Radiative transfer modeling of the dust disk of the Herbig Be star R Monocerotis

Murakawa, K.

doi:10.1051/0004-6361/200811530

Cited by 3 publications

(4 citation statements)

References 63 publications

(85 reference statements)

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“…The CO line intensity is well correlated with the envelope mass, suggesting possible co-evolution between the envelope and the CO gas. (Boccaletti 2003;Eisner 2004;Monnier et al 2008;Murakawa 2010;Perrin et al 2006;Okamoto et al 2009).…”

Section: Discussionmentioning

confidence: 99%

“…A dual-channel Solid-State Imaging Spectrometer receiver for 230/345 GHz was used as Fuente et al 2006;Hamidouche 2010;Matthews et al 2007;Öberg et al 2010;Schreyer et al 2008;Wang et al 2008). b Circumstellar disks detected by optical or infrared observations (Boccaletti et al 2003;Eisner et al 2004;Monnier et al 2008;Murakawa 2010;Perrin et al 2009;Okamoto et al 2009). …”

Section: Observationsmentioning

confidence: 99%

“…Millimeter observations are needed to probe their surrounding gas properties specifically to investigate the outer part of the disk and determine the mass and grain properties (Alonso-Albi et al 2009). Recently, a handful of disks around HAe/Be stars have been spatially and spectrally resolved by optical and infrared (Boccaletti et al 2003;Eisner et al 2004;Monnier et al 2008;Murakawa 2010;Perrin et al 2009;Okamoto et al 2009), as well as millimeter and submillimeter interferometric observations (Alonso-Albi et al 2009;Fuente et al 2006;Hamidouche 2010;Matthews et al 2007;Öberg et al 2010;Schreyer et al 2008;Wang et al 2008). However, the number of disks well studied at millimeter and submillimeter wavelengths is still very small, and more samples are needed.…”

Section: Introductionmentioning

confidence: 99%

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EVOLUTION OF THE DUST/GAS ENVIRONMENT AROUND HERBIG Ae/Be STARS

Zhang

Qin

et al. 2011

ApJ

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Using the KOSMA 3 m telescope, 54 Herbig Ae/Be (HAe/Be) stars were surveyed in CO and 13 CO emission lines. The properties of the stars and their circumstellar environments were studied by fitting spectral energy distributions (SEDs). The mean line width of 13 CO (2−1) lines of this sample is 1.87 km s −1 . The average column density of H 2 is found to be 4.9 × 10 21 cm −2 for stars younger than 10 6 yr, while this drops to 2.5 × 10 21 cm −2 for those older than 10 6 yr. No significant difference is found among the SEDs of HAe and HBe stars of the same age. Infrared excess decreases with age, envelope masses and envelope accretion rates decease with age after 10 5 yr, the average disk mass of the sample is 3.3 × 10 −2 M , the disk accretion rate decreases more slowly than the envelope accretion rate, and a strong correlation between the CO line intensity and the envelope mass is found.

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Section: Discussionmentioning

confidence: 99%

Section: Observationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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EVOLUTION OF THE DUST/GAS ENVIRONMENT AROUND HERBIG Ae/Be STARS

Zhang

Qin

et al. 2011

ApJ

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“…A comprehensive discussion on the morphology can be found in SC07. Our modeling approach is basically similar to our previous work (Murakawa et al 2010a;Murakawa 2010b). We used NIR polarimetric data obtained with VLT/NACO, these data are particularly useful to estimate the dust sizes.…”

Section: Dust Shell Modelingmentioning

confidence: 99%

Investigation of dust properties of the proto-planetary nebula IRAS 18276−1431

Murakawa

Izumiura²,

Oudmaijer

et al. 2013

Monthly Notices of the Royal Astronomical Society

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We investigate the circumstellar dust properties of the oxygen-rich bipolar protoplanetary nebula IRAS 18276-1431 by means of two-dimensional radiative transfer simulations of the circumstellar dust shell. The model geometry is assumed to have a torus and an envelope which consists of a pair of bipolar lobes and a spherical AGB shell. The parameters of the dust and the dust shell are constrained by comparing the spectral energy distribution (SED) and near-infrared intensity and polarisation data with the models. The polarisation in the envelope reaches 50 -60 % and is nearly constant in the H and K S bands in the observations. This weak wavelength dependence of the polarisation can be reproduced with a grain size distribution function for the torus: 0.05 µm a with n (a) ∝ a −(p=5.5) exp (−a/a c = 0.3 µm). The power index p is significantly steeper than that for interstellar dust (p ∼ 3). Similar results have also been found in some other PPNs and suggest that mechanisms that grind down large particles, such as sputtering, may also have acted when the dust particles formed. The spectral opacity index β is found to be 0.6±0.5 from the 760 µm to 2.6 mm fluxes, which is characterised by the dust in the torus. This low value (<2) indicates the presence of large dust grains in the torus. We discuss two possible dust models for the torus. One has a size distribution function of 1.0 µm a a max = 5 000.0 µm with n (a) ∝ a −(p=2.5) and the other is 1.0 µm a a max = 10 000.0 µm with n (a) ∝ a −(p=3.5) . The former has β of 0.633, but we are not able to find reasonable geometry parameters to fit the SED in the infrared. The latter has β of 1.12, but reproduces the SED better over a wide wavelength range. With this dust model, the geometric parameters are estimated as follows: the inner and outer radii are 30 AU and 1000 AU and the torus mass is 3.0 M ⊙ . Given that the torii are generally not found to be rotating, a large fraction of the torus material is likely to be expanding. Assuming an expansion velocity of 15 kms −1 , the torus formation time and mass-loss rate are found to be ∼300 yrs and ∼10 −2 M ⊙ yr −1 respectively.

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Mid-infrared interferometry of the massive young stellar object NGC 2264 IRS 1

Grellmann

Ratzka

Kraus

et al. 2011

A&A

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Context. The optically invisible infrared-source NGC 2264 IRS 1 lying north of the Cone Nebula is thought to be a massive young stellar object (∼10 M ). Although strong infrared excess clearly shows that the central object is surrounded by large amounts of circumstellar material, no information about the spatial distribution of this circumstellar material has been available until now. Aims. We used the ESO Very Large Telescope Interferometer to perform long-baseline interferometric observations of NGC 2264 IRS 1 in the mid-infrared regime. Our observations resolve the circumstellar material around NGC 2264 IRS 1, provide the first direct measurement of the angular size of the mid-infrared emission, and yield direct constraints on the spatial distribution of the dust. Methods. We analyze the spectrally dispersed interferometric data taken with MIDI at two different position angles and baseline lengths. We use different approaches (a geometrical model, a temperature-gradient model, and radiative transfer models) to jointly model the observed interferometric visibilities and the spectral energy distribution. Results. The derived visibility values between ∼0.02 and ∼0.3 show that the mid-infrared emission is clearly resolved. The characteristic size of the MIR-emission region is ∼30−60 AU; this value is typical for other YSOs with similar or somewhat lower luminosities. A comparison of the sizes for the two position angles shows a significant elongation of the dust distribution. Simple spherical envelope models are therefore inconsistent with the data. The radiative transfer modeling of our data suggests that we observe a geometrically thin and optically thick circumstellar disk with a mass of about 0.1 M . Conclusions. Our modeling indicates that NGC 2264 IRS 1 is surrounded by a flat circumstellar disk that has properties similar to disks typically found around lower-mass young stellar objects. This result supports the assumption that massive young stellar objects form via accretion from circumstellar disks.

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Radiative transfer modeling of the dust disk of the Herbig Be star R Monocerotis

Cited by 3 publications

References 63 publications

EVOLUTION OF THE DUST/GAS ENVIRONMENT AROUND HERBIG Ae/Be STARS

EVOLUTION OF THE DUST/GAS ENVIRONMENT AROUND HERBIG Ae/Be STARS

Investigation of dust properties of the proto-planetary nebula IRAS 18276−1431

Mid-infrared interferometry of the massive young stellar object NGC 2264 IRS 1

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