Chemistry of Protoplanetary Disks

Markwickan, A.J.; Charnley, S. B.

doi:10.1007/1-4020-2305-7_3

Cited by 13 publications

(14 citation statements)

References 129 publications

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“…The dynamic environment of the solar nebula with the simultaneous presence of gas, particles, and energeticprocesses,includingshockwaves,lightning, and radiation can trigger a rich organic chemistry leading to organic molecules (Chick andCassen 1997, Gorti et al 2009). Turbulent motion led to radial mixing of the products within the disk (Markwick and Charnley 2004;Visser et al 2007;Dullemond et al 2008).…”

Section: Solar System Formationmentioning

confidence: 99%

Cosmic Carbon Chemistry: From the Interstellar Medium to the Early Earth

Ehrenfreund¹,

Cami²

2010

Cold Spring Harbor Perspectives in Biology

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Astronomical observations have shown that carbonaceous compounds in the gas and solid state, refractory and icy are ubiquitous in our and distant galaxies. Interstellar molecular clouds and circumstellar envelopes are factories of complex molecular synthesis. A surprisingly large number of molecules that are used in contemporary biochemistry on Earth are found in the interstellar medium, planetary atmospheres and surfaces, comets, asteroids and meteorites, and interplanetary dust particles. In this article we review the current knowledge of abundant organic material in different space environments and investigate the connection between presolar and solar system material, based on observations of interstellar dust and gas, cometary volatiles, simulation experiments, and the analysis of extraterrestrial matter. Current challenges in astrochemistry are discussed and future research directions are proposed.

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Section: Solar System Formationmentioning

confidence: 99%

Cosmic Carbon Chemistry: From the Interstellar Medium to the Early Earth

Ehrenfreund¹,

Cami²

2010

Cold Spring Harbor Perspectives in Biology

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“…The chemical composition of the gas in the inner regions of circumstellar disks plays an important role in determining the eventual composition of the comets and atmospheres of any planets that may form from that gas (see reviews by Prinn 1993;Ehrenfreund & Charnley 2000;Markwick & Charnley 2004;Bergin 2011). In the last few years, observations with the Spitzer Space Telescope have revealed a rich chemistry in the inner few astronomical units (AU) of disks around low-mass stars, containing high abundances of HCN, C 2 H 2 , CO 2 , H 2 O and OH (Lahuis et al 2006a;Salyk et al 2008Salyk et al , 2011aPascucci et al 2009;Kruger et al 2011;Najita et al 2010;Pontoppidan et al 2010).…”

Section: Introductionmentioning

confidence: 99%

Exploring organic chemistry in planet-forming zones

Bast

Lahuis

Dishoeck

et al. 2013

A&A

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Context. Over the last few years, the chemistry of molecules other than CO in the planet-forming zones of disks is starting to be explored with Spitzer and high-resolution ground-based data. However, these studies have focused only on a few simple molecules. Aims. The aim of this study is to put observational constraints on the presence of more complex organic and sulfur-bearing molecules predicted to be abundant in chemical models of disks and to simulate high resolution spectra in view of future missions. Methods. High signal-to-noise ratio (S/N) Spitzer spectra of the near edge-on disks IRS 46 and GV Tau are used to search for midinfrared absorption bands of various molecules. These disks are good laboratories because absorption studies do not suffer from low line/continuum ratios that plague emission data. Simple local thermodynamic equilibrium (LTE) slab models are used to infer column densities (or upper limits) and excitation temperatures. Results. Mid-infrared bands of HCN, C 2 H 2 and CO 2 are clearly detected toward both sources. The HCN and C 2 H 2 absorption arises in warm gas with excitation temperatures of 400−700 K, whereas the CO 2 absorption originates in cooler gas of ∼250 K. Column densities and their ratios are comparable for the two sources. No other absorption features are detected at the 3σ level. Column density limits of the majority of molecules predicted to be abundant in the inner disk -C 2 H 4 , C 2 H 6 , C 6 H 6 , C 3 H 4 , C 4 H 2 , CH 3 , HNC, HC 3 N, CH 3 CN, NH 3 and SO 2 -are determined and compared with disk models. Conclusions. The inferred abundance ratios and limits with respect to C 2 H 2 and HCN are roughly consistent with models of the chemistry in high temperature gas. Models of UV irradiated disk surfaces generally agree better with the data than pure X-ray models. The limit on NH 3 /HCN implies that evaporation of NH 3 -containing ices is only a minor contributor. The inferred abundances and their limits also compare well with those found in comets, suggesting that part of the cometary material may derive from warm inner disk gas. The high resolution simulations show that future instruments on the James Webb Space Telescope (JWST), the Extremely Large Telescopes (ELTs), the Stratospheric Observatory for Infrared Astronomy (SOFIA) and the Space Infrared Telescope for Cosmology and Astrophysics (SPICA) can probe up to an order of magnitude lower abundance ratios and put important new constraints on the models, especially if pushed to high S/Ns.

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“…Chemistry in protoplanetary disks has been studied by various authors in recent years (for a review, see Markwick & Charnley 2004a). It is important to study these objects theoretically for reasons related to observations -both current and forthcoming -for example to determine which molecules make good tracers of the disk temperature, density, ionization fraction and radiation field, and to learn how to discriminate between the different models of disk structure currently available.…”

Section: Motivationmentioning

confidence: 99%

“…The temperature and density structure, however, remain crucial. Of the many different models in the literature (see Markwick & Charnley 2004a), most of them use a different disk structure.…”

Section: Recent Successesmentioning

confidence: 99%

Chemical Models of Inner Disks

Markwick-Kemper¹

2006

IAU

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Abstract. In this paper I describe some of the recent advances made in the modelling of chemistry of protoplanetary disks, and in particular, of the inner regions where r < 100 AU. These advances include the treatment of mass-transport processes, the interaction of radiation with chemistry, the augmentation of chemical networks to include isotopic species and their fractionation, and the attempt to connect disk chemistry with solar system bodies like comets. In the spirit of the title of this volume, I also briefly describe what in my opinion are the current challenges facing models of disk chemistry. These include the unification of chemistry, radiation and dynamics, the treatment of gas-grain interaction and the usefulness of observations to discriminate the different models in the literature.

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Chemistry of Protoplanetary Disks

Cited by 13 publications

References 129 publications

Cosmic Carbon Chemistry: From the Interstellar Medium to the Early Earth

Cosmic Carbon Chemistry: From the Interstellar Medium to the Early Earth

Exploring organic chemistry in planet-forming zones

Chemical Models of Inner Disks

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