An impressionist view of V Hydrae: When MATISSE paints asymmetric giant blobs
Journal article, 2024
Context. Asymptotic giant branch (AGB) stars enrich the interstellar medium through their mass loss. The mechanism(s) shaping the circumstellar environment of mass-losing stars is not clearly understood so far. Aims. Our purpose is to study the effect of binary companions located within the first 10 stellar radii from the primary AGB star. In this work, we target the mass-losing carbon star V Hydrae (V Hya) and search for signatures of its companion in the dust-forming region of the atmosphere.
Methods. The star was observed in the L and N bands with the VLTI/MATISSE instrument at low spectral resolution. We reconstructed images of the photosphere and surroundings of V Hya using the two bands and compared our interferometric observables with VLTI/MIDI and VISIR archival data. To constrain the dust properties, we used the 1D radiative transfer code DUSTY to model the spectral energy distribution.
Results. The star is dominated by dust emission in the L- and N-bands. The MATISSE reconstructed images show asymmetric and elongated structures in both infrared bands. In the L band, we detected an elongated shape of approximately 15 mas that likely is of photospheric origin. In the N band, we found a 20 mas extension northeast from the star and perpendicular to the L-band elongated axis. The position angle and the size of the N-band extension match the prediction of the companion position at the MATISSE epoch. By comparing MATISSE N-band with MIDI data, we deduce that the elongation axis in the N-band has rotated since the previous interferometric measurements 13 yr ago, supporting the idea that the particle enhancement is related to the dusty clump moving along with the companion. The VISIR image confirms the presence of a large-scale dusty circumstellar envelope surrounding V Hya.
Conclusions. The MATISSE images unveil the presence of a dust enhancement at the position of the companion. This opens new doors for further analyses of the binary interaction with an AGB component.
Methods. The star was observed in the L and N bands with the VLTI/MATISSE instrument at low spectral resolution. We reconstructed images of the photosphere and surroundings of V Hya using the two bands and compared our interferometric observables with VLTI/MIDI and VISIR archival data. To constrain the dust properties, we used the 1D radiative transfer code DUSTY to model the spectral energy distribution.
Results. The star is dominated by dust emission in the L- and N-bands. The MATISSE reconstructed images show asymmetric and elongated structures in both infrared bands. In the L band, we detected an elongated shape of approximately 15 mas that likely is of photospheric origin. In the N band, we found a 20 mas extension northeast from the star and perpendicular to the L-band elongated axis. The position angle and the size of the N-band extension match the prediction of the companion position at the MATISSE epoch. By comparing MATISSE N-band with MIDI data, we deduce that the elongation axis in the N-band has rotated since the previous interferometric measurements 13 yr ago, supporting the idea that the particle enhancement is related to the dusty clump moving along with the companion. The VISIR image confirms the presence of a large-scale dusty circumstellar envelope surrounding V Hya.
Conclusions. The MATISSE images unveil the presence of a dust enhancement at the position of the companion. This opens new doors for further analyses of the binary interaction with an AGB component.
Stars: individual: V Hydrae
Stars: carbon
Stars: mass-loss
Techniques: interferometric
Stars: AGB and post-AGB
Author
L. Planquart
European Southern Observatory Santiago
Université libre de Bruxelles (ULB)
C. Paladini
European Southern Observatory Santiago
A. Jorissen
Université libre de Bruxelles (ULB)
A. Escorza
European Southern Observatory Santiago
University of La Laguna
Instituto de Astrofísica de Canarias
E. Pantin
University Paris-Saclay
J. Drevon
Observatoire de la Cote d'Azur
European Southern Observatory Santiago
B. Aringer
University of Vienna
F. Baron
Georgia State University
A. Chiavassa
Observatoire de la Cote d'Azur
P. Cruzalèbes
Observatoire de la Cote d'Azur
W. Danchi
NASA Goddard Space Flight Center
Elvire De Beck
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
M. A. T. Groenewegen
Royal Observatory of Belgium
S. Höfner
Uppsala University
J. Hron
University of Vienna
Theo Khouri
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
B. Lopez
Observatoire de la Cote d'Azur
F. Lykou
Hungarian Academy of Sciences
M. Montargès
Paris Observatory
N. Nardetto
Observatoire de la Cote d'Azur
K. Ohnaka
Universidad Andrés Bello
Hans Olofsson
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
G. Rau
NASA Goddard Space Flight Center
A. Rosales-Guzmán
Universidad Nacional Autónoma de México
J. Sanchez-Bermudez
Universidad Nacional Autónoma de México
P. Scicluna
European Southern Observatory Santiago
L. Siess
Université libre de Bruxelles (ULB)
F. Thévenin
Observatoire de la Cote d'Azur
S. Van Eck
Université libre de Bruxelles (ULB)
Wouter Vlemmings
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
G. Weigelt
Max Planck Society
M. Wittkowski
European Southern Observatory (ESO)
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 687 A306Subject Categories
Astronomy, Astrophysics and Cosmology
DOI
10.1051/0004-6361/202348226