The detached dust shells of AQ Andromedae, U Antliae, and TT Cygni

Kerschbaum, F.; Ladjal, D.; Ottensamer, R.; Groenewegen, M. A. T.; Mečina, M.; Blommaert, J. A. D. L.; Baumann, Bernhard; Decin, L.; Vandenbussche, B.; Waelkens, C.; Posch, Th.; Huygen, E.; Meester, W. De; Regibo, S.; Royer, P.; Exter, Katrina; Jean, C.

doi:10.1051/0004-6361/201014633

Cited by 41 publications

(59 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Both targets show spherically symmetric detached circumstellar emission, as is similarly seen around the stars presented in Kerschbaum et al (2010). The circumstellar environment of S Sct is rather well studied, especially in CO line emission.…”

Section: Introductionsupporting

confidence: 62%

Dusty shells surrounding the carbon variables S Scuti and RT Capricorni

Mečina

Kerschbaum

Groenewegen

et al. 2014

A&A

Self Cite

View full text Add to dashboard Cite

For the Mass-loss of Evolved StarS (MESS) programme, the unprecedented spatial resolution of the PACS photometer on board the Herschel Space Observatory was employed to map the dusty environments of asymptotic giant branch (AGB) and red supergiant (RSG) stars. Among the morphologically heterogeneous sample, a small fraction of targets is enclosed by spherically symmetric detached envelopes. Based on observations in the 70 μm and 160 μm wavelength bands, we investigated the surroundings of the two carbon semiregular variables S Sct and RT Cap, which both show evidence for a history of highly variable mass-loss. S Sct exhibits a bright, spherically symmetric detached shell, 138 in diameter and co-spatial with an already known CO structure. Moreover, weak emission is detected at the outskirts, where the morphology seems indicative of a mild shaping by interaction of the wind with the interstellar medium, which is also supported by the stellar space motion. Two shells are found around RT Cap that were not known so far in either dust emission or from molecular line observations. The inner shell with a diameter of 188 shows an almost immaculate spherical symmetry, while the outer ∼5 structure is more irregularly shaped. MoD, a modification of the DUSTY radiative transfer code, was used to model the detached shells. Dust temperatures, shell dust masses, and mass-loss rates are derived for both targets.

show abstract

Section: Introductionsupporting

confidence: 62%

Dusty shells surrounding the carbon variables S Scuti and RT Capricorni

Mečina

Kerschbaum

Groenewegen

et al. 2014

A&A

Self Cite

View full text Add to dashboard Cite

show abstract

“…We note here that some stars with prominent dust shells, e.g. AX Cyg and RT Cap (Kerschbaum et al 2010;Mečina et al 2014), do not have detectable CO shells, most likely an effect of CO photodissociation if the shell is old enough. Even though most of the mass is not lost during these episodes, they provide an interesting phenomenon which may shed light on the mass-loss mechanism of AGB stars, e.g.…”

Section: Introductionmentioning

confidence: 77%

“…The shell ejection time scale is a few hundred years (Olofsson et al 2000;Maercker et al 2012). Curiously, no M-stars, which also go through thermal pulsing, have been found with detached CO and/or dust shells of this type despite several searches (Nyman et al 1992;Kerschbaum & Olofsson 1999;Kerschbaum et al 2010).…”

Section: Introductionmentioning

confidence: 99%

Detection of CI line emission from the detached CO shell of the AGB star R Sculptoris

Olofsson

Bergman

Lindqvist

2015

A&A

View full text Add to dashboard Cite

Context. Stars on the asymptotic giant branch (AGB) lose substantial amounts of matter, to the extent that they are important for the chemical evolution of, and dust production in, the Universe. The mass loss is believed to increase gradually with age on the AGB, but it may also occur in the form of bursts, possibly related to the thermal pulsing phenomenon. Detached, geometrically thin, CO shells around carbon stars are good signposts of brief and intense mass ejection. Aims. We aim to put further constraints on the physical properties of detached CO shells around AGB stars. Methods. The photodissociation of CO and other carbon-bearing species in the shells leads to the possibility of detecting lines from neutral carbon. We have therefore searched for the CI( 3 P 1 − 3 P 0 ) line at 492 GHz towards two carbon stars, S Sct and R Scl, with detached CO shells of different ages, ≈8000 and 2300 years, respectively. Results. The CI( 3 P 1 − 3 P 0 ) line was detected towards R Scl. The line intensity is dominated by emission from the detached shell. The detection is at a level consistent with the neutral carbon coming from the full photodissociation of all species except CO, and with only limited photoionisation of carbon. The best fit to the observed 12 CO and 13 CO line intensities, assuming a homogeneous shell, is obtained for a shell mass of ≈0.002 M , a temperature of ≈100 K, and a CO abundance with respect to H 2 of 10 −3 . The estimated CI/CO abundance ratio is ≈0.3 for the best-fit model. However, a number of arguments point in the direction of a clumpy medium, and a viable interpretation of the data within such a context is provided.

show abstract

“…AGB stars experience thermal pulses (TPs) during which intense mass loss ejections occur. A star can undergo several TPs, which would lead to the formation of concentric spherical detached shells (see Kerschbaum et al 2010).…”

Section: Bow Shock Thermal Pulse or Both?mentioning

confidence: 99%

HerschelPACS and SPIRE imaging of CW Leonis

Ladjal¹,

Barlow

Groenewegen

et al. 2010

A&A

Self Cite

View full text Add to dashboard Cite

Herschel PACS and SPIRE images have been obtained over a 30 × 30 area around the well-known carbon star CW Leo (IRC +10 216). An extended structure is found in an incomplete arc of ∼22 diameter, which is cospatial with the termination shock due to interaction with the interstellar medium (ISM) as defined by Sahai & Chronopoulos from ultraviolet GALEX images. Fluxes are derived in the 70, 160, 250, 350, and 550 μm bands in the region where the interaction with the ISM takes place, and this can be fitted with a modified black body with a temperature of 25 ± 3 K. Using the published proper motion and radial velocity for the star, we derive a heliocentric space motion of 25.1 km s −1 . Using the PACS and SPIRE data and the analytical formula of the bow shock structure, we infer a de-projected standoff distance of the bow shock of R 0 = (8.0 ± 0.3) × 10 17 cm. We also derive a relative velocity of the star with respect to the ISM of (106.6 ± 8.7)/ √ n ISM km s −1 , where n ISM is the number density of the local ISM.

show abstract

The detached dust shells of AQ Andromedae, U Antliae, and TT Cygni

Cited by 41 publications

References 25 publications

Dusty shells surrounding the carbon variables S Scuti and RT Capricorni

Dusty shells surrounding the carbon variables S Scuti and RT Capricorni

Detection of CI line emission from the detached CO shell of the AGB star R Sculptoris

HerschelPACS and SPIRE imaging of CW Leonis

Contact Info

Product

Resources

About