentioning

confidence: 99%

Partial, zombie, and full tidal disruption of stars by supermassive black holes

Nixon,

Coughlin,

Miles

2021

Preprint

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“…The Kepler mission discovered 4723 exoplanet candidates, of which 2302 have been confirmed as bona fide transiting planets (Borucki et al 2010(Borucki et al , 2011Batalha et al 2013;Burke et al 2014;Rowe et al 2015;Mullally et al 2015;Coughlin et al 2016;Thompson et al 2018). More than 70% of Kepler planets have radii 1 R ⊕ ≤ R p ≤ 4R ⊕ , such that super-Earths and mini-Neptunes make up a large fraction of the known exoplanet population 1 .…”

Section: Introductionmentioning

confidence: 99%

Formation of compact systems of super-Earths via dynamical instabilities and giant impacts

Poon

Nelson

Jacobson

et al. 2019

Monthly Notices of the Royal Astronomical Society

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NASA's Kepler mission discovered ∼ 700 planets in multi-planet systems containing 3 or more transiting bodies, many of which are super-Earths and mini-Neptunes in compact configurations. Using N-body simulations, we examine the in situ, final stage assembly of multi-planet systems via the collisional accretion of protoplanets. Our initial conditions are constructed using a subset of the Kepler 5-planet systems as templates. Two different prescriptions for treating planetary collisions are adopted. The simulations address numerous questions: do the results depend on the accretion prescription?; do the resulting systems resemble the Kepler systems, and do they reproduce the observed distribution of planetary multiplicities when synthetically observed?; do collisions lead to significant modification of protoplanet compositions, or to stripping of gaseous envelopes?; do the eccentricity distributions agree with those inferred for the Kepler planets? We find the accretion prescription is unimportant in determining the outcomes. The final planetary systems look broadly similar to the Kepler templates adopted, but the observed distributions of planetary multiplicities or eccentricities are not reproduced, because scattering does not excite the systems sufficiently. In addition, we find that ∼ 1% of our final systems contain a co-orbital planet pair in horseshoe or tadpole orbits. Post-processing the collision outcomes suggests they would not significantly change the ice fractions of initially ice-rich protoplanets, but significant stripping of gaseous envelopes appears likely. Hence, it may be difficult to reconcile the observation that many low mass Kepler planets have H/He envelopes with an in situ formation scenario that involves giant impacts after dispersal of the gas disc.

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“…Hydro-dynamical instabilities (HDI) are known to play a major role in shaping the morphology of the ISM, in particular in modifying the superficial structure of molecular clouds via Rayleigh-Taylor, Kelvin-Helmholtz, and self-gravity instabilities. All these processes can generate long and narrow streams of material (Hunter et al 1997;Coughlin & Nixon 2020). Among them, the Kelvin-Helmholtz instability (KHI) occurs at the interface of two fluids of different densities in relative shear motion and it is characterized by a wavelike periodic structure.…”

Section: Do the Iras 4a Fingers Trace Kelvin-helmholtz Instabilities?mentioning

confidence: 99%

A train of shocks at 3000 au scale? Exploring the clash of an expanding bubble into the NGC 1333 IRAS 4 region. SOLIS XIV

De Simone,

Codella,

Ceccarelli

et al. 2022

Preprint

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There is evidence that the star formation process is linked to the intricate net of filaments in molecular clouds, which may be also due to gas compression from external triggers. We studied the southern region of the Perseus NGC 1333 molecular cloud, known to be heavily shaped by similar external triggers, to shed light on the process that perturbed the filament where the Class 0 IRAS4 protostars lie. We use new IRAM-NOEMA observations of SiO and CH 3 OH, both known to trace violent events as shocks, toward IRAS 4A as part of the Large Program Seeds Of Life in Space (SOLIS). We detected three parallel elongated (>6000 au) structures, called fingers, with narrow line profiles (∼1.5 km s −1 ) peaked at the cloud systemic velocity, tracing gas with high density (5-20×10 5 cm −3 ) and high temperature (80-160 K). They are chemically different, with the northern finger traced by both SiO and CH 3 OH ([CH 3 OH]/[SiO]∼160-300), while the other two only by SiO ([CH 3 OH]/[SiO]≤ 40). Among various possibilities, a train of three shocks, distanced by ≥5000 yr, would be consistent with the observations if a substantial fraction of silicon, frozen onto the grain mantles, is released by the shocks. We suggest that the shock train is due to an expanding gas bubble, coming behind NGC 1333 from the southwest and clashing against the filament, where IRAS 4A lies. Finally, we propose a solution to the two-decades long debate on the nature and origin of the widespread narrow SiO emission observed in the south part of NGC 1333, namely that it is due to unresolved trains of shocks.

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The Gravitational Instability of Adiabatic Filaments

Cited by 26 publications

References 50 publications

Partial, zombie, and full tidal disruption of stars by supermassive black holes

Partial, zombie, and full tidal disruption of stars by supermassive black holes

Formation of compact systems of super-Earths via dynamical instabilities and giant impacts

A train of shocks at 3000 au scale? Exploring the clash of an expanding bubble into the NGC 1333 IRAS 4 region. SOLIS XIV

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