Related papers: Clumpy Flows in Protoplanetary and Planetary Nebul…
We present numerically calculated, disk--integrated, spectropolarimetric signals of starlight that is reflected by vertically and horizontally inhomogeneous gaseous exoplanets. We include various spatial features that are present on Solar…
The morphologies of planetary nebulae are believed to be self-organized configurations. These configurations are modeled by three-dimensional temporally self-similar magnetohydrodynamic solutions with radial flow, under the gravitational…
We consider the gravitational clustering of a multicomponent fluid in an expanding Newtonian universe, taking into account the mutual gravitational interactions of the medium. We obtain a set of exact and approximate solutions for two fluid…
A review of recent observations of the kinematics of six objects that represent the broad range of phenomena called planetary nebulae (PNe) is presented. It is demonstrated that Hubble-type outflows are predominant, consequently it is…
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…
We present new, third-epoch HST H-alpha and [S II] images of three HH jets (HH 1 and 2, HH 34, and HH 47) and compare these images with those from the previous epochs. The high-spatial resolution, coupled with a time-series whose cadence is…
We observed two proto-planetary nebulae, HD 56126 representing a source with an elliptical circumstellar shell and IRAS 16594-4656 representing a source with a bipolar circumstellar shell, with ALMA in the 12CO and 13CO J=3-2 lines and…
We present 3D hydrodynamical simulations of a jet launched from the secondary star of a binary system inside a proto-planetary nebula. The secondary star moves around the primary in a close eccentric orbit. From the gasdynamic simulations…
The evolution of a class of inhomogeneous spherically symmetric universe models possessing a varying cosmological term and a material fluid, with an adiabatic index either constant or not, is studied.
A recent paper [CGT] studies the evolution of star-shaped mean convex hypersurfaces of the Euclidean space by a class of nonhomogeneous expanding curvature flows. In the present paper we consider the same problem in the real, complex and…
This review describes some general properites of proto-planetary nebulae with particular emphasis on the recent work of morpholgical studies. The weight of observational evidence shows that proto-planetary nebulae (PPNe) are most certainly…
We present narrow-band H-alpha, [S II], and [O I] Hubble Space Telescope images of the young planetary nebula GL 618. This object is a compact, bipolar nebula that is currently undergoing the transition from asymptotic giant branch star to…
We report high spatial (0.5 arcsec) and high spectral (9 km/s) resolution spectro-imaging of the 2.12 micron H2 1-0 S(1) line in the proto-planetary nebula AFGL 618 using BEAR at the CFHT. The observations reveal the presence of multiple,…
We present chemical abundances for planetary nebulae and H II regions in the Local Group dwarf irregular galaxy NGC 6822 based upon spectroscopy obtained at the Canada-France-Hawaii Telescope using the Multi-Object Spectrograph. From these…
Many astrophysical flows occur in inhomogeneous media. The broad-line regions (BLR) of active galactic nuclei (AGNs) are one of the important examples where emission-line clouds interact with the outflow. We present results of a numerical…
Since various structural components of planetary nebulae manifest themselves differently, a combination of optical, infrared, submm, and radio techniques is needed to derive a complete picture of planetary nebulae. The effects of projection…
We compare abundances patterns in the Bulge for elements observed in stars and in planetary nebulae. Some alpha elements, like Mg and Ti, are overabundant respect to Fe, and others are not, like He, O, Si, S, Ar, Ca. The first ones favor a…
Fluid turbulence is commonly associated with stronger drag, greater heat transfer, and more efficient mixing than in laminar flows. In many natural and industrial settings, turbulent liquid flows contain suspensions of dispersed bubbles and…
High-mass gamma-ray binaries are powerful nonthermal galactic sources, some of them hosting a pulsar whose relativistic wind interacts with a likely inhomogeneous stellar wind. So far, modeling these sources including stellar wind…
In this work, a review is given of some recent results and problems involved in the determination of chemical abundances of galactic planetary nebulae, particularly regarding disk and bulge objects.