The close circumstellar environment of Betelgeuse III. SPHERE/ZIMPOL imaging polarimetry in the visible
Author
dc.contributor.author
Kervella, Pierre
Author
dc.contributor.author
Lagadec, E.
Author
dc.contributor.author
Montarges, M.
Author
dc.contributor.author
Ridgway, S.
Author
dc.contributor.author
Chiavassa, A.
Author
dc.contributor.author
Haubois, X.
Author
dc.contributor.author
Schmid, H.
Author
dc.contributor.author
Langlois, M.
Author
dc.contributor.author
Gallenne, A.
Author
dc.contributor.author
Perrin, G.
Admission date
dc.date.accessioned
2016-06-17T20:59:45Z
Available date
dc.date.available
2016-06-17T20:59:45Z
Publication date
dc.date.issued
2016
Cita de ítem
dc.identifier.citation
Astronomy & Astrophysics Volumen: 585 Número de artículo: A28 (2016)
en_US
Identifier
dc.identifier.other
DOI: 10.1051/0004-6361/201527134
Identifier
dc.identifier.uri
https://repositorio.uchile.cl/handle/2250/139015
General note
dc.description
Artículo de publicación ISI
en_US
Abstract
dc.description.abstract
The physical mechanism through which the outgoing material of massive red supergiants is accelerated above the escape velocity is unclear. Thanks to the transparency of its circumstellar envelope, the nearby red supergiant Betelgeuse gives the opportunity to probe the innermost layers of the envelope of a typical red supergiant down to the photosphere, i. e. where the acceleration of the wind is expected to occur. We took advantage of the SPHERE / ZIMPOL adaptive optics imaging polarimeter to resolve the visible photosphere and close envelope of Betelgeuse. We detect an asymmetric gaseous envelope inside a radius of 2 to 3 times the near-infrared photospheric radius of the star (R-star), and a significant H alpha emission mostly contained within 3 R-star From the polarimetric signal, we also identify the signature of dust scattering in an asymmetric and incomplete dust shell located at a similar radius. The presence of dust so close to the star may have a significant impact on the wind acceleration through radiative pressure on the grains. The 3 R-star radius emerges as a major interface between the hot gaseous and dusty envelopes. The detected asymmetries strengthen previous indications that the mass loss of Betelgeuse is likely tied to the vigorous convective motions in its atmosphere.