H${}_2$D${}^{+}$ line emission in Proto-Planetary Disks

Abstract

%Context: {Previous studies have indicated that the 372.4 GHz ground transition of ortho-H${}_2$D${}^{+}$ might be a powerful probe of Proto-Planetary Disks. The line could be especially suited for study of the disk mid-plane, where the bulk of the mass resides and where planet formation takes place.} %Aims: {Provide detailed theoretical predictions for the line intensity, profile and maps expected for representative disk models.} %Methods: {We determine the physical and chemical structure of the disks from the model developed by Ceccarelli & Dominik (2005). The line emission is computed with the new radiative transfer method developed recently by Elitzur & Asensio Ramos (2006).} %Results: {We present intensity maps convolved with the expected ALMA resolution, which delineate the origin of the H${}_2$D${}^{+}$ 372.4 GHz line. In the disk inner regions, the line probes the conditions in the mid-plane out to radial distances of a few tens of AU, where Solar-like planetary systems might form. In the disk outermost regions, the line originates from slightly above the mid-plane. When the disk is spatially resolved, the variation of line profile across the image provides important information about the velocity field. Spectral profiles of the entire disk flux show a double peak shape at most inclination angles.} %Conclusions: {Our study confirms that the 372.4 GHz H${}_2$D${}^{+}$ line provides powerful diagnostics of the mid-plane of Proto-Planetary Disks. Current submillimeter telescopes are capable of observing this line, though with some difficulties. The future ALMA interferometer will have the sensitivity to observe and even spatially resolve the H${}_2$D${}^{+}$ line emission.}

To appear in A&A

References in corpus (17)

• Passive irradiated circumstellar disks with an inner hole
• Flaring vs. self-shadowed disks: the SEDs of Herbig Ae/Be stars
• Photoevaporation of Circumstellar Disks due to External FUV Radiation in Stellar Aggregates
• N2H+ and C18O Depletion in a Cold Dark Cloud
• Abundant H2D+ in the pre-stellar core L1544
• The importance of the ortho:para H2 ratio for the deuteration of molecules during pre-protostellar collapse
• Formation and Evolution of Planetary Systems: Upper Limits to the Gas Mass in Disks Around Sun-like Stars
• Detection of D2H+ in the Dense Interstellar Medium
• Reduction of chemical networks. II. Analysis of the fractional ionisation in protoplanetary discs
• The chemistry of multiply deuterated molecules in protoplanetary disks. I. The outer disk
• Detection of interstellar H_2D^+ emission
• The Distribution of Ortho-H_2D+(1_1,0 - 1_1,1) in L1544: Tracing the Deuteration Factory in Prestellar Cores
• Deuterated H${}_3^{+}$ in proto-planetary disks
• A New Exact Method for Line Radiative Transfer
• Line profiles of molecular ions toward the pre-stellar core LDN 1544
• Detection of H2D+ in a massive prestellar core in Orion B
• Probable detection of H2D+ in the starless core Barnard 68

Cited by in corpus (9)

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• The Ionization Fraction in the DM Tau Protoplanetary Disk
• A deep search for H2D+ in protoplanetary disks
• MOLPOP-CEP: An Exact, Fast Code for Multi-Level Systems
• The Foggy Disks Surrounding Herbig Ae Stars: a Theoretical Study of the H2O Line Spectra
• Rotating Disks and Non-Kinematic Double Peaks
• A computed line list for the H2D+ molecular ion