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arXiv · 1311.5131

Evidence of a discontinuous disk structure around the Herbig Ae star HD 139 614

Alexis Matter·Lucas Labadie·Alexander Kreplin·Bruno Lopez·Sebastian Wolf·Gerd Weigelt·Steve Ertel·Joerg-Uwe Pott·William C. Danchi
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Abstract

A new class of pre-main sequence objects has been recently identified as pre-transitional disks. They present near-infrared excess coupled to a flux deficit at about 10 microns and a rising mid-infrared and far-infrared spectrum. These features suggest a disk structure with inner and outer dust components, separated by a dust-depleted region (or gap). We here report on the first interferometric observations of the disk around the Herbig Ae star HD 139614. Its infrared spectrum suggests a flared disk, and presents pre-transitional features,namely a substantial near-infrared excess accompanied by a dip around 6 microns and a rising mid-infrared part. In this framework, we performed a study of the spectral energy distribution (SED) and the mid-infrared VLTI/MIDI interferometric data to constrain thespatial structure of the inner dust disk region and assess its possibly multi-component structure. We based our work on a temperature-gradient disk model that includes dust opacity. While we could not reproduce the SED and interferometric visibilities with a one-component disk, a better agreement was obtained with a two-component disk model composed of an optically thin inner disk extending from 0.22 to 2.3 au, a gap, and an outer temperature-gradient disk starting at 5.6 au. Therefore, our modeling favors an extended and optically thin inner dust component and in principle rules out the possibility that the near-infrared excess originates only from a spatially confined region. Moreover, the outer disk is characterized by a very steep temperature profile and a temperature higher than 300 K at its inner edge. This suggests the existence of a warm component corresponding to a scenario where the inner edge of the outer disk is directly illuminated by the central star. This is an expected consequence of the presence of a gap, thus indicative of a pre-transitional structure.

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Alexis Matter, Lucas Labadie, Alexander Kreplin, Bruno Lopez, Sebastian Wolf, Gerd Weigelt, Steve Ertel, Joerg-Uwe Pott, William C. Danchi. 2013-11-20. Evidence of a discontinuous disk structure around the Herbig Ae star HD 139 614. https://doi.org/10.1051/0004-6361%2F201322042

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