Warm gas at 50 AU in the disk around Herbig Be star HD 100546

Abstract

The disk atmosphere is one of the fundamental elements of theoretical models of a protoplanetary disk. However, the direct observation of the warm gas (>> 100 K) at large radius of a disk (>> 10 AU) is challenging, because the line emission from warm gas in a disk is usually dominated by the emission from an inner disk. Our goal is to detect the warm gas in the disk atmosphere well beyond 10 AU from a central star in a nearby disk system of the Herbig Be star HD 100546. We measured the excitation temperature of the vibrational transition of CO at incremental radii of the disk from the central star up to 50 AU, using an adaptive optics system combined with the high-resolution infrared spectrograph CRIRES at the VLT. The observation successfully resolved the line emission with 0".1 angular resolution, which is 10 AU at the distance of HD 100546. Population diagrams were constructed at each location of the disk, and compared with the models calculated taking into account the optical depth effect in LTE condition. The excitation temperature of CO is 400-500 K or higher at 50 AU away from the star, where the blackbody temperature in equilibrium with the stellar radiation drops as low as 90 K. This is unambiguous evidence of a warm disk atmosphere far away from the central star.

7 pages, 5 figures, A&A in press

References in corpus (6)

• Tracing the inner edge of the disk around HD 100546 with Ro-vibrational CO Emission Lines
• Constraining the structure of the planet-forming region in the disk of the Herbig Be star HD 100546
• Chemistry and line emission from evolving Herbig Ae disks
• Detection of CH+ emission from the disc around HD100546
• A survey for near-infrared H2 emission in Herbig Ae/Be stars: emission from the outer disks of HD 97048 and HD 100546
• Low abundance, strong features: Window-dressing crystalline forsterite in the disk wall of HD 100546

Cited by in corpus (13)

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• Multiple spiral patterns in the transitional disk of HD 100546
• The structure of disks around Herbig Ae/Be stars as traced by CO ro-vibrational emission
• Sulphur monoxide exposes a potential molecular disk wind from the planet-hosting disk around HD100546
• Resolving HD 100546 disc in the mid-infrared: Small inner disc and asymmetry near the gap
• Tracing planet-induced structures in circumstellar disks using molecular lines
• Probing the radial temperature structure of protoplanetary disks with Herschel/HIFI
• CO ro-vibrational lines in HD100546: A search for disc asymmetries and the role of fluorescence
• The protoplanetary disk of FT Tauri: multi-wavelength data analysis and modeling
• Near Infrared High Resolution Spectroscopy and Spectro-astrometry of Gas in Disks around Herbig Ae/Be Stars
• Dusty OB stars in the Small Magellanic Cloud - II: Extragalactic Disks or Examples of the Pleiades Phenomenon?
• On the asymmetry of the OH ro-vibrational lines in HD 100546