The birth environment of planetary systems

Parker, R. J.

doi:10.1098/rsos.201271

Cited by 48 publications

(36 citation statements)

References 241 publications

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“…Note that if these regions had similar initial volume averaged densities (equation 15), then the radii of the highly substructured (D = 1.6) simulations would be smaller, and in that case the more substructured regions would likely lead to more disc destruction than in the smoother regions. However, it is the local density the more accurately traces the dynamical evolution of these star-forming regions (Parker 2020), despite this not being commonly adopted by observers or simulators to characterize the density of star-forming regions. Interestingly, the simulations with no initial substructure, shown in panel (h), display a flattening of the disc fractions after ∼0.5 Myr, before decreasing again.…”

Section: Initial Spatial Structurementioning

confidence: 99%

Far and extreme ultraviolet radiation fields and consequent disc destruction in star-forming regions

Parker

Nicholson

Alcock

2021

Monthly Notices of the Royal Astronomical Society

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The first stages of planet formation usually occur when the host star is still in a (relatively) dense star-forming region, where the effects of the external environment may be important for understanding the outcome of the planet formation process. In particular, star-forming regions that contain massive stars have strong far-ultraviolet (FUV) and extreme ultraviolet (EUV) radiation fields, which can induce mass-loss from protoplanetary discs due to photoevaporation. In this paper, we present a parameter-space study of the expected FUV and EUV fields in N-body simulations of star-forming regions with a range of initial conditions. We then use recently published models to determine the mass-loss due to photoevaporation from protoplanetary discs. In particular, we focus on the effects of changing the initial degree of spatial structure and initial virial ratio in the star-forming regions, as well as the initial stellar density. We find that the FUV fields in star-forming regions are much higher than in the interstellar medium, even when the regions have stellar densities as low as in the Galactic field, due to the presence of intermediate-mass, and massive, stars (>5 M⊙). These strong radiation fields lead to the destruction of the gas component in protoplanetary discs within 1 Myr, implying that gas giant planets must either form extremely rapidly (<1 Myr), or that they exclusively form in star-forming regions like Taurus, which contain no intermediate-mass or massive stars. The latter scenario is in direct tension with meteoritic evidence from the Solar system that suggests the Sun and its protoplanetary disc was born in close proximity to massive stars.

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Section: Initial Spatial Structurementioning

confidence: 99%

Far and extreme ultraviolet radiation fields and consequent disc destruction in star-forming regions

Parker

Nicholson

Alcock

2021

Monthly Notices of the Royal Astronomical Society

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“…For example, the gas giant planet population might be enhanced compared to this study. (iv) Close flybys can lead to gravitational instabilities that might eventually trigger planet formation (Thies et al 2010;Parker 2020). Although the most acceptable pathway of planet formation is thought to be the core accretion scenario (e.g, Wetherill 1980;Kokubo & Ida 1998;Thommes et al 2003;Coleman & Nelson 2014), planets could also form from the fragmentation of thermodynamically cold circumstellar discs (Kuiper 1951;Cameron 1978;Boss 1997;Gammie 2001;Rice et al 2003;Tanga et al 2004;Rafikov 2005;Durisen et al 2007;Mayer et al 2002).…”

Section: Discussionmentioning

confidence: 99%

“…Disc truncation in stellar clusters happens when flybys occur in star forming region with high initial stellar densities, for example in the Orion Nebula Cluster (ONC), NGC 6611 and NGC 2264 (Breslau et al 2014;Parker 2020;Parker & Schoettler 2022). Observation of star formation regions show that the properties of discs-particularly their radii, tend to be smaller-in the most dense star-forming regions compared to lower density regions (de Juan Ovelar et al 2012;Ansdell et al 2017;Eisner et al 2018;Winter et al 2018).…”

Section: Introductionmentioning

confidence: 99%

Planet population synthesis: The role of stellar encounters

Ndugu,

Abedigamba,

Andama

2022

Preprint

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Depending on the stellar densities, protoplanetary discs in stellar clusters undergo: background heating; disc truncation-driven by stellar encounter; and photo-evaporation. Disc truncation leads to reduced characteristic sizes and disc masses that eventually halts gas giant planet formation. We investigate how disc truncation impacts planet formation via pebble-based core accretion paradigm, where pebble sizes were derived from the full grain-size distribution within the disc lifetimes. We make the bestcase assumption of one embryo and one stellar encounter per disc. Using planet population syntheses techniques, we find that disc truncation shifts the disc mass distributions to the lower margins. This consequently lowered the gas giant occurrence rates. Despite the reduced gas giant formation rates in clustered discs, the encounter models mostly show as in the isolated field; the cold Jupiters are more frequent than the hot Jupiters, consistent with observation. Moreover, the ratio of hot to cold Jupiters depend on the periastron distribution of the perturbers with linear distribution in periastron ratio showing enhanced hot to cold Jupiters ratio in comparison to the remaining models. Our results are valid in the best-case scenario corresponding to our assumptions of: only one disc encounter with a perturber, ambient background heating and less rampant photo-evaporation. It is not known exactly of how much gas giant planet formation would be affected should disc encounter, background heating and photo-evaporation act in a concert. Thus, our study will hopefully serve as motivation for quantitative investigations of the detailed impact of stellar cluster environments on planet formations.

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“…The compositional mixture for the initial stages of rocky planets is set by the snowlines of key volatile species 4 and this has been linked to the question of the origin of Earth's own water 5,6 . A reverse picture is seen for gas-giants whose atmospheres reflect the gas composition within their birth zone 7 . Figure 1 depicts the drastic change of the elemental C/O and N/O abundance ratios in the gas and solids due to the ice-to-gas transition of the major carrier of these elements as the mass accretes towards the central star.…”

Section: Introductionmentioning

confidence: 99%

Thermal desorption of interstellar ices. A review on the controlling parameters and their implications fromsnowlines to chemical complexity

Minissale¹,

Aikawa²,

Bergin³

et al. 2022

Preprint

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The evolution of star-forming regions and their thermal balance are strongly influenced by their chemical composition, that, in turn, is determined by the physicochemical processes that govern the transition between the gas phase and the solid state, specifically icy dust grains (e.g., particles adsorption and desorption). Gas-grain and grain-gas transitions as well as formation and sublimation of interstellar ices are thus essential elements of understanding astrophysical observations of cold environments (e.g., pre-stellar cores) where unexpected amounts of a large variety of chemical species have been observed in the gas phase. Adsorbed atoms and molecules also undergo chemical reactions which are not efficient in the gas phase. Therefore the parameterization of the physical properties of atoms and molecules interacting with dust grain particles is clearly a key aspect to interpret astronomical observations and to build realistic and predictive astrochemical models. In this consensus evaluation, we focus on parameters controlling the thermal desorption of ices and how these determine pathways towards molecular complexity and define the location of snowlines, which ultimately influence the planet formation process.We review different crucial aspects of desorption parameters both from a theoretical and experimental point of view. We critically assess the desorption parameters (the binding energies E b and the pre-exponential factor ν) commonly used in the astrochemical community for astrophysically relevant species and provide tables with recommended values. The aim of these tables is to provide a coherent set of critically assessed desorption parameters for common use in future work. In addition, we show that a non-trivial determination of the pre-exponential factor ν using the Transition State Theory can affect the binding energy value. The primary focus is on pure ices, but we also discuss the desorption behavior of mixed, i.e. astronomically more realistic ices. This allows discussion of segregation effects. Finally, we conclude this work by discussing the limitations of theoretical and experimental approaches currently used to determine the desorption properties with suggestions for future improvements.

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The birth environment of planetary systems

Cited by 48 publications

References 241 publications

Far and extreme ultraviolet radiation fields and consequent disc destruction in star-forming regions

Far and extreme ultraviolet radiation fields and consequent disc destruction in star-forming regions

Planet population synthesis: The role of stellar encounters

Thermal desorption of interstellar ices. A review on the controlling parameters and their implications fromsnowlines to chemical complexity

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