ALMA sub-mm maser and dust distribution of VY Canis Majoris
Journal article, 2014

Aims. Cool, evolved stars have copious, enriched winds. Observations have so far not fully constrained models for the shaping and acceleration of these winds. We need to understand the dynamics better, from the pulsating stellar surface to similar to 10 stellar radii, where radiation pressure on dust is fully effective. Asymmetric nebulae around some red supergiants imply the action of additional forces. Methods. We retrieved ALMA Science Verification data providing images of sub-mm line and continuum emission from VY CMa. This enables us to locate water masers with milli-arcsec accuracy and to resolve the dusty continuum. Results. The 658, 321, and 325 GHz masers lie in irregular, thick shells at increasing distances from the centre of expansion. For the first time this is confirmed as the stellar position, coinciding with a compact peak offset to the NW of the brightest continuum emission. The maser shells overlap but avoid each other on scales of up to 10 au. Their distribution is broadly consistent with excitation models but the conditions and kinematics are complicated by wind collisions, clumping, and asymmetries.

masers

stars: mass-loss

supergiants

stars: individual: VY CMa

Author

A. M. S. Richards

University of Manchester

C. M. V. Impellizzeri

Atacama Large Millimeter-submillimeter Array (ALMA)

NRAO

E. M. Humphreys

European Southern Observatory (ESO)

C. Vlahakis

Atacama Large Millimeter-submillimeter Array (ALMA)

Wouter Vlemmings

Chalmers, Earth and Space Sciences, Radio Astronomy and Astrophysics

A. Baudry

Laboratoire d'Astrophysique de Bordeaux

Centre national de la recherche scientifique (CNRS)

Elvire De Beck

Chalmers, Earth and Space Sciences, Onsala Space Observatory

L. Decin

KU Leuven

S. Etoka

Universität Hamburg

M. D. Gray

University of Manchester

G. M. Harper

Trinity College Dublin

T. R. Hunter

NRAO

P. Kervella

UMI-FCA

University of Chile (UCH)

Paris Diderot University

F. Kerschbaum

University of Vienna

I. McDonald

University of Manchester

G. J. Melnick

Harvard-Smithsonian Center for Astrophysics

Sebastien Muller

Chalmers, Earth and Space Sciences, Onsala Space Observatory

D. A. Neufeld

Johns Hopkins University

Eamon O Gorman

Chalmers, Earth and Space Sciences, Radio Astronomy and Astrophysics

S. Y. Parfenov

Ural Federal University

A. B. Peck

NRAO

H. Shinnaga

NAOJ

A. M. Sobolev

Ural Federal University

L. Testi

European Southern Observatory (ESO)

L. Uscanga

National Observatory of Athens

A. Wootten

NRAO

J. A. Yates

University College London (UCL)

A. Zijlstra

University of Manchester

Astronomy and Astrophysics

0004-6361 (ISSN) 1432-0746 (eISSN)

Vol. 572 L9

Subject Categories

Astronomy, Astrophysics and Cosmology

DOI

10.1051/0004-6361/201425024

More information

Latest update

9/7/2018 1