Related papers: The nebula around the binary post-AGB star 89 Herc…

Aims. In this study, we determine the morphology and mass-loss rate of jets emanating from the companion in post-asymptotic giant branch (post-AGB) binary stars with a circumbinary disk. In doing so, we also determine the mass accretion…

Symbiotic systems often include an asymptotic giant branch (AGB) star and a hot compact companion, such as a white dwarf, that are in close interaction. Due to the intense ultraviolet emission from the hot companion, the molecular content…

We examine the flow from asymptotic giant branch (AGB) stars when along a small solid angle the optical depth due to dust is very large. We consider two types of flows. In the first, small cool spots are formed on the surface of slowly…

Aims: We aim to characterize the physical and morphological properties of the binary system AFGL 4106, composed of two evolved massive stars. Understanding its mass-loss processes and circumstellar environment offers insight into the late…

We have obtained deep optical spectrophotometry of 16 planetary nebulae in M33, mostly located in the central two kpc of the galaxy, with the Subaru and Keck telescopes. We have derived electron temperatures and chemical abundances from the…

Several classes of stellar binaries with post-main sequence (post-MS) components - millisecond pulsars with the white dwarf companions (MSP+WD) and periods P_b~30 d, binaries hosting post-asymptotic giant branch (post-AGB) stars or barium…

Hydrogen-deficient central stars of planetary nebula such as Wolf-Rayet and PG1159 central stars and some weak emission line stars are primarily composed of helium and carbon. This abundance is well explained by a scenario where a single…

We present mid-infrared Spitzer spectra of eleven planetary nebulae in the Galactic Bulge. We derive argon, neon, sulfur, and oxygen abundances for them using mainly infrared line fluxes combined with some optical line fluxes from the…

A super-solar fluorine abundance was observed in the carbon-enhanced metal-poor (CEMP) star HE 1305+0132 ([F/Fe] = +2.90, [Fe/H] = -2.5). We propose that this observation can be explained using a binary model that involve mass transfer from…

We have done a detailed abundance analysis of four unexplored candidate post- Asymptotic Giant Branch(AGB) stars IRAS 13110 - 6629, IRAS 17579 - 3121, IRAS 18321 - 1401 and IRAS 18489 - 0629 using high resolution spectra. We have…

The observations and comprehensive study of intermediate initial mass stars at the late stages of evolution, and after the asymptotic giant branch (AGB) in particular, are of crucial importance to identify the common properties for the…

Studying the appearance and properties of bipolar winds is critical to understand the stellar evolution from the AGB to the planetary nebula (PN) phase. Many uncertainties exist regarding the presence and role of binary stellar systems,…

Maser lines of OH, H2 O, and SiO are commonly observed in O-rich AGB stars, but their presence after the end of the Asymptotic Giant Branch (AGB) phase is linked to non-spherical mass-loss processes. IRAS 15452-5459 is a post-AGB star with…

The discrepancy between abundances computed using optical recombination lines (ORLs) and collisionally excited lines (CELs) is a major unresolved problem in nebular astrophysics. We show here that the largest abundance discrepancies are…

The CO(1-0) and (2-1) emission of the circumstellar envelope of the AGB star EP Aqr has been observed using the IRAM PdBI and the IRAM 30-m telescope. The line profiles reveal the presence of two distinct components centered on the star…

We present new binary stellar evolution models that include the effects of tidal forces, rotation, and magnetic torques with the goal of testing Planetary Nebulae (PNe) shaping via binary interaction. We explore whether tidal interaction…

Asymmetric shapes and evidence for binary central stars suggest a common-envelope origin for many bipolar planetary nebulae. The bipolar components of the nebulae are observed to expand faster than the rest and the more slowly expanding…

We report interferometric mapping of the bipolar pre-planetary nebula IRAS 08005-2356 with an angular-resolution of ~1"-5", using the Submillimeter Array (SMA), in the 12CO J=2-1, 3-2, 13CO J=2-1 and SiO J=5-4 (v=0) lines. Single-dish…

Post-asymptotic giant branch (post-AGB) binary stars are evolved systems that host circumbinary discs formed through mass loss during late stage binary interactions. Their structural, morphological, kinematic, and chemical similarities to…

We present an evolutionary sequence of a low mass star from the Asymptotic Giant Branch (AGB) through its post-AGB stage, during which its surface chemical composition changes from hydrogen-rich to strongly hydrogen-deficient as consequence…