TY - JOUR
T1 - Multi-wavelength VLTI study of the puffed-up inner rim of a circumbinary disc
AU - Corporaal, A.
AU - Kluska, J.
AU - Van Winckel, H.
AU - Bollen, D.
AU - Kamath, D.
AU - Min, M.
PY - 2021/6/16
Y1 - 2021/6/16
N2 - Context. The presence of stable, compact circumbinary discs of gas and dust around post-asymptotic giant branch (post-AGB) binary systems has been well established. We focus on one such system, IRAS 08544-4431.Aims. We present an interferometric multi-wavelength analysis of the circumstellar environment of IRAS 08544-4431. The aim is to constrain different contributions to the total flux in the H-, K-, L-, and N-bands in the radial direction.Methods. The data obtained with the three current instruments on the Very Large Telescope Interferometer (VLTI), VLTI/PIONIER, VLTI/GRAVITY, and VLTI/MATISSE, range from the near-infrared, where the post-AGB star dominates, to the mid-infrared, where the disc dominates. We fitted the following two geometric models to the visibility data to reproduce the circumbinary disc: A ring with a Gaussian width and a flat disc model with a temperature gradient. The flux contributions from the disc, the primary star (modelled as a point source), and an over-resolved component were recovered along with the radial size of the emission, the temperature of the disc as a function of radius, and the spectral dependencies of the different components.Results. The trends of all visibility data were well reproduced with the geometric models. The near-infrared data were best fitted with a Gaussian ring model, while the mid-infrared data favoured a temperature gradient model. This implies that a vertical structure is present at the disc inner rim, which we attribute to a rounded puffed-up inner rim. The N-to-K size ratio is 2.8, referring to a continuous flat source, analogues to young stellar objects.Conclusions. By combining optical interferometric instruments operating at different wavelengths, we can resolve the complex structure of circumstellar discs and study the wavelength-dependent opacity profile. A detailed radial, vertical, and azimuthal structural analysis awaits a radiative transfer treatment in 3D to capture all non-radial complexity.
AB - Context. The presence of stable, compact circumbinary discs of gas and dust around post-asymptotic giant branch (post-AGB) binary systems has been well established. We focus on one such system, IRAS 08544-4431.Aims. We present an interferometric multi-wavelength analysis of the circumstellar environment of IRAS 08544-4431. The aim is to constrain different contributions to the total flux in the H-, K-, L-, and N-bands in the radial direction.Methods. The data obtained with the three current instruments on the Very Large Telescope Interferometer (VLTI), VLTI/PIONIER, VLTI/GRAVITY, and VLTI/MATISSE, range from the near-infrared, where the post-AGB star dominates, to the mid-infrared, where the disc dominates. We fitted the following two geometric models to the visibility data to reproduce the circumbinary disc: A ring with a Gaussian width and a flat disc model with a temperature gradient. The flux contributions from the disc, the primary star (modelled as a point source), and an over-resolved component were recovered along with the radial size of the emission, the temperature of the disc as a function of radius, and the spectral dependencies of the different components.Results. The trends of all visibility data were well reproduced with the geometric models. The near-infrared data were best fitted with a Gaussian ring model, while the mid-infrared data favoured a temperature gradient model. This implies that a vertical structure is present at the disc inner rim, which we attribute to a rounded puffed-up inner rim. The N-to-K size ratio is 2.8, referring to a continuous flat source, analogues to young stellar objects.Conclusions. By combining optical interferometric instruments operating at different wavelengths, we can resolve the complex structure of circumstellar discs and study the wavelength-dependent opacity profile. A detailed radial, vertical, and azimuthal structural analysis awaits a radiative transfer treatment in 3D to capture all non-radial complexity.
KW - Binaries: General
KW - Circumstellar matter
KW - Protoplanetary disks
KW - Stars: AGB and post-AGB
KW - Techniques: Interferometric
UR - http://www.scopus.com/inward/record.url?scp=85108256623&partnerID=8YFLogxK
U2 - 10.1051/0004-6361/202141154
DO - 10.1051/0004-6361/202141154
M3 - Article
AN - SCOPUS:85108256623
SN - 0004-6361
VL - 650
SP - 1
EP - 8
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
M1 - L13
ER -