Disk Dispersal: Theoretical Understanding and Observational Constraints

Gorti, Uma; Liseau, R.; Sándor, Zs.; Clarke, C. J.

doi:10.1007/978-94-024-1518-6_6

Cited by 2 publications

(3 citation statements)

References 153 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The main part is supposed to have been accreted onto the central star or physically removed from the disk and one proposed mechanism is photoevaporation (see recent reviews in e.g. Alexander et al 2014; Gorti et al 2015). Indeed, disks are subject to highly energetic photons that can sufficiently heat the gas at the disk surface to make it overcomes the gravitational field leading to escape flows and mass-loss.…”

Section: Introductionmentioning

confidence: 99%

Herschel survey and modelling of externally-illuminated photoevaporating protoplanetary disks

Champion

Berné

Vicente

et al. 2017

A&A

View full text Add to dashboard Cite

Context. Protoplanetary disks undergo substantial mass-loss by photoevaporation, a mechanism that is crucial to their dynamical evolution. However, the processes regulating the gas energetics have not so far been well constrained by observations. Aims. We aim to study the processes involved in disk photoevaporation when it is driven by far-UV photons (i.e. 6 < E < 13.6 eV). Methods. We present a unique Herschel survey and new ALMA observations of four externally-illuminated photoevaporating disks (a.k.a. proplyds). To analyse these data, we developed a 1D model of the photodissociation region (PDR) of a proplyd, based on the Meudon PDR code. Using this model, we computed the far infrared line emission.Results. With this model, we successfully reproduce most of the observations and derive key physical parameters, that is, the densities at the disk surface of about 10 6 cm −3 and local gas temperatures of about 1000 K. Our modelling suggests that all studied disks are found in a transitional regime resulting from the interplay between several heating and cooling processes that we identify. These differ from those dominating in classical PDRs, meaning the grain photo-electric effect and cooling by OI and CII FIR lines. This specific energetic regime is associated to an equilibrium dynamical point of the photoevaporation flow: the mass-loss rate is self-regulated to keep the envelope column density at a value that maintains the temperature at the disk surface around 1000 K. From the physical parameters derived from our best-fit models, we estimate mass-loss rates -of the order of 10 −7 M /yr -that are in agreement with earlier spectroscopic observation of ionised gas tracers. This holds only if we assume photoevaporation in the supercritical regime where the evaporation flow is launched from the disk surface at sound speed. Conclusions. We have identified the energetic regime regulating FUV-photoevaporation in proplyds. This regime could be implemented into models of the dynamical evolution of protoplanetary disks.

show abstract

Section: Introductionmentioning

confidence: 99%

Herschel survey and modelling of externally-illuminated photoevaporating protoplanetary disks

Champion

Berné

Vicente

et al. 2017

A&A

View full text Add to dashboard Cite

show abstract

“…In these regions, the far ultraviolet (FUV) and extreme ultraviolet (EUV) radiation from the most massive stars can curtail disk lifetimes of the low-mass protostars via external photo-evaporation, caused by the heating and dissociating effects of ionizing radiation (e.g. Johnstone et al 1998;Adams et al 2004;Clarke 2007;Gorti et al 2015). Depending on the intensity and the duration of the exposure, photo-evaporation by external irradiation can potentially lead to disk dispersal on timescales shorter than the minimum 1 − 2 Myr required for planet formation (Hubickyj et al 2005;Lissauer et al 2009;Najita & Kenyon 2014;ALMA Partnership et al 2015).…”

Section: Introductionmentioning

confidence: 99%

“…Although internal photo-evaporation due to FUV and x-ray radiation from the protostar itself may be important, this effect generally acts on longer timescales of about 3 − 5 Myr (e.g. Owen et al 2012;Gorti et al 2015). Understanding the impact of external photo-evaporation on disks within massive clusters is key to assessing their chances for survival and their planet-formation capacity.…”

Section: Introductionmentioning

confidence: 99%

Protoplanetary disks in the hostile environment of Carina

Mesa-Delgado,

Zapata,

Henney

et al. 2016

Preprint

View full text Add to dashboard Cite

We report the first direct imaging of protoplanetary disks in the star-forming region of Carina, the most distant, massive cluster in which disks have been imaged. Using the Atacama Large Millimeter/sub-millimeter Array (ALMA), disks are observed around two young stellar objects (YSOs) that are embedded inside evaporating gaseous globules and exhibit jet activity. The disks have an average size of 120 AU and total masses of 30 and 50 M Jup . Given the measured masses, the minimum timescale required for planet formation (∼ 1 − 2 Myr) and the average age of the Carina population (∼ 1 − 4 Myr), it is plausible that young planets are present or their formation is currently ongoing in these disks. The non-detection of millimeter emission above the 4σ threshold (∼ 7M Jup ) in the core of the massive cluster Trumpler 14, an area containing previously identified proplyd candidates, suggest evidence for rapid photo-evaporative disk destruction in the cluster's harsh radiation field. This would prevent the formation of giant gas planets in disks located in the cores of Carina's dense sub-clusters, whereas the majority of YSO disks in the wider Carina region remain unaffected by external photo-evaporation.

show abstract

Disk Dispersal: Theoretical Understanding and Observational Constraints

Cited by 2 publications

References 153 publications

Herschel survey and modelling of externally-illuminated photoevaporating protoplanetary disks

Herschel survey and modelling of externally-illuminated photoevaporating protoplanetary disks

Protoplanetary disks in the hostile environment of Carina

Contact Info

Product

Resources

About