Related papers: Mz 3, a Multipolar Nebula in the Making
Stellar winds emitted by rotating massive stars may show two main components: firstly bipolar lobes with low density and fast wind, produced by the higher T$_{\mathrm{eff}}$ and gravity at the poles (`g$_{\mathrm{eff}}$-effect'); secondly,…
We conduct three-dimensional hydrodynamical simulations of two opposite jets launched obliquely to the orbital plane around an asymptotic giant branch (AGB) star and within its dense wind, and demonstrate the formation of a `messy'…
Planetary nebulae (PNe) can be roughly categorized into several broad morphological classes. The high quality images of PNe acquired in recent years, however, have revealed a wealth of fine structures that preclude simplistic models for…
Magnetic fields can play a major role in the dynamics of outstanding explosions associated to violent events such as GRBs and hypernovae, since they provide a natural mechanism to harness the rotational energy of the central proto-neutron…
Previous studies have explained the shapes of LBV nebulae, such as eta Car, by invoking the interaction of an isotropic fast wind with a previously deposited, slow aspherical wind (a "slow torus"). In this work I focus on the opposite…
We present 2D hydrodynamical simulations of the transition of a proto-planetary nebula to a planetary nebula for central stars in binary systems that have undergone a common envelope event. After 1,000 yr of magnetically driven dynamics…
We report the discovery of a bipolar nebula around the peculiar emission-line star MWC 349A using archival Spitzer Space Telescope 24 um data. The nebula extends over several arcminutes (up to 5 pc) and has the same orientation and geometry…
Of the known pulsar wind nebulae, 8 are good candidates for being in the early stage of evolution where the wind nebula is interacting with the freely expanding supernova ejecta. Several of these have been identified with historical…
Narrow-band H$\alpha$ and [N {\sc ii}] images and high-dispersion spatially-resolved echelle spectroscopy of the planetary nebula NGC 6891 are presented. These observations show a great wealth of structures. The bright central nebula is…
We show that the inclination to the line of sight of bipolar nebulae strongly affects some of their observed properties. We model these objects as having a spherically symmetric Planetary Nebula and a dusty equatorial density enhancement…
We conduct numerical simulations of axisymmetrical jets expanding into a spherical AGB slow wind. The three-dimensional flow is simulated with an axially symmetric numerical code. We concentrate on jets that are active for a relatively…
We present Submillimeter Array (SMA) mapping of $^{12}$CO $J=2\rightarrow 1$, $^{13}$CO $J=2\rightarrow 1$, and CN $N=2\rightarrow 1$ emission from the Ring-like planetary nebula (PN) NGC 3132, one of the subjects of JWST Early Release…
K3-35 is an extremely young bipolar planetary nebula that contains a precessing bipolar jet and a small (radius 80 AU) water maser equatorial ring. We have obtained VISIR- VLT images of K 3-35 in the PAH1 ({\lambda}=8.6 {\mu}m), [S iv]…
The young supernova remnant SNR 0540-69.3 in the Large Magellanic Cloud offers a detailed view of an energetic pulsar-wind nebula interacting with the surrounding ejecta. We present infrared observations of the central region of SNR…
We present results of our search for collimated ionized winds in bipolar nebulae using the Very Large Array (VLA) and the Australia Telescope Compact Array (ATCA). Our search is motivated by the discovery of an ionized jet in the bipolar…
We discuss the formation of planetary nebulae (PNe) having a pair of lobes, or multi-lobes, in their inner region surrounded by an elliptical or spherical shell or halo. We suggest that most of these PNe are formed by wide binary systems,…
Recent observations of the Egg Nebula (AFGL 2688), obtained at ever-increasing spatial and spectral resolution, have revealed a perplexing array of phenomena. Many of these phenomena present challenges to our understanding of this object as…
We present the result of a study on the expansion properties and internal kinematics of round/elliptical planetary nebulae of the Milky Way disk, the halo, and of the globular cluster M15. The purpose of this study is to considerably…
(Abridged) In the binary radio pulsar system J0737-3039, the faster pulsar A is eclipsed once per orbit. We construct a simple geometric model which successfully reproduces the eclipse light curves, based on the idea that the radio pulses…
The H2 and optical (Ha, [NII]) morphology of NGC 6881 are very different. Here we present a preliminary report of the analysis of new optical (Ha and [NII]) and near-IR (Brg and H2) images and intermediate resolution JHK spectra of this…