The circumstellar water fountains of IRAS 16342-3814 - A very high velocity bipolar outflow

Likkel, L.; Morris, Mark

doi:10.1086/166435

Cited by 57 publications

(60 citation statements)

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“…The velocities of OH masers at 1612, 1665, and 1667 MHz are ∼65 km s −1 , which are much faster than those in many OH/IR stars (Likkel & Morris 1988). The H 2 O masers are even faster ∼130−180 km s −1 (Zuckerman & Lo 1987;Likkel & Morris 1988). The apparent dynamical ages of the masers are very short at < ∼ 100 yr (Claussen et al 2009;Imai et al 2012).…”

Section: Introductionmentioning

confidence: 97%

“…Another characteristic of this object is high-velocity maser components. The velocities of OH masers at 1612, 1665, and 1667 MHz are ∼65 km s −1 , which are much faster than those in many OH/IR stars (Likkel & Morris 1988). The H 2 O masers are even faster ∼130−180 km s −1 (Zuckerman & Lo 1987;Likkel & Morris 1988).…”

Section: Introductionmentioning

confidence: 99%

“…The H 2 O masers are more like jets in appearance than the typical AGB winds. Because of these maser properties, objects like I16342 are called "water fountain source (WFS)" (Likkel & Morris 1988;Imai et al 2007). So far, 14 objects are classified into this group (Imai et al 2007;Suárez et al 2009;Walsh et al 2009;Gómez et al 2011).…”

Section: Introductionmentioning

confidence: 99%

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Dust shell model of the water fountain source IRAS 16342–3814

Murakawa

Izumiura²

2012

A&A

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Aims. We investigate the circumstellar dust shell of the water fountain source IRAS 16342-3814. Methods. We performed two-dimensional radiative transfer modeling of the dust shell, taking into account previously observed spectral energy distributions (SEDs) and our new J-band imaging and H-and K S -band imaging polarimetry obtained using the VLT/NACO instrument. Results. Previous observations expect an optically thick torus in the equatorial plane because of a striking bipolar appearance and a large viewing angle of 30−40 • . However, models with such a torus as well as a bipolar lobe and an AGB shell cannot fit the SED and the images simultaneously. We find that an additional optically and geometrically thick disk located inside a massive torus solves this problem. The masses of the disk and the torus are estimated to be 0.01 M at the a max = 100 μm dust and 1 M at a max = 10 μm dust, respectively. Conclusions. We discuss a possible formation scenario for the disk and torus based on a similar mechanism to the equatorial back flow. IRAS 16342-3814 is expected to undergo mass loss at a high rate. The radiation from the central star is shielded by the dust that was ejected in the subsequent mass loss event. As a result, the radiation pressure on dust particles cannot govern the motion of the particles anymore. The mass loss flow can be concentrated in the equatorial plane by help of an interaction, which might be the gravitational attraction by the companion, if it exists in IRAS 16342-3814. A fraction of the ejecta is captured in a circum-companion or circum-binary disk and the remains are escaping from the central star(s) and form the massive torus.

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Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

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Dust shell model of the water fountain source IRAS 16342–3814

Murakawa

Izumiura²

2012

A&A

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“…The first WF nebulae was reported by Likkel & Morris (1988). Results from interferometric observations towards the circumstellar envelopes (CSE) of WFs indicate that, in most cases, the spatial distribution of the detected H 2 O maser components (projected on the plane of the sky) can be correlated with large-scale bipolar structures (e.g.…”

Section: Introductionmentioning

confidence: 99%

Deep into the Water Fountains

Pérez-Sánchez

Tafoya

López

et al. 2017

A&A

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Context. The formation of large-scale (hundreds to few thousands of AU) bipolar structures in the circumstellar envelopes (CSEs) of post-Asymptotic Giant Branch (post-AGB) stars is poorly understood. The shape of these structures, traced by emission from fast molecular outflows, suggests that the dynamics at the innermost regions of these CSEs does not depend only on the energy of the radiation field of the central star. Aims. Multi-frequency observations towards a group of post-AGB sources known as Water Fountain nebulae can help to constrain the nature of the mechanism responsible for the launching and collimation of the fast molecular outlflows traced by high-velocity features of H 2 O maser emission. Methods. Deep into the Water Fountains is an observational project based on the results of programs carried out with three telescope facilities: The Karl G. Jansky Very Large Array (JVLA), The Australia Telescope Compact Array (ATCA), and the Very Large Telescope (SINFONI-VLT). Results. Here we report the results of the observations towards the WF nebula IRAS 18043−2116: Detection of radio continuum emission in the frequency range 1.5 GHz -8.0 GHz; H 2 O maser spectral features and radio continuum emission detected at 22 GHz, and H 2 ro-vibrational emission lines detected at the near infrared. Conclusions. The high-velocity H 2 O maser spectral features, and the shock-excited H 2 emission detected could be produced in molecular layers which are swept up as a consequence of the propagation of a jet-driven wind. Using the derived H 2 column density, we estimated a molecular mass-loss rate of the order of 10 −9 M yr −1 . On the other hand, if the radio continuum flux detected is generated as a consequence of the propagation of a thermal radio jet, the mass-loss rate associated to the outflowing ionized material is of the order of 10 −5 M yr −1 . The presence of a rotating disk could be a plausible explanation for the mass-loss rates estimated.

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“…This outflow source was first discovered by Likkel & Morris (1988) and te Lintel Hekkert et al (1988), and shows both OH and H2O outflows. The highly variable H2O masers occur in pairs at opposite velocity, at a number of discrete velocities (Likkel, Morris & Maddalena 1992).…”

Section: Iras 16342−3814mentioning

confidence: 57%

Bipolar Outflows from OH/IR Stars

Zijlstra

2001

Post-Agb Objects as a Phase of Stellar Evolution

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We investigate the development of bipolar outflows during the early post-AGB evolution. A sample of ten OH/IR stars with irregular OH spectra and unusually large expansion velocities is observed at high angular resolution. The sample includes bipolar nebulae (e.g. OH231.8+4.2), bright post-AGB stars (HD 101584) and reflection nebulae (e.g. Roberts 22). The IRAS colour-colour diagram separates the sample into different types of objects. One group may contain the immediate progenitors to the (few) extreme bipolar planetary nebulae. Two objects show colours and chemistry very similar to the planetary nebulae with late IR-[WC] stars. One object is a confirmed close binary.A model is presented consisting of an outer AGB wind which is swept up by a faster post-AGB wind, with either the AGB or Post-AGB wind being non-spherically symetric. The interface of the two winds is shown to exhibit a linear relation between velocity and distance from the star, giving the impression of an accelerating outflow. The OH data confirms the predicted linear velocity gradients, and also reveals toruslike, uniformly expanding components.All sources are discussed in detail using optical/HST images where available. ISO data for Roberts 22 reveal a chemical dichotomy, with both crystalline silicates and PAHs features being present. IRAS 16342−3814 shows a dense torus with mass 0.1 M ⊙ and density of 10 8 cm −3 ; HST data shows four point-like sources located symmetrically around the nebula, near the outer edge of the dense torus.Lifetimes for the bipolar OH/IR stars are shown to be in excess of 10 4 yr, longer than normal post-AGB timescales. This suggests that the toruses or disks are nearstationary. We suggest that accretion from such a disk slows down the post-AGB evolution. Such a process could explain the link between the long-lived bipolar nebular geometry and the retarded star.

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The circumstellar water fountains of IRAS 16342-3814 - A very high velocity bipolar outflow

Cited by 57 publications

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Dust shell model of the water fountain source IRAS 16342–3814

Dust shell model of the water fountain source IRAS 16342–3814

Deep into the Water Fountains

Bipolar Outflows from OH/IR Stars

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