Results 41 to 50 of about 53,151 (238)
Chemical Synthesis in the Circumstellar Environment
GalaxiesWe discuss the spectral distinctions between B[e] stars and compact planetary nebulae. The differentiation between proto-planetary nebulae, transition objects between the asymptotic giant branch and planetary nebulae, and reflection nebulae in binary ...
Sun Kwok
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Planetary nebulae in M32 and the bulge of M31: Line intensities and oxygen abundances [PDF]
, 1998 We present spectroscopy of planetary nebulae in M32 and in the bulge of M31 that we obtained with the MOS spectrograph at the Canada-France-Hawaii Telescope. Our sample includes 30 planetary nebulae in M31 and 9 planetary nebulae in M32. We also observed one H II region in the disk of M31. We detected [O III]$\lambda$4363 in 18 of the planetary nebulae,
arxiv +1 more source
Вісник Астрономічної школи, 2003 270 photo ionization models of planetary nebulae luminescence was calculated. Free parameters for the models grid were energy distribution at the wavelengths 6912˚A, filling factor and chemical composition.
N. V. Gavrilova
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Mining of the Milky Way Star Archive Gaia-DR2. Searching for Binary Stars in Planetary Nebulae
Proceedings, 2020 The aim of this work is to search for binary stars associated to planetary nebulae (ionized stellar envelopes in expansion), by mining the astronomical archive of Gaia DR2, that is composed by around 1.7 billion stellar sources.
Iker González-Santamaría +4 more
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New and Misclassified Planetary Nebulae [PDF]
Symposium - International Astronomical Union, 1978 This fourth supplementary list to the CGPN (Perek, Kohoutek, 1967) contains 81 new objects (Table 1) which were published mainly between 1987 and 1990. We did not include as new PN those objects, which are in a transition phase between AGB and PN (no emission lines), and possible post-PN namely objects having central stars on the evolutionary way to WD
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Analysis of Multiple Shell Planetary Nebulae Based on HST/WFPC2 Extended 2D Diagnostic Diagrams
Galaxies, 2018 The investigation of gaseous nebulae, emitting in forbidden lines, is often based extensively on diagnostic diagrams. The special physics of these lines often allows for disentangling with a few line ratios normally coupled thermodynamic parameters like ...
Daniela Barría, Stefan Kimeswenger
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The Search for Binaries in Post-Asymptotic Giant Branch Stars: Do Binary Companions Shape the Nebulae? [PDF]
Journal of Astronomy and Space Sciences, 2012 Binary companions are often invoked to explain the axial and point symmetry seen in the majority of planetary nebulae and proto-planetary nebulae (PPNs).
Bruce J. Hrivnak
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Planetary Nebulae Populations in External Galaxies [PDF]
, 2011 This review highlights the properties of the planetary nebulae in external galaxies as tracers of light, of the stellar population properties, and of the distances and kinematics of the parent galaxies. Recent results on the kinematics of the outer regions in giant elliptical galaxies and on the luminosity specific PN numbers (the \alpha\ parameter) in
arxiv +1 more source
Symposium - International Astronomical Union, 1997 We review the properties of proto-planetary nebulae, highlighting the advances in our quantitative knowledge of these objects. The discussion focuses on the chemistry and morphology of their circumstellar envelopes and the chemistry and variability of their central stars.
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Planetary Nebulae Formation [PDF]
Highlights of Astronomy, 1980 It is a well accepted idea that Planetary Nebulae ( P.N. ) formation is due to mass ejection from red giant envelopes.According to the original model, as was proposed by Roxburgh and Lucy in 1967, and established about a year later by Paczynski and Ziolkowski (1968), red giant envelopes become dynamically unstable above a certain boundary luminosity ...
Z. Barkat, Y. Tuchman, N. Sack
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