Photoevaporation of disks around massive stars and application to ultracompact H II regions

Hollenbach, D. J.; Johnstone, Doug; Lizano, Susana; Shu, Frank H.

doi:10.1086/174276

Cited by 579 publications

(780 citation statements)

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“…Photoevaporation in disks tends to produce winds at radii larger than the critical radius, where the photoionized material has sufficient velocity to escape. For ionization by EUV photons, this tends to occur at radii of 5 au (e.g., Hollenbach et al 1994;Gorti & Hollenbach 2009), corresponding to dynamical timescales of a few years. Nonuniformities in the disk are, therefore, likely to cause longerterm variability in the free-free emission.…”

Section: Variabilitymentioning

confidence: 99%

A Vla Survey for Faint Compact Radio Sources in the Orion Nebula Cluster

Sheehan

Eisner

Mann

et al. 2016

ApJ

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We present Karl G. Jansky Very Large Array 1.3, 3.6, and 6 cm continuum maps of compact radio sources in the Orion Nebular Cluster (ONC). We mosaicked 34 arcmin 2 at 1.3 cm, 70 arcmin 2 at 3.6 cm and 109 arcmin 2 at 6 cm, containing 778 near-infrared detected young stellar objects and 190 Hubble Space Telescope-identified proplyds (with significant overlap between those characterizations). We detected radio emission from 175 compact radio sources in the ONC, including 26 sources that were detected for the first time at these wavelengths. For each detected source, we fitted a simple free-free and dust emission model to characterize the radio emission. We extrapolate the free-free emission spectrum model for each source to ALMA bands to illustrate how these measurements could be used to correctly measure protoplanetary disk dust masses from submillimeter flux measurements. Finally, we compare the fluxes measured in this survey with previously measured fluxes for our targets, as well as four separate epochs of 1.3 cm data, to search for and quantify the variability of our sources.

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Section: Variabilitymentioning

confidence: 99%

A Vla Survey for Faint Compact Radio Sources in the Orion Nebula Cluster

Sheehan

Eisner

Mann

et al. 2016

ApJ

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“…The disk begins to evaporate due to photo-ionization heating once it spreads to radii approaching the so-called gravitational radius (Hollenbach et al 1994;Adams et al 2004),…”

Section: Photo-evaporation Phasementioning

confidence: 99%

Merger of a white dwarf–neutron star binary to 10²⁹carat diamonds: origin of the pulsar planets

Margalit

Metzger

2016

Mon. Not. R. Astron. Soc.

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We show that the merger and tidal disruption of a C/O white dwarf (WD) by a neutron star (NS) binary companion provides a natural formation scenario for the PSR B1257+12 planetary system. Starting with initial conditions for the debris disk produced of the disrupted WD, we model its long term viscous evolution, including for the first time the effects of mass and angular momentum loss during the early radiatively inefficient accretion flow (RIAF) phase and accounting for the unusual C/O composition on the disk opacity. For plausible values of the disk viscosity α ∼ 10 −3 − 10 −2 and the RIAF mass loss efficiency, we find that the disk mass remaining near the planet formation radius at the time of solid condensation is sufficient to explain the pulsar planets. Rapid rocky planet formation via gravitational instability of the solid carbon-dominated disk is facilitated by the suppression of vertical shear instabilities due to the high solid-to-gas ratio. Additional evidence supporting a WD-NS merger scenario includes (1) the low observed occurrence rate of pulsar planets ( 1% of NS birth), comparable to the expected WD-NS merger rate; (2) accretion by the NS during the RIAF phase is sufficient to spin PSR B1257+12 up to its observed 6 ms period; (3) similar models of 'low angular momentum' disks, such as those produced from supernova fallback, find insufficient mass reaching the planet formation radius. The unusually high space velocity of PSR B1257+12 of 326 km s −1 suggests a possible connection to the Calcium-rich transients, dim supernovae which occur in the outskirts of their host galaxies and were proposed to result from mergers of WD-NS binaries receiving SN kicks. The C/O disk composition implied by our model likely results in carbon-rich planets with diamond interiors.

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“…The EUV photoevaporation model of disks was first and extensively developed by Hollenbach et al (1994). Because a typical disk is optically thick to Ly continuum radiation, it is rather the diffuse recombination radiation field that ionizes the disk gas at large radii.…”

Section: Epj Web Of Conferencesmentioning

confidence: 99%

“…Because a typical disk is optically thick to Ly continuum radiation, it is rather the diffuse recombination radiation field that ionizes the disk gas at large radii. From such models, Hollenbach et al (1994) …”

Section: Epj Web Of Conferencesmentioning

confidence: 99%

Ionization and heating by X-rays and cosmic rays

Güdel

2015

EPJ Web of Conferences

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Abstract. High-energy radiation from the central T Tauri and protostars plays an important role in shaping protoplanetary disks and influences their evolution. Such radiation, in particular X-rays and extreme-ultraviolet (EUV) radiation, is predominantly generated in unstable stellar magnetic fields (e.g., the stellar corona), but also in accretion hot spots. Even jets may produce X-ray emission. Cosmic rays, i.e., high-energy particles either from the interstellar space or from the star itself, are of crucial importance. Both highenergy photons and particles ionize disk gas and lead to heating. Ionization and heating subsequently drive chemical networks, and the products of these processes are accessible through observations of molecular line emission. Furthermore, ionization supports the magnetorotational instability and therefore drives disk accretion, while heating of the disk surface layers induces photoevaporative flows. Both processes are crucial for the dispersal of protoplanetary disks and therefore critical for the time scales of planet formation. This chapter introduces the basic physics of ionization and heating starting from a quantum mechanical viewpoint, then discusses relevant processes in astrophysical gases and their applications to protoplanetary disks, and finally summarizes some properties of the most important high-energy sources for protoplanetary disks.

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Photoevaporation of disks around massive stars and application to ultracompact H II regions

Cited by 579 publications

References 0 publications

A Vla Survey for Faint Compact Radio Sources in the Orion Nebula Cluster

A Vla Survey for Faint Compact Radio Sources in the Orion Nebula Cluster

Merger of a white dwarf–neutron star binary to 10²⁹carat diamonds: origin of the pulsar planets

Ionization and heating by X-rays and cosmic rays

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Photoevaporation of disks around massive stars and application to ultracompact H II regions

Cited by 579 publications

References 0 publications

A Vla Survey for Faint Compact Radio Sources in the Orion Nebula Cluster

A Vla Survey for Faint Compact Radio Sources in the Orion Nebula Cluster

Merger of a white dwarf–neutron star binary to 1029carat diamonds: origin of the pulsar planets

Ionization and heating by X-rays and cosmic rays

Contact Info

Product

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Merger of a white dwarf–neutron star binary to 10²⁹carat diamonds: origin of the pulsar planets