Related papers: Bipolar outflows in OH/IR stars
The AGB star $\pi^{1}$ Gruis has a known companion (at a separation of ~400 AU) which cannot explain the strong deviations from the spherical symmetry of the CSE. Recently, hydrodynamic simulations of mass transfer in closer binary systems…
A CO\,2-1 line survey is performed toward a sample of 58 high Galactic latitude post-AGB (pAGB) stars. To complement the observations, a compilation of literature CO\,2-1 line data of known pAGB stars is done. After combining the datasets,…
The evolution of central stars of planetary nebulae can proceed in several distinct ways, either leading to H-deficiency or to H-normal surface composition. Several new simulations of the evolution channels that lead to H-deficiency are now…
Hot (OB) post-AGB stars are immediate progenitors of planetary nebulae (PNe). Very few hot post-AGB stars are known. Detecting new hot post-AGB candidates and follow-up multiwavelength studies will enable us to further understand the…
The rate of stellar evolution can rarely be measured in real time. The fastest evolution (excluding event-driven evolution), where stars may evolve measurably over decades, is during the post-AGB phase. In this paper we provide direct…
We report the results of an exploratory program to image the extended circumstellar envelopes of asymptotic giant branch (AGB) stars in dust-scattered galactic light. The goal is to characterize the morphology of the envelopes as a probe of…
To search for and study the instabilities in the atmospheres of selected post-AGB stars, we have performed a long-term high-resolution spectroscopy (R=60000) with the spectrograph NES of the 6-meter BTA telescope. Low-amplitude pulsations,…
We present first preliminary results from AKARI/FIS pointed observations of post-AGB stars and planetary nebulae (PNe). A first analysis of the radial (azimuthally averaged) profile of the observed sources shows no evidence for excess…
Intermediate mass stars (1-8 solar masses) evolve along the Asymptotic Giant Branch after completion of hydrogen and helium core burning. At the tip they lose for several ten to hundred thousand years copious amounts of mass and exhibit…
We present constraints on the molecular outflows in a sample of five Hyper-Luminous Infrared Galaxies using Herschel observations of the OH doublet at 119 {\mu}m. We have detected the OH doublet in three cases: one purely in emission and…
Massive molecular outflows erupting from high-mass young stellar objects provide important clues to understanding the mechanism of high-mass star formation. Based on new CO J=3-2 and J=1-0 observations using the Atacama Submillimeter…
We reproduce the expansion velocity--radius ($V_{\rm{exp}}$--$R_{\rm{n}}$) relation in planetary nebulae by considering a simple dynamical model, in order to investigate the dynamical evolution and formation of planetary nebulae. In our…
Stars of intermediate mass (~4-8Msun) evolve to the stage of white dwarfs through the asymptotic giant branch (AGB) stage: stationary hydrogen shell burning and helium thermal pulses, wind mass loss and planetary nebula ejection. Almost the…
Asymmetric 3D structures are observed in the outflows of evolved low- and intermediate-mass stars, and are believed to be shaped through the interaction of companions that are hidden within the dense wind. We investigate how triple systems…
The post-asymptotic giant branch (AGB) phase is arguably one of the least understood phases of the evolution of low- and intermediate- mass stars. The recent post-AGB evolutionary sequences computed by Miller Bertolami (2016) are at least…
We present molecular line, H2O maser, radio continuum and near infrared maps of the bipolar outflow source AFGL5142. The high resolution of our molecular CO observations enables us to define the morphology of the large-scale bipolar outflow…
There is gathering indirect evidence suggesting non-conservative evolutions in Algols. However, the systemic mass-loss rate is poorly constrained by observations and generally set as a free parameter in binary-star evolution simulations.…
Stars with masses between roughly 1 and 8~$M_\odot$ end their lives on the asymptotic giant branch (AGB), when intense mass loss takes place. The outflows are generally accepted to be driven by radiation pressure acting on dust grains that…
We present new deep imaging and high-resolution spectroscopy of the extreme-abundance-discrepancy planetary nebula Ou 5, together with photoionization modelling aimed at probing its unusual thermal and chemical structure. The nebula…
I study some effects of aspherical mass loss during the last stages of the asymptotic giant branch (AGB) on the appearance of proto planetary nebulae (PNs) and young PNs. The aspherical mass loss can be small scale inhomogeneities, and/or…