ALMA sub-mm maser and dust distribution of VY Canis Majoris
Artikel i vetenskaplig tidskrift, 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.

supergiants

stars: individual: VY CMa

stars: mass-loss

masers

Författare

A. M. S. Richards

University of Manchester

C. M. V. Impellizzeri

Atacama Large Millimeter-submillimeter Array

NRAO

E. M. Humphreys

European Southern Observatory (ESO)

C. Vlahakis

Atacama Large Millimeter-submillimeter Array

Wouter Vlemmings

Chalmers, Rymd- och geovetenskap, Radioastronomi och astrofysik

A. Baudry

Laboratoire d'Astrophysique de Bordeaux

CNRS Centre National de la Recherche Scientifique

Elvire De Beck

Chalmers, Rymd- och geovetenskap, Onsala rymdobservatorium

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

Universite Paris 7- Denis Diderot

Universidad de Chile

F. Kerschbaum

Universität Wien

I. McDonald

University of Manchester

G. J. Melnick

Harvard-Smithsonian Center for Astrophysics

Sebastien Muller

Chalmers, Rymd- och geovetenskap, Onsala rymdobservatorium

D. A. Neufeld

Johns Hopkins University

Eamon O Gorman

Chalmers, Rymd- och geovetenskap, Radioastronomi och astrofysik

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

Ämneskategorier

Astronomi, astrofysik och kosmologi

DOI

10.1051/0004-6361/201425024