Imaging the circumstellar dust around AGB stars with PolCor

Abstract

The aim of this paper is to investigate how the new imaging Polarimeter and Coronograph (PolCor) at the Nordic Optical Telescope (NOT) can be used in the study of circumstellar structures around AGB stars, with the purpose of preparing for a study of a larger sample. We have observed two types of AGB stars using the PolCor instrument on the NOT: the binary S-type star W Aql and two carbon stars with detached shells, U Cam and DR Ser. The polarized light traces the dust distribution around the stars. From the polarimeter images the polarized intensity, the polarization degree, and the polarization angle over the images are calculated. The location and extent of dust structures are examined in the images. The total dust mass and the dust-to-gas ratios of the detached shells are also calculated. The images of the circumstellar envelope of W Aql show what seems to be an elongated structure in the south-west direction. The detached shells of U Cam and DR Ser are clearly seen in the images. This is the first time the detached shell around DR Ser has been imaged. The radii and widths of the shells are determined and found to be 7.9" and 7.6", and 0.9" and 1.2", for U Cam and DR Ser, respectively. This is consistent with previous results. The dust masses of the feature south-west of W Aql, and in the shells of U Cam and DR Ser are also estimated and found to be 1x10^-6, 5x10^-7, and 2x10^-6 Msun, respectively. W Aql is a known binary and the shape of the circumstellar envelope seems to be in line with what could be expected from binary interaction on these scales. For the shells, the results are in agreement with previous investigations. Ages and formation time-scales are also estimated for the detached shells and found to be consistent with the thermal-pulse-formation scenario.

Accepted for publication in A&A

References in corpus (10)

• Evidence for the White Dwarf Nature of Mira B
• Low-Mass Binary Induced Outflows from Asymptotic Giant Branch Stars
• Too little radiation pressure on dust in the winds of oxygen-rich AGB stars
• Imaging the circumstellar envelopes of AGB stars
• Numerical Simulations of Wind Accretion in Symbiotic Binaries
• The circumstellar envelope of IRC+10216 from milli-arcsecond to arcmin scales
• The distribution of SiO in the circumstellar envelope around IRC+10216
• Discovery of an HI Counterpart to the Extended Tail of Mira
• Detection of `parent' molecules from the inner wind of AGB stars as tracers of non-equilibrium chemistry
• Infrared Spectroscopic Study of a Selection of AGB and Post-AGB Stars

Cited by in corpus (27)

• Sparkling nights and very hot days on WASP-18b: the formation of clouds and the emergence of an ionosphere
• Evolution and Mass Loss of Cool Ageing Stars: a Daedalean Story
• The 12CO/13CO ratio in AGB stars of different chemical type-Connection to the 12C/13C ratio and the evolution along the AGB
• Detailed modelling of the circumstellar molecular line emission of the S-type AGB star W Aquilae
• Large-scale environments of binary AGB stars probed by Herschel - I. Morphology statistics and case studies of R Aquarii and W Aquilae
• On the dust abundance gradients in late-type galaxies: I. Effects of destruction and growth of dust in the interstellar medium
• ATOMIUM: ALMA tracing the origins of molecules in dust forming oxygen rich M-type stars: Motivation, sample, calibration, and initial results
• A detailed view of the gas shell around R Sculptoris with ALMA
• The circumstellar envelope around the S-type AGB star W Aql Effects of an eccentric binary orbit
• ATOMIUM: Halide molecules around the S-type AGB star W Aquilae
• The detached dust shells around the carbon AGB stars R Scl and V644 Sco
• The VLT/SPHERE view of the ATOMIUM cool evolved star sample. I. Overview: Sample characterization through polarization analysis
• Molecular line study of the S-type AGB star W Aquilae. ALMA observations of CS, SiS, SiO and HCN
• Chemical tracers of a highly eccentric AGB-main sequence star binary
• Classifying the secondary component of the binary star W Aquilae
• Modeling rotational disruption of grains and microwave emission from spinning dust in AGB envelopes
• Dusty shells surrounding the carbon variables S Scuti and RT Capricorni
• Properties of dust in the detached shells around U Ant, DR Ser, and V644 Sco
• First Detection of UV emission from a Detached Dust Shell: GALEX Observations of the Carbon AGB Star U Hya
• Detection of CI line emission from the detached CO shell of the AGB star R Sculptoris
• The Nearby Evolved Stars Survey: I. JCMT/SCUBA-2 Sub-millimetre detection of the detached shell of U Antliae
• ATOMIUM: Continuum emission and evidence of dust enhancement from binary motion
• Polarimetric coronagraphy of BD+31643
• An independent distance estimate to the AGB star R Sculptoris
• Probing the dynamical and kinematical structures of detached shells around AGB stars
• Morphology and kinematics of the gas envelope of the Mira binary W Aquilae
• Detached Shell Carbon Stars: Tracing Thermal Pulses on the Asymptotic Giant Branch