FU Orionis: The MIDI VLTI Perspective

Quanz, Sascha P.; Henning, Thomas; Bouwman, J.; Ratzka, Thorsten; Leinert, Christoph

doi:10.1086/505857

Cited by 43 publications

(98 citation statements)

References 43 publications

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“…While the SIMBAD database lists a spectral type of G3Iavar, Kenyon et al (2000) changed it to G0II. In contrast to Hanner et al (1998), who measured an increasing MIR flux shortward of 10 μm, the spectra of Schegerer et al (2006) and Quanz et al (2006) agree very well with ours, indicating that this object was not variable in the MIR between Dec. 2002 and Jan. 2006 (or at least that any period of variability was not observed). No Kurucz model was plotted in the SED of FU Ori as explained in Sect.…”

Section: Appendix A: Comments On Individual Sourcessupporting

confidence: 86%

Mid-IR observations of circumstellar disks

Schuetz¹,

Meeus

Sterzik³

et al. 2009

A&A

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We present new mid-infrared spectra of 15 targets (1 FU Orionis object, 4 Herbig Ae stars, 5 T Tauri stars, and 5 Vega-type stars), obtained with the TIMMI2 camera at La Silla Observatory (ESO). Three targets are members of the β Pic moving group (HD 155 555, HD 181 296, and HD 319 139). PAH bands are observed towards the T Tauri star HD 34 700 and the Herbig Ae star PDS 144 N. For HD 34 700, the band profiles indicate processed PAHs. The spectrum of the Vega-type object η Corvi (HD 109 085), for which a resolved disk at sub-mm wavelengths is known, appears stellar between 8-13 μm, but a small excess emission was reported by Spitzer observations. Similarly, no indication of circumstellar matter at mid-infrared wavelengths is found towards the Vega-like stars HD 3003, HD 80 951, HD 181 296, and, surprisingly, the T Tauri system HD 155 555. The silicate emission features of the remaining eight sources are modelled with a mixture of silicates of different grain sizes and composition. Unprocessed dust dominates FU Ori, HD 143 006, and CD-43 344. Large amorphous grains are the main dust component around HD 190 073, HD 319 139, KK Oph, and PDS 144 S. Both small grains and crystalline dust is found for the Vega-type HD 123 356, with a dominance of small amorphous grains. We show that the infrared emission of the binary HD 123 356 is dominated by its late-type secondary, but optical spectroscopy is still required to confirm the age of the system and the spectral class of the companion. For most targets, this is their first mid-infrared spectroscopic observation. We investigate trends between stellar, disk, and silicate properties and confirm correlations identified in previous studies. Several objects present an exciting potential for follow-up high-resolution disk studies.

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Section: Appendix A: Comments On Individual Sourcessupporting

confidence: 86%

Mid-IR observations of circumstellar disks

Schuetz¹,

Meeus

Sterzik³

et al. 2009

A&A

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show abstract

“…This configuration and derived accretion rates were recently confirmed by modeling the infrared spectra of FU Ori stars taken with the Spitzer Space Telescope (Green et al 2006). However, Quanz et al (2006) modeled their mid-IR visibilities of FU Ori without any additional structure such as a dusty envelope and concluded that the presence of an accretion disk is sufficient to explain this object.…”

Section: Fu Ori Accretion Disksmentioning

confidence: 99%

Relation between the Luminosity of Young Stellar Objects and Their Circumstellar Environment

Vinković

Jurkić

2007

ApJ

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We present a new model-independent method of comparison of NIR visibility data of YSOs. The method is based on scaling the measured baseline with the YSO's distance and luminosity, which removes the dependence of visibility on these two variables. We use this method to compare all available NIR visibility data and demonstrate that it distinguishes YSOs of luminosity L ? P 10 3 L (low L) from YSOs of L ? k 10 3 L ( high L). This confirms earlier suggestions, based on fits of image models to the visibility data, for the difference between the NIR sizes of these two luminosity groups. When plotted against the ''scaled'' baseline, the visibility creates the following data clusters: low-L Herbig Ae/ Be stars, T Tauri stars, and high-L Herbig Be stars. We model the shape and size of clusters with different image models and find that low-L Herbig stars are best explained by the uniform brightness ring and the halo model, T Tauri stars with the halo model, and high-L Herbig stars with the accretion disk model. However, the plausibility of each model is not well established. Therefore, we try to build a descriptive model of the circumstellar environment consistent with various observed properties of YSOs. We argue that low-L YSOs have optically thick disks with the optically thin inner dust sublimation cavity and an optically thin dusty outflow above the inner disk regions. High-L YSOs have optically thick accretion disks with high accretion rates enabling gas to dominate the NIR emission over dust. Although observations would favor such a description of YSOs, the required dust distribution is not supported by our current understanding of dust dynamics.

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“…The errors of the MIDI spectra are difficult to estimate properly from the present data sets, because the number of standard stars observed close in time to V Oph and at similar airmasses is quite limited (3, 2, and 3 standard stars at epoch 1, 2, and 3, respectively). However, we estimate the errors of the absolutely calibrated spectra to be 10-20%, based on other studies which derived N-band spectra from MIDI data (e.g., Kervella et al 2006;Poncelet et al 2006;Quanz et al 2006). The data set number of each visibility point as given in Table 1 is indicated.…”

Section: Midi Observationsmentioning

confidence: 99%

Temporal variations of the outer atmosphere and the dust shell of the carbon-rich Mira variable V Ophiuchi probed with VLTI/MIDI

Ohnaka¹,

Driebe²,

Weigelt³

et al. 2007

A&A

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Aims. We present the first multi-epoch N-band spectro-interferometric observations of the carbon-rich Mira variable V Oph using MIDI at the ESO's Very Large Telescope Interferometer. Our aim is to study temporal variations of physical properties of the outer atmosphere and the circumstellar dust shell based on spectrally-dispersed N-band visibilities over the C 2 H 2 (+HCN) features and the dust emission. Methods. Our MIDI observations were carried out at three different phases 0.18, 0.49, and 0.65, with three different baselines (projected baseline lengths of 42-124 m) using four 8.2 m Unit Telescopes (UT2-UT4, UT1-UT4, and UT2-UT3 baseline configurations). Results. The wavelength dependence of the uniform-disk diameters obtained at all epochs is characterized by a roughly constant region between 8 and 10 µm with a slight dip centered at ∼9.5 µm and a gradual increase longward of 10 µm. These N-band angular sizes are significantly larger than the estimated photospheric size of V Oph. The angular sizes observed at different epochs reveal that the object appears smaller at phase 0.49 (minimum light) with uniform-disk diameters of ∼5-12 mas than at phases 0.18 (∼12-20 mas) and 0.65 (∼9-15 mas). We interpret these results with a model consisting of optically thick C 2 H 2 layers and an optically thin dust shell. Our modeling suggests that the C 2 H 2 layers around V Oph are more extended (∼1.7-1.8 R ) at phases 0.18 and 0.65 than at phase 0.49 (∼1.4 R ) and that the C 2 H 2 column densities appear to be the smallest at phase 0.49. We also find that the dust shell consists of amorphous carbon and SiC with an inner radius of ∼2.5 R , and the total optical depths of τ V ≈ 0.6-0.9 (τ 11.3 µm ≈ 0.003 and 0.004 for amorphous carbon and SiC, respectively) found at phases 0.18 and 0.65 are higher than the value obtained at phase 0.49, τ V ≈ 0.3 (τ 11.3 µm ≈ 0.001 and 0.002 for amorphous carbon and SiC, respectively). Conclusions. Our MIDI observations and modeling indicate that carbon-rich Miras also have extended layers of polyatomic molecules as previously confirmed in oxygen-rich Miras. The temporal variation of the N-band angular size is largely governed by the variations of the opacity and the geometrical extension of the C 2 H 2 layers and the dust shell, and consequently, this masks the size variation of the photosphere. Also, the observed weakness of the mid-infrared C 2 H 2 absorption in carbon-rich Miras can be explained by the emission from the extended C 2 H 2 layers and the dust shell.

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FU Orionis: The MIDI VLTI Perspective

Cited by 43 publications

References 43 publications

Mid-IR observations of circumstellar disks

Mid-IR observations of circumstellar disks

Relation between the Luminosity of Young Stellar Objects and Their Circumstellar Environment

Temporal variations of the outer atmosphere and the dust shell of the carbon-rich Mira variable V Ophiuchi probed with VLTI/MIDI

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