The deuterium abundance in the local interstellar medium

Prodanovic, Tijana; Steigman, Gary; Fields, Brian D.

doi:10.1111/j.1365-2966.2010.16734.x

Cited by 72 publications

(121 citation statements)

References 46 publications

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“…Wood et al 2004;Sonneborn et al 2000;Prodanović et al 2010). In contrast, molecular D/H ratios have been observed to be several orders of magnitude greater for a number of species (e.g.…”

mentioning

confidence: 90%

An ALMA Survey of DCN/H¹³CN and DCO⁺/H¹³CO⁺ in Protoplanetary Disks

Huang

Öberg

et al. 2017

ApJ

111

171

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“…Wood et al 2004;Sonneborn et al 2000;Prodanović et al 2010). In contrast, molecular D/H ratios have been observed to be several orders of magnitude greater for a number of species (e.g.…”

mentioning

confidence: 90%

An ALMA Survey of DCN/H¹³CN and DCO⁺/H¹³CO⁺ in Protoplanetary Disks

Huang

Öberg

et al. 2017

ApJ

111

171

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“…Prodanović et al (2010) [H] are much smaller than the spread in HD fluxes due to the disk structure. Note that for older star forming regions such as Orion the deuterium abundance is lower, due to the fact that a fraction of the deuterium has been burned up in the cores of stars (Wright et al 1999;Howat et al 2002).…”

Section: Grid Of Modelsmentioning

confidence: 99%

“…The deuterium fraction was taken from Prodanović et al (2010). 1 Spectrum of TW Hya (Cleeves et al 2015).…”

Section: Grid Of Modelsmentioning

confidence: 99%

Far-infrared HD emission as a measure of protoplanetary disk mass

Trapman

Miotello

Kama

et al. 2017

A&A

100

138

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Context. Protoplanetary disks around young stars are the sites of planet formation. While the dust mass can be estimated using standard methods, determining the gas mass -and thus the amount of material available to form giant planets -has proven to be very difficult. Hydrogen deuteride (HD) is a promising alternative to the commonly-used gas mass tracer, carbon monoxide. However, its potential has not yet been investigated with models incorporating both HD and CO isotopologue-specific chemistry, and its sensitivity to uncertainties in disk parameters has not yet been quantified. Aims. To examine the robustness of HD as tracer of the disk gas mass, specifically the effect of gas mass on the HD far infrared emission and its sensitivity to the vertical structure. Also, to provide requirements for future far-infrared missions such as SPICA. Methods. Deuterium chemistry reactions relevant for HD were implemented in the thermochemical code DALI and more than 160 disk models were run for a range of disk masses and vertical structures. Results. The HD J=1-0 line intensity depends directly on the gas mass through a sublinear power law relation with a slope of ∼0.8. Assuming no prior knowledge about the vertical structure of a disk and using only the HD 1-0 flux, gas masses can be estimated to within a factor of two for low mass disks (M disk ≤ 10 −3 M ). For more massive disks, this uncertainty increases to more than an order of magnitude. Adding the HD 2-1 line or independent information about the vertical structure can reduce this uncertainty to a factor of ∼ 3 for all disk masses. For TW Hya, using the radial and vertical structure from Kama et al. (2016b) the observations constrain the gas mass to 6 · 10 −3 M ≤ M disk ≤ 9 · 10 −3 M . Future observations require a 5σ sensitivity of 1.8 · 10 −20 W m −2 (2.5 · 10 −20 W m −2 ) and a spectral resolving power R ≥ 300 (1000) to detect HD 1-0 (HD 2-1) for all disk masses above 10 −5 M with a line-to-continuum ratio ≥ 0.01. Conclusions. These results show that HD can be used as an independent gas mass tracer with a relatively low uncertainty and should be considered as an important science goal for future far-infrared missions.

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“…Such a high rate was also used in the studies cited above, i.e., k + = 1.5 × 10 −9 cm 3 s −1 (e.g., Caselli et al 1998). We take the HD abundance to be twice the elemental D/H-ratio, i.e., Linsky et al 2006;Prodanović et al 2010). Because CO is not found to be depleted in our clumps, we assume that this is also the case for atomic oxygen and use the "standard" abundance relative to H 2 of x(O) = 3.52 × 10 −4 , i.e., comparable to x(CO) (see Caselli et al 1998;Caselli 2002).…”

Section: Ionisation Degreementioning

confidence: 99%

Deuterium fractionation and the degree of ionisation in massive clumps within infrared dark clouds

Miettinen

Hennemann

Linz

2011

A&A

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Context. Massive clumps associated with infrared dark clouds (IRDCs) are promising targets for studying the earliest stages of highmass star and cluster formation. Aims. We aim to determine the degrees of CO depletion, deuterium fractionation, and ionisation in a sample of seven massive clumps associated with IRDCs. Methods. The APEX telescope was used to observe the C 17 O(2−1), H 13 CO + (3−2), DCO + (3−2), N 2 H + (3−2), and N 2 D + (3−2) transitions towards the clumps. The spectral line data were used in conjunction with the previously published and/or archival (sub)millimetre dust continuum observations of the sources. The data were used to derive the molecular column densities and fractional abundances for the analysis of deuterium fractionation and ionisation. Results. The CO molecules do not appear to be significantly depleted in the observed clumps. The DCO + /HCO + and N 2 D + /N 2 H + column density ratios are about 0.0002-0.014 and 0.002-0.028, respectively. The former ratio is found to decrease as a function of gas kinetic temperature. A simple chemical analysis suggests that the lower limit to the ionisation degree is in the range x(e) ∼ 10 −8 −10 −7 , whereas the estimated upper limits range from a few 10 −6 up to ∼10 −4 . Lower limits to x(e) imply that the cosmic-ray ionisation rate of H 2 lies between ζ H 2 ∼ 10 −17 −10 −15 s −1 . These are the first estimates of x(e) and ζ H 2 towards massive IRDCs reported so far. Some additional molecular transitions, mostly around 216 and 231 GHz, were detected towards all sources. In particular, IRDC 18102-1800 MM1 and IRDC 18151-1208 MM2 show relatively line-rich spectra. Some of these transitions might be assigned to complex organic molecules, although the line blending hampers the identification. The C 18 O(2−1) transition is frequently seen in the image band. Conclusions. The finding that CO is not depleted in the observed sources conforms to the fact that they show evidence of star formation activity, which is believed to release CO from the icy grain mantles back into the gas phase. The observed degree of deuteration is lower than in low-mass starless cores and protostellar envelopes. Decreasing deuteration with increasing temperature is likely to reflect the clump evolution. On the other hand, the association with young high-mass stars could enhance ζ H 2 and x(e) above the levels usually found in low-mass star-forming regions. On the scale probed by our observations, ambipolar diffusion cannot be a main driver of clump evolution unless it occurs on timescales 10 6 yr.

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The deuterium abundance in the local interstellar medium

Cited by 72 publications

References 46 publications

An ALMA Survey of DCN/H¹³CN and DCO⁺/H¹³CO⁺ in Protoplanetary Disks

An ALMA Survey of DCN/H¹³CN and DCO⁺/H¹³CO⁺ in Protoplanetary Disks

Far-infrared HD emission as a measure of protoplanetary disk mass

Deuterium fractionation and the degree of ionisation in massive clumps within infrared dark clouds

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The deuterium abundance in the local interstellar medium

Cited by 72 publications

References 46 publications

An ALMA Survey of DCN/H13CN and DCO+/H13CO+ in Protoplanetary Disks

An ALMA Survey of DCN/H13CN and DCO+/H13CO+ in Protoplanetary Disks

Far-infrared HD emission as a measure of protoplanetary disk mass

Deuterium fractionation and the degree of ionisation in massive clumps within infrared dark clouds

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Product

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An ALMA Survey of DCN/H¹³CN and DCO⁺/H¹³CO⁺ in Protoplanetary Disks

An ALMA Survey of DCN/H¹³CN and DCO⁺/H¹³CO⁺ in Protoplanetary Disks