Results 71 to 80 of about 191,657 (282)
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
openaire +7 more sources
Expansion patterns and parallaxes for planetary nebulae
, 2018 Aims. We aim to determine individual distances to a small number of rather round, quite regularly shaped planetary nebulae by combining their angular expansion in the plane of the sky with a spectroscopically measured expansion along the line of sight ...
D. Schönberner, B. Balick, R. Jacob
semanticscholar +1 more source
BINARITY AND THE ABUNDANCE DISCREPANCY PROBLEM IN PLANETARY NEBULAE [PDF]
, 2015 The discrepancy between abundances computed using optical recombination lines and collisionally excited lines is a major unresolved problem in nebular astrophysics.
R. Corradi +3 more
semanticscholar +1 more source
New groups of planetary nebulae with peculiar dust chemistry towards the Galactic bulge
, 2010 We investigate Galactic bulge planetary nebulae without emission-line central stars for which peculiar infrared spectra have been obtained with the Spitzer Space Telescope, including the simultaneous signs of oxygen and carbon based dust.
Blöcker +51 more
core +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
doaj +1 more source
A Preferred Orientation Angle for Bipolar Planetary Nebulae
Galaxies, 2020 We present preliminary results from measuring Galactic orientation angles of 766 elliptical and bipolar Planetary Nebulae (PNe) in the Hong Kong/Australian Astronomical Observatory/Strasbourg Observatory H-alpha Planetary Nebula research platform and ...
Andreas Ritter, Quentin A. Parker
doaj +1 more source
Oxygen enrichment in carbon-rich planetary nebulae [PDF]
, 2015 We study the relation between the chemical composition and the type of dust present in a group of 20 Galactic planetary nebulae (PNe) that have high quality optical and infrared spectra.
G. Delgado-Inglada +4 more
semanticscholar +1 more source
The Planetary Nebulae Spectrograph: the green light for Galaxy Kinematics [PDF]
, 2002 Planetary nebulae are now well established as probes of galaxy dynamics and as standard candles in distance determinations. Motivated by the need to improve the efficiency of planetary nebulae searches and the speed with which their radial velocities are
A. J. Romanowsky +19 more
core +4 more sources
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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The post-common envelope central stars of the planetary nebulae Henize 2-155 and Henize 2-161 [PDF]
, 2015 We present a study of Hen 2-155 and Hen 2-161, two planetary nebulae which bear striking morphological similarities to other planetary nebulae known to host close-binary central stars.
David Jones +6 more
semanticscholar +1 more source