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Paper: The Innermost Circumstellar Environment of Massive Young Stellar Objects Revealed by Infrared Interferometry
Volume: 387, Massive Star Formation: Observations Confront Theory
Page: 140
Authors: Preibisch, T.; Kraus, S.; Ohnaka, K.
Abstract: We study the geometry of the inner (AU-scale) circumstellar region around the Herbig Be star MWC 147 with infrared long-baseline interferometry. By combining for the first time near- and mid-infrared spectro-interferometry on a Herbig star, our VLTI/AMBER and VLTI/MIDI data constrain not only the geometry of the brightness distribution, but also the radial temperature distribution in the disk. The emission from MWC 147 is clearly resolved and has a characteristic physical size of ∼ 1.3 AU and ∼ 9 AU at 2.2 μm and 11 μm, respectively. This increase in apparent size towards longer wavelengths is much steeper than predicted by analytic disk models assuming power-law radial temperature distributions. For a detailed modeling of the interferometric data and the spectral energy distribution of MWC 147, we employ 2-D frequency-dependent radiation transfer simulations. This analysis shows that passive, irradiated Keplerian dust disks can easily fit the SED, but predict much lower visibilities than observed, so these models can clearly be ruled out. Models of a Keplerian disk with emission from an inner gaseous accretion disk (inside the dust sublimation zone), however, yield a good fit of the SED and simultaneously reproduce the observed near- and mid-infrared visibilities reasonably well. We conclude that the near-infrared emission from MWC 147 is dominated by accretion luminosity emerging from an inner gaseous disk, while the mid-infrared emission also contains strong contributions from the passive, irradiated dust disk.
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