相关论文: A Dust-Scattering Model for M1-92: A Revised Estim…
In 1992 the Far-Ultraviolet Space Telescope (FAUST) provided measurements of the ultraviolet (140-180nm) diffuse sky background at high, medium, and low Galactic latitudes. A significant fraction of the detected radiation was found to be of…
Planetary Nebulae represent a powerful window into the evolution of low-intermediate mass stars that have undergone extensive mass-loss. The nebula manifests itself in an extremely wide variety of shapes, but exactly how the mass lost is…
Binarity and mass transfer appear to play a key role in the shaping and, possibly, formation of planetary nebulae (PNe), thereby explaining the large fraction of axisymmetric morphologies. I present the binary hypothesis for PNe and its…
The abundance evolution of interstellar dust species originating from stellar sources and from condensation in molecular clouds in the local interstellar medium of the Milky Way is studied and the input of dust material to the Solar System…
A sample of 25 IR-bright planetary nebulae (PNe) towards the Galactic bulge is analysed through 8-13um spectroscopy. The classification of the warm-dust emission features provides a measure of the C/O chemical balance, and represents the…
The wavelength dependences of interstellar extinction and polarization, supplemented by observed elemental abundances and the spectrum of infrared emission from dust heated by starlight, strongly constrain dust models. One dust model that…
The central star of the planetary nebula (CSPN) M 2-29 shows an extraordinary R Coronae Borealis-like fading event in its optical lightcurve. The only other CSPN to show these events are CPD-568032 (Hen 3-1333) and V651 Mon (NGC 2346). Dust…
We present new low-resolution (R~800) optical spectra of 22 Galactic PNe with Spitzer spectra. These data are combined with recent optical spectroscopic data available in the literature to construct representative samples of compact (and…
The timescales to replenish dust from the cool, dense winds of Asymptotic Giant Branch stars are believed to be greater than the timescales for dust destruction. In high redshift galaxies, this problem is further compounded as the stars…
The shaping of the nebula is currently one of the outstanding unsolved problems in planetary nebula (PN) research. Several mechanisms have been proposed, most of which require a binary companion. However, direct evidence for a binary…
The decrease rate of dust mass due to strong shock waves ($v_s\geq 150$ km s$^{-1}$) from supernovae (SNe) estimated for the Milky Way interstellar medium significantly exceeds the overall production rate by both asymptotic giant branch…
Bipolarity in proto-planetary and planetary nebulae is associated with events occurring in or around their cores. Past infrared observations have revealed the presence of dusty structures around the cores, many in the form of disks.…
Late stages of stellar evolution are characterized by copious mass-loss events whose signature is the formation of circumstellar envelopes (CSE). Planck multi-frequency measurements have provided relevant information on a sample of Galactic…
We report a centimetre-wave (cm-wave, 5-31GHz) excess over free-free emission in PNe. Accurate 31 and 250GHz measurements show that the 31GHz flux densities in our sample are systematically higher than the level of optically thin free-free…
We present low and high resolution long-slit spectra of three bipolar planetary nebulae (PNe) with bright central cores: A79, He2-428 and M1-91. He2-428 and M1-91 have high density (from 10^3.3 to 10^6.5 cm^-3) unresolved nebular cores that…
We present various infrared two-color diagrams (2CDs) for AGB stars, post-AGB stars, and Planetary Nebulae (PNe) and investigate possible evolutionary tracks. We use catalogs from the available literature for the sample of 4903 AGB stars…
Planetary nebulae (PNe) shown to be members of star clusters provide information on their properties and evolutionary histories that cannot be determined for PNe in the field, in particular the initial masses of their progenitor stars. Here…
In supernovae (SNe), where the light curves show evidence of strong and early interaction between the ejecta and the circumstellar matter (CSM), the formation of new dust is estimated to take place in a dense shell of gas between the…
M2-9, or the "Butterfly Nebula" is one of the most iconic outflow sources from an evolved star. In this paper we present a hydrodynamic model of M2-9 in which the nebula is formed and shaped by a steady, low-density ("light"), mildly…
We present images and slitless spectra which were obtained in HST surveys of Planetary Nebulae (PNe) in both the Large and Small Magellanic Clouds, using the Space Telescope Imaging Spectrograph. These new data on 59 PNe (54 in the LMC and…