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Dissecting the AGB star L-2 Puppis: a torus in the making
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2015 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 576, UNSP A46Article in journal (Refereed) Published
Abstract [en]

Aims. The circumstellar environment of L-2 Pup, an oxygen-rich semiregular variable, was observed to understand the evolution of mass loss and the shaping of ejecta in the late stages of stellar evolution. Methods. High-angular resolution observations from a single 8 m telescope were obtained using aperture masking in the near-infrared (1.64, 2.30 and 3.74 mu m) on the NACO/VLT, both in imaging and polarimetric modes. Results. The aperture-masking images of L-2 Pup at 2.30 mu m show a resolved structure that resembles a toroidal structure with a major axis of similar to 140 milliarcseconds (mas) and an east-west orientation. Two clumps can be seen on either side of the star, similar to 65 mas from the star, beyond the edge of the circumstellar envelope (estimated diameter is similar to 27 mas), while a faint, hook-like structure appear toward the northeast. The patterns are visible both in the imaging and polarimetric mode, although the latter was only used to measure the total intensity (Stokes I). The overall shape of the structure is similar at the 3.74 mu m pseudo-continuum (dust emission), where the clumps appear to be embedded within a dark, dusty lane. The faint, hook-like patterns are also seen at this wavelength, extending northeast and southwest with the central, dark lane being an apparent axis of symmetry. We interpret the structure as a circumstellar torus with inner radius of 4.2 au. With a rotation velocity of 10 kms(-1) as suggested by the SiO maser profile, we estimate a stellar mass of 0.7 M-circle dot.

Place, publisher, year, edition, pages
2015. Vol. 576, UNSP A46
Keyword [en]
techniques: high angular resolution, methods: observational, stars: AGB and post-AGB, circumstellar matter, stars: evolution, stars: individual: L-2 Puppis
National Category
Astronomy, Astrophysics and Cosmology
URN: urn:nbn:se:uu:diva-251976DOI: 10.1051/0004-6361/201322828ISI: 000351877600046OAI: oai:DiVA.org:uu-251976DiVA: diva2:812319

Correction in: Astronomy and Astrophysics, 2015, Volume: 581, Article Number: C2, DOI: 10.1051/0004-6361/201322828e

Available from: 2015-05-18 Created: 2015-04-28 Last updated: 2015-11-24Bibliographically approved

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