Results 21 to 30 of about 335 (184)
Temperatures and Luminosities of Planetary Nebulae Nuclei [PDF]
Symposium - International Astronomical Union, 1989 The location of Planetary Nebulae Nuclei (PNNi) on the H-R diagram is a very important clue to understand the evolution of these objects.
Luciana Bianchi +2 more
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Radio sources in the Chandra Galactic Bulge Survey [PDF]
, 2012 We discuss radio sources in the Chandra Galactic Bulge Survey region. By cross-matching the X-ray sources in this field with the NRAO VLA Sky Survey archival data, we find 12 candidate matches.
Maccarone, M.C. +24 more
core +1 more source
Spectroscopic observations of nuclei of planetary nebulae [PDF]
Symposium - International Astronomical Union, 1984 Up to date, 1518 true, possible, and probable planetary nebulae (PN) are known in our Galaxy; 463 nuclei (NPN) were observed. For about 150 stars, a spectral study has been done; only about 30 NPN have a well studied spectrum. (Acker, Gleizes et al, 1982 “Catalogue of the central stars of true and possible PN”) It must be remembered that this is a ...
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CCD Images of Three Planetary Nebulae With Binary Nuclei [PDF]
Symposium - International Astronomical Union, 1989 A 14, H 3-75 and K 1-2, three planetary nebulae with binary nuclei, were imaged with narrow-band [N II], Ha, [O III] and He II filters by using the TI CCD chip on the 0.9-m telescope at CTIO. The purpose of doing the observing was to see if planetaries with known binary nuclei exhibit particularly peculiar morphologies.
Julie Lutz, Nancy Jo Lame
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Planetary Nebulae by Binary Nuclei [PDF]
Symposium - International Astronomical Union, 1993 Planetary nebulae with close binary nuclei are reviewed. It is shown that these systems can be used as a source of information for the physics of the common envelope phase in the evolution of binary systems. Mechanisms for the production of bipolar planetary nebulae are examined and it is concluded that presently the action of binary companions to the ...
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Abell-35 Phenomena in Symbiotic Stars: Discovery of 1.2 and 6.4 Day Periods in VV8 (V471 Per)
Open Astronomy, 2012 We have collected high precision optical photometry of VV8, so far 782 individual observing runs uniformly distributed over the period 2005 - 2011. This dataset allows us to refine the known long periodicity of VV8 to P = 16.8 yr, with peak-to-valley ...
Munari U. +10 more
doaj +1 more source
Atoms, 2014 We review studies of two kinds of dips in spectral line profiles emitted by plasmas—dips that have been predicted theoretically and observed experimentally: Langmuir-wave-caused dips (L-dips) and charge-exchange-caused dips (X-dips). There is a principal
Elisabeth Dalimier +2 more
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Binary Nuclei of Planetary Nebulae [PDF]
Symposium - International Astronomical Union, 1978 In view of the spectral similarity and the probable evolutionary relation between certain planetary nebulae (PN) and other objects that are generally binaries (symbiotic stars, Be stars, or slow novae), it is probable that many nuclei of PN are double.
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Turbulent planetary nebulae around [WC]–type stars
, 2002 Through a high-resolution spectroscopic survey, we analyze the velocity field of 16 planetary nebulae with [WC]- or wels-type nuclei in comparison with 8 nebulae having other central star types.
Y. Grosdidier +3 more
core +1 more source
Models for Nuclei of Planetary Nebulae and for Ultraviolet Stars [PDF]
Symposium - International Astronomical Union, 1974 A series of stellar models were evolved, all with a total mass of 0.65 M⊙, an initial carbon-oxygen core of mass 0.60 M⊙, an intermediate helium mantle and an outer hydrogen-rich envelope with mass varying from case to case. Although the most hydrogen-rich cases resulted in red giants, cases with ≲ 0.01 M⊙ in the hydrogen envelope evolved at high ...
J. Katz, R. Malone, E. E. Salpeter
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