ISO Spectroscopy of Gas and Dust: From Molecular Clouds to Protoplanetary Disks

Dishoeck, E. F. van

doi:10.1146/annurev.astro.42.053102.134010

Cited by 264 publications

(153 citation statements)

References 205 publications

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“…12), which can be produced by not considering the PAH emission in the SED models (e.g. van Dishoeck 2004), or by an excess in the dust opacities utilized at these wavelengths, affecting the modeled radiation from the hot component that is absorbed by the cold one. Frequency [Hz] Variations in the cold temperature Fig.…”

Section: Dust Properties Of Massive-star Forming Regions Associated Wmentioning

confidence: 99%

Massive star formation in the GMC G345.5+1.0: spatial distribution of the dust emission

López¹,

Bronfman²,

Nyman³

et al. 2011

A&A

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Context. Massive condensations in giant molecular clouds (GMCs) are linked to the formation of high mass stars, which are the principal source of heavy elements and UV radiation, playing an important role in the evolution of galaxies. Aims. We attemp to make a complete census of massive-star formation within all of GMC G345.5+1.0. This cloud is located one degree above the Galactic plane and at 1.8 kpc from the Sun, thus there is little superposition of dust along the line-of-sight, minimizing confusion effects in identifying individual clumps. Methods. We observed the 1.2 mm continuum emission across the whole GMC using the Swedish-ESO Submillimetre Telescope (SEST) Imaging Bolometer Array (SIMBA) mounted on the SEST. Observations have a spatial resolution of 0.2 pc and cover 1.• 8 × 2.• 2 in the sky with a noise of 20 mJy beam −1 . Results. We identify 201 clumps with diameters between 0.2 and 0.6 pc, masses between 3.0 and 1.3 × 10 3 M , and densities between 5 × 10 3 and 4 × 10 5 cm −3 . The total mass of the clumps is 1.2 × 10 4 M , thus the efficiency in forming these clumps, estimated as the ratio of the total clump mass to the total GMC mass, is ∼0.02. The clump mass distribution for masses between 10 and 10 3 M is well-fitted by a power law dN/dM ∝ M −α , with a spectral mass index α of 1.7 ± 0.1. Given their mass distribution, clumps do not appear to be the direct progenitors of single stars. Comparing the 1.2 mm continuum emission with infrared images taken by the Midcourse Space Experiment (MSX) and by the Spitzer satellite, we find that at least ∼20% of the clumps are forming stars, and at most ∼80% are starless. Six massive-star forming regions (MSFRs) embedded in clumps and associated with IRAS point sources have mean densities of ∼10 5 cm −3 , luminosities >10 3 L , and spectral energy distributions that can be modeled with two dust components at different mean temperatures of 28 ± 5 and 200 ± 10 K.

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Section: Dust Properties Of Massive-star Forming Regions Associated Wmentioning

confidence: 99%

Massive star formation in the GMC G345.5+1.0: spatial distribution of the dust emission

López¹,

Bronfman²,

Nyman³

et al. 2011

A&A

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“…Carbon monoxide is among the most abundant constituents of molecular clouds in both gas (e.g., Dame et al 2001) and condensed phases, i.e., ice mantles covering dust grains (e.g., van Dishoeck 2004). Ices exist in a wide variety of astrophysical environments, from theinter-stellar medium to giant planets, satellites, comets, dense clouds, and protoplanetary disks.…”

Section: Introductionmentioning

confidence: 99%

Chemical Evolution of a Co Ice Induced by Soft X-Rays

Ciaravella

Chen

Cecchi‐Pestellini

et al. 2016

ApJ

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We irradiated a pure carbon monoxide ice with soft X-rays of energies up to 1.2 keV. The experiments were performed using the spherical grating monochromator beamline at the National Synchrotron Radiation Research Center in Taiwan, exploiting both monochromatic (at 0.3 and 0.55 keV) and broader energy (0.25-1.2 keV) fluxes. The infrared spectra of the irradiated ices showed the formation of a number of products such as polycarbon monoand dioxides C n O m , and chains containing up to 10 carbon atoms. While a gentle increase in the energy absorbed by the ice sample is reflected by an increase in the column densities of newly born species, such correlation breaks down at very high fluxes. In this regime the production yield falls down sharply by about a factor of 100. The refractory residue obtained in the broad energy irradiation is a "compromise" between those obtained with proton irradiation of C 3 O 2 and CO ices in previous experiments. Finally, we discuss the possible implications for space chemistry

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“…Far-infrared (Far-IR) spectroscopic observations of young premain-sequence stars have the potential to reveal the gas and dust composition of protoplanetary disks in regions not probed at any other wavelengths (e.g., van Dishoeck 2004;Lorenzetti 2005;Henning et al 2010). The atomic and molecular transitions in the far-IR regime (50−200 μm) span a large range in upper energy level (from a few 10 K to a few 10 3 K) and are sensitive to the warm (a few 10 2 K) upper layers of the disk (n < 10 8 cm −3 ).…”

Section: Introductionmentioning

confidence: 99%

DIGIT survey of far-infrared lines from protoplanetary disks

Fedele

Bruderer

Dishoeck

et al. 2013

A&A

114

146

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We present far-infrared (50−200 μm) spectroscopic observations of young pre-main-sequence stars taken with Herschel/PACS as part of the DIGIT key project. The sample includes 16 Herbig AeBe and 4 T Tauri sources observed in SED mode covering the entire spectral range. An additional 6 Herbig AeBe and 4 T Tauri systems have been observed in SED mode with a limited spectral coverage. Multiple atomic fine structure and molecular lines are detected at the source position:The most common feature is the [O i] 63 μm line detected in almost all of the sources, followed by OH. In contrast with CO, OH is detected toward both Herbig AeBe groups (flared and non-flared sources). An isothermal LTE slab model fit to the OH lines indicates column densities of 10 13 < N OH < 10 16 cm −2 , emitting radii 15 < r < 100 AU and excitation temperatures 100 < T ex < 400 K. We used the non-LTE code RADEX to verify the LTE assumption. High gas densities (n ≥ 10 10 cm −3 ) are needed to reproduce the observations. The OH emission thus comes from a warm layer in the disk at intermediate stellar distances. Warm H 2 O emission is detected through multiple lines toward the T Tauri systems AS 205, DG Tau, S CrA and RNO 90 and three Herbig AeBe systems HD 104237, HD 142527, HD 163296 (through line stacking). Overall, Herbig AeBe sources have higher OH/H 2 O abundance ratios across the disk than do T Tauri disks, from near-to far-infrared wavelengths. Far-infrared CH + emission is detected toward HD 100546 and HD 97048. The slab model suggests moderate excitation (T ex ∼ 100 K) and compact (r ∼ 60 AU) emission in the case of HD 100546.Off-source [O i] emission is detected toward DG Tau, whose origin is likely the outflow associated with this source. The [C ii] emission is spatially extended in all sources where the line is detected. This suggests that not all [C ii] emission is associated with the disk and that there is a substantial contribution from diffuse material around the young stars. The flux ratios of the atomic fine structure linesare analyzed with PDR models and require high gas density (n 10 5 cm −3 ) and high UV fluxes (G o ∼ 10 3 −10 7 ), consistent with a disk origin for the oxygen lines for most of the sources.

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ISO Spectroscopy of Gas and Dust: From Molecular Clouds to Protoplanetary Disks

Cited by 264 publications

References 205 publications

Massive star formation in the GMC G345.5+1.0: spatial distribution of the dust emission

Massive star formation in the GMC G345.5+1.0: spatial distribution of the dust emission

Chemical Evolution of a Co Ice Induced by Soft X-Rays

DIGIT survey of far-infrared lines from protoplanetary disks

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