A multi-wavelength interferometric study of the massive young stellar object IRAS 13481-6124^⋆

¹ Ural Federal University, Kourovka Astronomical Observatory, 51 Lenin Ave., 620075 Ekaterinburg, Russia
e-mail: pboley@gmail.com
² Max Planck Institute for Radio Astronomy, Auf dem Hügel 69, 53121 Bonn, Germany
³ University of Exeter, Astrophysics Group, Stocker Road, Exeter, EX4 4QL, UK
⁴ European Southern Observatory, Casilla 19001, Santiago 19, Chile
⁵ Max Planck Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany
⁶ LESIA/Observatoire de Paris, CNRS, UPMC, Université Paris Diderot, 5 place Jules Janssen, 92195 Meudon, France
⁷ Sydney Institute of Astronomy, School of Physics, University of Sydney, NSW 2006, Australia
⁸ Department of Astronomy, University of Michigan, 830 Dennison Building, 500 Church St., Ann Arbor, MI 48109, USA
⁹ Thüringer Landessternwarte Tautenburg, Sternwarte 5, 07778 Tautenburg, Germany

Received: 5 October 2015
Accepted: 30 October 2015

Abstract

We present new mid-infrared interferometric observations of the massive young stellar object IRAS 13481-6124, using VLTI/MIDI for spectrally-resolved, long-baseline measurements (projected baselines up to ~120 m) and GSO/T-ReCS for aperture-masking interferometry in five narrow-band filters (projected baselines of ~1.8−6.4 m) in the wavelength range of 7.5−13μm. We combine these measurements with previously-published interferometric observations in the K and N bands in order to assemble the largest collection of infrared interferometric observations for a massive YSO to date. Using a combination of geometric and radiative-transfer models, we confirm the detection at mid-infrared wavelengths of the disk previously inferred from near-infrared observations. We show that the outflow cavity is also detected at both near- and mid-infrared wavelengths, and in fact dominates the mid-infrared emission in terms of total flux. For the disk, we derive the inner radius (~1.8 mas or ~6.5 AU at 3.6 kpc), temperature at the inner rim (~1760 K), inclination (~48°) and position angle (~107°). We determine that the mass of the disk cannot be constrained without high-resolution observations in the (sub-)millimeter regime or observations of the disk kinematics, and could be anywhere from ~10^-3 to 20M_⊙. Finally, we discuss the prospects of interpreting the spectral energy distributions of deeply-embedded massive YSOs, and warn against attempting to infer disk properties from the spectral energy distribution.