Global Hydromagnetic Simulations of Protoplanetary Disks with Stellar Irradiation and Simplified Thermochemistry

Gressel, Oliver; Ramsey, Jon P.; Brinch, Christian; Nelson, Richard P.; Turner, Neal J.; Bruderer, Simon

doi:10.48550/arxiv.2005.03431

Cited by 7 publications

(14 citation statements)

References 125 publications

(167 reference statements)

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“…Recent global non-ideal MHD simulations of magnetised disks, including more comprehensive disk microphysics and evolving both hemispheres, have confirmed these early results and shown that pronounced asymmetries between the lower and upper disk halves of the disk can develop and launch asymmetric outflows which persist over timescales of at least 1000 times the orbital period at the inner disk radius (Béthune et al 2017;Bai 2017;Gressel et al 2020;Riols et al 2020). However, most of these recent simulations do not currently include the very central regions of the disk (r ≤ 1 au) from which the high-velocity jets are launched.…”

Section: The Origin Of the Velocity Asymmetrymentioning

confidence: 80%

Launching the asymmetric bipolar jet of DO Tau

Erkal,

Dougados,

Coffey

et al. 2021

Preprint

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Context. The role of bipolar jets in the formation of stars, and in particular how they are launched, is still not well understood. Aims. We probe the protostellar jet launching mechanism, via high resolution observations of the near-IR [Fe ii]λ1.53,1.64 µm emission lines. Methods. We consider the case of the bipolar jet from Classical T Tauri star, DO Tau, and investigate the jet morphology and kinematics close to the star (within 140 au), using AO-assisted IFU observations from GEMINI/NIFS. Results. We find that the brighter, blue-shifted jet is collimated very quickly after it is launched. This early collimation requires the presence of magnetic fields. We confirm velocity asymmetries between the two lobes of the bipolar jet, and also confirm no time variability in the asymmetry over a 20 year interval. This sustained asymmetry is in accordance with recent simulations of magnetised disk-winds. We examine the data for signatures of jet rotation. We report an upper limit on differences in radial velocity of 6.3 and 8.7 km s −1 for the blue and red-shifted jets, respectively. Interpreting this as an upper limit on jet rotation implies that any steady, axisymmetric magneto-centrifugal model of jet launching is constrained to a launch radius in the disk-plane of r0 < 0.5 and 0.3 au for the blue and red-shifted jets, respectively. This supports an X-wind or narrow disk-wind model. However, the result pertains only to the observed high velocity [Fe ii] emission, and does not rule out a wider flow launched from a wider radius. We report detection of small amplitude jet axis wiggling in both lobes. We rule out orbital motion of the jet source as the cause. Precession can better account for the observations but requires double the precession angle, and a different phase for the counter-jet. Such non-solid body precession could arise from an inclined massive Jupiter companion, or a warping instability induced by launching a magnetic disk-wind. Conclusions. Overall, our observations are consistent with an origin of the DO Tau jets from the inner regions of the disk.

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Section: The Origin Of the Velocity Asymmetrymentioning

confidence: 80%

Launching the asymmetric bipolar jet of DO Tau

Erkal,

Dougados,

Coffey

et al. 2021

Preprint

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“…Expanding the set of molecular diagnostics for the inner winds, as well as the sample of disks with detections, to date restricted to suggestive evidence only in a handful of disks, will be important to better constrain wind mass loss rates. Disk wind models that properly couple thermodynamics and hydrodynamics are being developed (e.g., Gressel et al 2020) The sources CS Cha, MP Mus, T Cha, TY CrA, T CrA, V4046 Sgr, and VW Cha have very noisy or no published high-resolution optical spectra. For all of them except TY CrA, we retrieved from the ESO archive 9 the highest signalto-noise UVES spectra (R∼45,000) available 10 .…”

Section: Discussionmentioning

confidence: 99%

“…Interestingly, these nonideal MHD simulations persistently predict the presence of disk winds, defined as outflowing gas from a few scale heights above the disk midplane. The simulated winds extract enough angular momentum to drive accretion at the observed rates (e.g., Gressel et al 2015;Bai 2016;Gressel et al 2020). These outer winds (beyond a few au out to tens of au in some models), combined with the closer-in winds likely responsible for outflowing gas at hundreds of km/s (hereafter jets, e.g., Frank et al 2014), could drive disk evolution with important implications for planet formation and migration (e.g., Ogihara et al 2018;Kimmig et al 2020).…”

Section: Introductionmentioning

confidence: 91%

The Evolution of Disk Winds from a Combined Study of Optical and Infrared Forbidden Lines

Pascucci,

Banzatti,

Gorti

et al. 2020

Preprint

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We analyze high-resolution (∆v ≤ 10 km/s) optical and infrared spectra covering the [O I] 6300 Å and [Ne II] 12.81 µm lines from a sample of 31 disks in different evolutionary stages. Following work at optical wavelengths, we use Gaussian profiles to fit the [Ne II] lines and classify them into HVC (LVC) if the line centroid is more (less) blueshifted than 30 km/s with respect to the stellar radial velocity. Unlike for the [O I] where a HVC is often accompanied by a LVC, all 17 sources with a [Ne II] detection have either a HVC or a LVC. [Ne II] HVCs are preferentially detected toward high accretors ( Ṁacc > 10 −8 M /yr) while LVCs are found in sources with low Ṁacc , low [O I] luminosity, and large infrared spectral index (n 13−31 ). Interestingly, the [Ne II] and [O I] LVC luminosities display an opposite behaviour with n 13−31 : as the inner dust disk depletes (higher n 13−31 ) the [Ne II] luminosity increases while the [O I] weakens. The [Ne II] and [O I] HVC profiles are generally similar with centroids and FWHMs showing the expected behaviour from shocked gas in micro-jets. In contrast, the [Ne II] LVC profiles are typically more blueshifted and narrower than the [O I] profiles. The FWHM and centroid vs. disk inclination suggest that the [Ne II]LVC predominantly traces unbound gas from a slow, wideangle wind that has not lost completely the Keplerian signature from its launching region. We sketch an evolutionary scenario that could explain the combined [O I] and [Ne II] results and includes screening of hard (∼ 1 keV) X-rays in inner, mostly molecular, MHD winds.

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“…The FLD method is well-suited for radiation transport in optically-thick media but is not adapted to strongly anisotropic radiation fields. The particular treatment of the stellar radiation, also called irradiation, has been improved later on to track the higher-energy stellar photons and compute accurately the opacity during their first interaction with the ambient medium (Kuiper et al 2010b, Flock et al 2013, Ramsey & Dullemond 2015, Rosen et al 2017, Mignon-Risse et al 2020,Gressel et al 2020, Fuksman et al 2020.…”

Section: Introductionmentioning

confidence: 99%

Collapse of turbulent massive cores with ambipolar diffusion and hybrid radiative transfer I. Accretion and multiplicity

Mignon-Risse,

González,

Commerçon

et al. 2021

Preprint

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Context. Massive stars form in magnetized and turbulent environments, and are often located in stellar clusters. The accretion and outflows mechanisms associated to forming massive stars, as well as the origin of their system's stellar multiplicity are poorly understood.Aims. We study the influence of both magnetic fields and turbulence on the accretion mechanism of massive protostars and their multiplicity. We also focus on disk formation as a pre-requisite for outflow launching. Methods. We present a series of four radiation-magnetohydrodynamical simulations of the collapse of a massive magnetized, turbulent core of 100 M with the adaptive-mesh-refinement code Ramses, including a hybrid radiative transfer method for stellar irradiation and ambipolar diffusion. We vary the Mach and Alfvénic Mach numbers to probe sub-and superalfvénic turbulence as well as suband supersonic turbulence regimes. Results. Subalfvénic turbulence leads to single stellar systems while superalfvénic turbulence leads to binary formation from disk fragmentation following spiral arm collision, with mass ratios of 1.1 − 1.6 and a separation of several hundreds AU increasing with the initial turbulent support and with time. In those runs, infalling gas reaches the individual disks via a transient circumbinary structure. Magnetically-regulated, thermally-dominated (plasma beta β > 1), Keplerian disks form in all runs, with sizes 100 − 200 AU and masses 1 − 8 M . The disks around primary and secondary sink particles share similar properties. We obtain mass accretion rates of ∼10 −4 M yr −1 onto the protostars and observe higher accretion rates onto the secondary stars than onto their primary star companion. The primary disk orientation is found to be set by the initial angular momentum carried by turbulence rather than by magnetic fields. Even without turbulence, axisymmetry and north-south symmetry with respect to the disk plane are broken by the interchange instability and the presence of thermally-dominated streamers, respectively. Conclusions. Small ( 300 AU) massive protostellar disks as those frequently observed nowadays can only be reproduced so far in the presence of (moderate) magnetic fields with ambipolar diffusion, even in a turbulent medium. The interplay between magnetic fields and turbulence sets the multiplicity of stellar clusters. A plasma beta β > 1 is a good indicator to distinguish streamers and individual disks from their surroundings.

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Global Hydromagnetic Simulations of Protoplanetary Disks with Stellar Irradiation and Simplified Thermochemistry

Cited by 7 publications

References 125 publications

Launching the asymmetric bipolar jet of DO Tau

Launching the asymmetric bipolar jet of DO Tau

The Evolution of Disk Winds from a Combined Study of Optical and Infrared Forbidden Lines

Collapse of turbulent massive cores with ambipolar diffusion and hybrid radiative transfer I. Accretion and multiplicity

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