The 3D Structure of CO Depletion in High-mass Prestellar Regions

Bovino, S.; Ferrada-Chamorro, Simón; Lupi, Alessandro; Sabatini, Giovanni; Giannetti, A.; Schleicher, Dominik R. G.

doi:10.3847/1538-4357/ab53e4

Cited by 31 publications

(48 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the future, such comparative analysis will be applied to the entire sample. More comprehensive chemical modeling taking into account the spin states of H 2 and other relevant species (Hugo et al 2009;Sipilä et al 2010;Kong et al 2015;Bovino et al 2017) and coupling with dynamical evolution (e.g., Goodson et al 2016;Bovino et al 2019) are needed, to understand the feedback of protostellar heating on the depletion efficiency, and therefore to profile the entire evolutionary processes of these sources.…”

Section: Dynamical and Chemical Timescalesmentioning

confidence: 99%

The Chemical Structure of Young High-mass Star-forming Clumps. I. Deuteration

Feng¹,

Caselli

Wang³

et al. 2019

ApJ

View full text Add to dashboard Cite

The chemical structure of high-mass star nurseries is important for a general understanding of star formation. Deuteration is a key chemical process in the earliest stages of star formation because its efficiency is sensitive to the environment. Using the IRAM-30 m telescope at 1.3-4.3 mm wavelengths, we have imaged two parsecscale high-mass protostellar clumps (P1 and S) that show different evolutionary stages but are located in the same giant filamentary infrared dark cloud G28.34+0.06. Deep spectral images at subparsec resolution reveal the dust and gas physical structures of both clumps. We find that (1) the low-J lines of N 2 H + , HCN, HNC, and HCO + isotopologues are subthermally excited; and (2) the deuteration of N 2 H + is more efficient than that of HCO + , HCN, and HNC by an order of magnitude. The deuterations of these species are enriched toward the chemically younger clump S compared with P1, indicating that this process favors the colder and denser environment (T kin ∼ 14K, N(NH 3 ) ∼ 9 × 10 15 cm −2 ). In contrast, single deuteration of NH 3 is insensitive to the environmental difference between P1 and S; and (3) single deuteration of CH 3 OH (> 10%) is detected toward the location where CO shows a depletion of ∼ 10. This comparative chemical study between P1 and S links the chemical variations to the environmental differences and shows chemical similarities between the early phases of high-and low-mass star-forming regions.

show abstract

Section: Dynamical and Chemical Timescalesmentioning

confidence: 99%

The Chemical Structure of Young High-mass Star-forming Clumps. I. Deuteration

Feng¹,

Caselli

Wang³

et al. 2019

ApJ

View full text Add to dashboard Cite

show abstract

“…If there is a spatial structure of CO, this could influence the final result of our simulation. In Bovino et al (2019), they discuss the CO depletion structure of their simulated high-mass pre-stellar region. Their result shows that the CO depletion does have a spatial structure and thus influences the structure of deuterium fractionation also.…”

Section: Discussionmentioning

confidence: 99%

“…Furthermore, the increasing size of the chemical reaction network limits the simulation efficiency. In a recent work, Bovino et al (2019) also applied KROME to investigate deuterium fractionation on multiple scales of clumps and cores. They considered heavy elements, like C, N, and O and focused on discussing the influence of time-dependent depletion/desorption reactions to CO depletion structures inside the clumps and cores.…”

Section: Introductionmentioning

confidence: 99%

Deuterium chemodynamics of massive pre-stellar cores

Hsu

Tan

Goodson

et al. 2021

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

High levels of deuterium fractionation of N2H+ (i.e. $\mathrm{D^{{\mathrm{N_2H^+}}}_{\text{frac}}}$≳ 0.1) are often observed in pre-stellar cores (PSCs) and detection of N2D+ is a promising method to identify elusive massive PSCs. However, the physical and chemical conditions required to reach such high levels of deuteration are still uncertain, as is the diagnostic utility of N2H+ and N2D+ observations of PSCs. We perform 3D magnetohydrodynamics simulations of a massive, turbulent, magnetized PSC, coupled with a sophisticated deuteration astrochemical network. Although the core has some magnetic/turbulent support, it collapses under gravity in about one free-fall time, which marks the end of the simulations. Our fiducial model achieves relatively low $\mathrm{D^{{\mathrm{N_2H^+}}}_{\text{frac}}}$∼0.002 during this time. We then investigate effects of initial ortho-para ratio of H2 ($\mathrm{OPR^{H_2}}$), temperature, cosmic ray (CR) ionization rate, CO and N-species depletion factors, and prior PSC chemical evolution. We find that high CR ionization rates and high depletion factors allow the simulated $\mathrm{D^{{\mathrm{N_2H^+}}}_{\text{frac}}}$ and absolute abundances to match observational values within one free-fall time. For $\mathrm{OPR^{H_2}}$, while a lower initial value helps the growth of $\mathrm{D^{{\mathrm{N_2H^+}}}_{\text{frac}}}$, the spatial structure of deuteration is too widespread compared to observed systems. For an example model with elevated CR ionization rates and significant heavy element depletion, we then study the kinematic and dynamic properties of the core as traced by its N2D+ emission. The core, undergoing quite rapid collapse, exhibits disturbed kinematics in its average velocity map. Still, because of magnetic support, the core often appears kinematically subvirial based on its N2D+ velocity dispersion.

show abstract

“…The chemical network we employed is based on Grassi et al (2017), which is an updated version of that in Glover et al (2010). We included isomer-dependent chemistry, by employing the most up-to-date reaction rates (Sipilä et al 2015;Bovino et al 2019). The final network includes 40 species: H, H + , He, He + , He ++ , ortho-H 2 , para-H 2 , ortho-…”

Section: Microphysicsmentioning

confidence: 99%

“…Federrath et al 2010aFederrath et al , 2016Padoan & Nordlund 2011;Padoan et al 2016), or on the small scales typical of these substructures, neglecting the large-scale environment and focussing on the last stages of the gravitational collapse (e.g. Bovino et al 2019Bovino et al , 2020. Unfortunately, while small-scale simulations are extremely useful for studying the final stages of the gravitational collapse and comparing the results with observations of protostellar cores, the detailed chemical conditions at the onset of gravitational collapse are still very uncertain, and can be constrained only via self-consistent studies on MC scales.…”

Section: Introductionmentioning

confidence: 99%

On the low ortho-to-para H₂ ratio in star-forming filaments

Lupi

Bovino

2021

A&A

Self Cite

View full text Add to dashboard Cite

The formation of stars and planetary systems is a complex phenomenon that relies on the interplay of multiple physical processes. Nonetheless, it represents a crucial stage for our understanding of the Universe, and in particular of the conditions leading to the formation of key molecules (e.g. water) on comets and planets. Herschel observations demonstrated that stars form in gaseous filamentary structures in which the main constituent is molecular hydrogen (H2). Depending on its nuclear spin H2 can be found in two forms: ‘ortho’ with parallel spins and ‘para’ where the spins are anti-parallel. The relative ratio among these isomers, the ortho-to-para ratio (OPR), plays a crucial role in a variety of processes related to the thermodynamics of star-forming gas and to the fundamental chemistry affecting the deuteration of water in molecular clouds, commonly used to determine the origin of water in Solar System bodies. Here, for the first time, we assess the evolution of the OPR starting from the warm neutral medium by means of state-of-the-art 3D magnetohydrodynamic simulations of turbulent molecular clouds. Our results show that star-forming clouds exhibit a low OPR (≪0.1) already at moderate densities (∼1000 cm−3). We also constrain the cosmic-ray ionisation rate, finding that 10−16 s−1 is the lower limit required to explain the observations of diffuse clouds. Our results represent a step forward in the understanding of the star and planet formation processes providing a robust determination of the chemical initial conditions for both theoretical and observational studies.

show abstract

The 3D Structure of CO Depletion in High-mass Prestellar Regions

Cited by 31 publications

References 47 publications

The Chemical Structure of Young High-mass Star-forming Clumps. I. Deuteration

The Chemical Structure of Young High-mass Star-forming Clumps. I. Deuteration

Deuterium chemodynamics of massive pre-stellar cores

On the low ortho-to-para H₂ ratio in star-forming filaments

Contact Info

Product

Resources

About

The 3D Structure of CO Depletion in High-mass Prestellar Regions

Cited by 31 publications

References 47 publications

The Chemical Structure of Young High-mass Star-forming Clumps. I. Deuteration

The Chemical Structure of Young High-mass Star-forming Clumps. I. Deuteration

Deuterium chemodynamics of massive pre-stellar cores

On the low ortho-to-para H2 ratio in star-forming filaments

Contact Info

Product

Resources

About

On the low ortho-to-para H₂ ratio in star-forming filaments