Do Thi Hoai

12CO emission from the Red Rectangle

Observations of an unprecedented quality made by ALMA on the Red Rectangle of CO(3–2) and CO(6–5) emissions are analysed jointly with the aim of obtaining as simple as possible a description of the gas morphology and kinematics. Evidence is found for polar conical outflows and for a broad equatorial torus in rotation and expansion. Simple models of both are proposed. Comparing CO(6–5) and CO(3–2) emissions provides evidence for a strong temperature enhancement over the polar outflows. Continuum emission (dust) is seen to be enhanced in the equatorial region. Observed asymmetries are briefly discussed.

The multi-scale environment of RS Cnc from CO and Hi observations ⋆

We present a detailed study of the circumstellar gas distrib ution and kinematics of the semi-regular variable star RS Cnc on spatial scales ranging from∼ 1 ′′ (∼150 AU) to∼ 6 ′ (∼0.25 pc). Our study utilizes new CO1-0 data from the Plateau-de-Bure Interferometer and new Hi 21-cm line observations from the Jansky Very Large Array (JVLA), in combination with previous observations. New modeling of CO1-0 and CO2-1 imaging observations leads to a revised characterization of RS Cnc’s previously identified a xisymmetric molecular outflow. Rather than a simple disk-outflow pict ure, we find that a gradient in velocity as a function of latitu de is needed to fit the spatially resolved spectra, and in our preferred mo del, the density and the velocity vary smoothly from the equatorial plane to the polar axis. In terms of density, the source appears quasi -spherical, whereas in terms of velocity the source is axi-s ymmetric with a low expansion velocity in the equatorial plane and faster outflows in the polar directions. The flux of matter is also large r in the polar directions than in the equatorial plane. An implication of o ur model is that the stellar wind is still accelerated at radi i larger than a few hundred AU, well beyond the radius where the terminal velocity is thought to be reached in an asymptotic giant branch star. The JVLA Hi data show the previously detected head-tail morphology, but also supply additional detail about the atomic gas distrib ution and kinematics. We confirm that the ‘head’ seen in H i is elongated in a direction consistent with the polar axis of the molecular outflow, suggesting that we are tracing an extension of the molecular outflow well beyond the molecular dissociation radius (up to ∼0.05 pc). The 6 ′ -long Hi ‘tail’ is oriented at a PA of 305 ◦ , consistent with the space motion of the star. The tail is res olved into several clumps that may result from hydrodynamic effects linked to the interaction with the local interstellar m edium. We measure a total mass of atomic hydrogen MHI≈ 0.0055M⊙ and estimate a lower limit to the timescale for the formation of the tail to be∼ 6.4× 10 4 years.

On the central symmetry of the circumstellar envelope of RS Cnc

We present a phenomenological study of CO(1-0) and CO(2-1) emission from the circumstellar envelope (CSE) of the Asymptotic Giant Branch (AGB) star RS\,Cnc. It reveals departures from central symmetry that turn out to be efficient tools for the exploration of some of the CSE properties. We use a wind model including a bipolar flow with a typical wind velocity of

Morphology and kinematics of the gas envelope of the Mira binary W Aquilae

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The Vatly Radio Telescope: Performance Study

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Mapping Atomic Hydrogen in the Disk of the Milky Way

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Morphology of the

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CO(3-2) millimeter emission across the gas disc surrounding the triple protostar GG Tau A using ALMA observations

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Morphology and kinematics of the gas envelope of the variable AGB star π^1 Gruis

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