Dissecting the AGB star L2 Puppis: a torus in the making

Abstract

The circumstellar environment of L2 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. 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 $\mu \mathrm{m}$) on the NACO/VLT, both in imaging and polarimetric modes. The aperture-masking images of L2 Pup at 2.30 $\mu \mathrm{m}$ show a resolved structure that resembles a toroidal structure with a major axis of ~140 milliarcseconds (mas) and an east-west orientation. Two clumps can be seen on either side of the star, ~65 mas from the star, beyond the edge of the circumstellar envelope (estimated diameter is ~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 $\mu \mathrm{m}$ 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 km s${}^{-1}$ as suggested by the SiO maser profile, we estimate a stellar mass of 0.7 M${}_{\odot }$.}

9 pages, 7 figures, to be published in A&A

References in corpus (6)

• A close halo of large transparent grains around extreme red giant stars
• Imaging the circumstellar envelopes of AGB stars
• The Mira variable S Ori: Relationships between the photosphere, molecular layer, dust shell, and SiO maser shell at 4 epochs
• Pre-maximum spectro-imaging of the Mira star T Lep with AMBER/VLTI
• Inhomogeneities in molecular layers of Mira atmospheres
• An edge-on translucent dust disk around the nearest AGB star L2 Puppis - VLT/NACO spectro-imaging from 1.04 to 4.05 microns and VLTI interferometry

Cited by in corpus (5)

• Stellar and substellar companions from Gaia EDR3 -- Proper motion anomaly and resolved common proper motion pairs
• Fundamental parameters and infrared excesses of Tycho-Gaia stars
• ALMA observations of the nearby AGB star L2 Puppis - I. Mass of the central star and detection of a candidate planet
• Morpho-kinematics of the wind of AGB star L${}_2$ Pup
• Circumstellar CO J = 3-2 detected around the evolving metal-poor ([Fe/H] ~ -1.15 dex) AGB star RU Vulpeculae