Large dust particles in disks around T Tauri stars

Rodmann, J.; Henning, Th.; Chandler, Claire J.; Mundy, Lee G.; Wilner, David J.

doi:10.1051/0004-6361:20054038

Cited by 233 publications

(295 citation statements)

References 50 publications

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“…We fixed the slope of the grain size distribution: dn(a) ∝ a −3 da, with minimum grain size a min = 0.1 μm and maximum grain size a max = 1 cm. This range is consistent with the values inferred from the analysis of SED slopes at millimeter wavelengths of T Tauri disks (Rodmann et al 2006;Lommen et al 2007;Ricci et al 2010;Ubach et al 2012 (Zubko et al 1996), and water ices (Warren 1984), with fractional abundances from a simplification of the model used in Pollack et al (1994) and a volume fraction for vacuum of ∼30%. 4.…”

Section: Modeling Setupsupporting

confidence: 87%

TheHerschelGould Belt Survey in Chamaeleon II

Spezzi

Cox

Prusti

et al. 2013

A&A

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Context. We report on the Herschel Gould Belt survey (HGBS) of the Chamaeleon II (Cha II) star-forming region, focusing on the detection of Class I to III young stellar objects (YSOs). Aims. We aim at characterizing the circumstellar material around these YSOs and at understanding which disk parameters are most likely constrained by the new HGBS data, which are expected to be crucial for studying the transition from optically thick disks to evolved debris-type disks. Methods. We recovered 29 of the 63 known YSOs in Cha II with a detection in at least one of the PACS/SPIRE pass-bands: 3 Class I YSOs (i.e.,100%), 1 flat source (i.e., 50%), 21 Class II objects (i.e., 55%), 3 Class III objects (i.e, 16%), and the unclassified farinfrared source IRAS 12522-7640. We explored PACS/SPIRE colors of this sample and modeled their spectral energy distributions (SEDs) from the optical to Herschel's wavelengths with the RADMC-2D radiative transfer code. Results. We find that YSO colors are typically confined to the following ranges: −0.7 log (F 70 /F 160 ) 0.5, −0.5 log (F 160 /F 250 ) 0.6, 0.05 log(F 250 /F 350 ) 0.25 and −0.1 log (F 350 /F 500 ) 0.5. These color ranges are expected to be only marginally contaminated by extragalactic sources and field stars and, hence, provide a useful YSO selection tool when applied together. We were able to model the SED of 26 of the 29 detected YSOs. We discuss the degeneracy/limitations of our SED fitting results and adopted the Bayesian method to estimate the probability of different values for the derived disk parameters. The Cha II YSOs present typical disk inner radii 0.1 AU, as previously estimated in the literature on the basis of Spitzer data. Our probability analysis shows that, thanks to the new Herschel data, the lower limits to the disk mass (M disk ) and characteristic radius (R C ) are well constrained, while the flaring angle (1 + φ) is only marginally constrained. The lower limit to R C is typically around 50 AU. The lower limits to M disk are proportional to the stellar masses with a typical 0.3% ratio, i.e., in the range estimated in the literature for young Class II stars and brown dwarfs across a broad range of stellar masses. The estimated flaring angles, although very uncertain, point toward very flat disks (1 + φ 1.2), as found for low-mass M-type YSO samples in other star-forming regions. Thus, our results support the idea that disk properties show a dependence on stellar properties.

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Section: Modeling Setupsupporting

confidence: 87%

TheHerschelGould Belt Survey in Chamaeleon II

Spezzi

Cox

Prusti

et al. 2013

A&A

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“…The disk interior, which is optically thick in N band, contains dust grains with a maximum particle size of a max = 1 mm. A size of a max = 1 mm was found for several T Tauri stars with millimeter observations using the Very Large Array (Rodmann et al 2006). The optical depth was measured for constant radii, from the disk atmosphere vertically to the disk midplane.…”

Section: Canonical Disk Modelmentioning

confidence: 92%

Multiwavelength interferometric observations and modeling of circumstellar disks

Schegerer

Ratzka

Schuller

et al. 2013

A&A

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Aims. We investigate the structure of the innermost region of three circumstellar disks around pre-main sequence stars HD 142666, AS 205 N, and AS 205 S. We determine the inner radii of the dust disks and, in particular, search for transition objects where dust has been depleted and inner disk gaps have formed at radii of a few tenths of AU up to several AU. Methods. We performed interferometric observations with IOTA, AMBER, and MIDI in the infrared wavelength ranges 1.6−2.5 μm and 8−13 μm with projected baseline lengths between 25 m and 102 m. The data analysis was based on radiative transfer simulations in 3D models of young stellar objects (YSOs) to reproduce the spectral energy distribution and the interferometric visibilities simultaneously. Accretion effects and disk gaps could be considered in the modeling approach. Results from previous studies restricted the parameter space. Results. The objects of this study were spatially resolved in the infrared wavelength range using the interferometers. Based on these observations, a disk gap could be found for the source HD 142666 that classifies it as transition object. There is a disk hole up to a radius of R in = 0.30 AU and a (dust-free) ring between 0.35 AU and 0.80 AU in the disk of HD 142666. The classification of AS 205 as a system of classical T Tauri stars could be confirmed using the canonical model approach, i.e., there are no hints of disk gaps in our observations.

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“…3. The 7-mm data are excluded because free-free emission from ionized gas contaminates disk emission, with free-free emission typically contributing ∼20% of the 7 mm flux (Rodmann et al 2006). Simultaneous cm observations are required to constrain the free-free emission at 7 mm, which is variable on short timescales ( a few days, see Lommen et al 2009).…”

Section: Disks Sub-mm and MM Data From The Literaturementioning

confidence: 99%

Dust properties of protoplanetary disks in the Taurus-Auriga star forming region from millimeter wavelengths

Ricci¹,

Testi

Natta

et al. 2010

A&A

340

364

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We present the most sensitive 3 mm-survey to date of protoplanetary disks carried out in the Taurus-Auriga star forming region (average rms of about 0.3 mJy), using the IRAM PdBI. With our high detection rate of 17/19 we provide the first detections at wavelengths longer than about 1 mm for 12 sources. This enables us to statistically study the mm SED slopes and dust properties of faint disks and compare them to brighter disks using a uniform analysis method. With these new data and literature measurements at sub-millimeter and millimeter wavelengths, we analyze the dust properties of a sample of 21 isolated disks around T Tauri stars in the Taurus-Auriga star forming region. Together with the information about the disks' spatial extension from sub/mm-mm interferometric studies, we derive from the observed sub-mm/mm spectral energy distribution constraints on the dust opacity law at these wavelengths, using two-layer flared disk models and a self-consistent dust model that properly takes into account the variation of the dust opacity with grain growth. We find evidence for the presence of dust particles in the disk midplane that have grown to sizes as large as at least 1 millimeter in all the disks of our sample, confirming what was previously observed on smaller brighter objects. This indicates that the dust coagulation from ISM dust to mm-sized grains is a very fast process in protoplanetary disks, which appears to occur before a young stellar object enters the class II evolutionary stage. The amount of these large grains in the disk outer regions is also found to be stationary throughout the whole class II evolutionary stage, which indicates that mechanisms slowing down the dust inward migration play an important role in the Taurus-Auriga protoplanetary disks. Another result is that the spectral index between 1 and 3 mm for the six faintest disks in our sample is on average smaller than for the brighter disks, indicating either that these fainter yet unmapped disks are spatially much less extended than the brighter spatially resolved disks, or that fainter disks have typically larger dust grains in their outer regions. Considering that these fainter disks are more representative of the bulk of the disk population than the brighter ones, this may have important consequences for the theories of planetesimal formation and disk formation and evolution. Finally, we investigate the relations between the derived dust properties, namely dust mass and grain growth, and the properties of the central star, like its mass, age and mass accretion rate.

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Large dust particles in disks around T Tauri stars

Cited by 233 publications

References 50 publications

TheHerschelGould Belt Survey in Chamaeleon II

TheHerschelGould Belt Survey in Chamaeleon II

Multiwavelength interferometric observations and modeling of circumstellar disks

Dust properties of protoplanetary disks in the Taurus-Auriga star forming region from millimeter wavelengths

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