Results 121 to 130 of about 191,657 (282)
The Evolution of the Kinematics of Nebular Shells in Planetary Nebulae in the Milky Way Bulge
, 2010 We study the line widths in the [\ion{O}{3}]$\lambda$5007 and H$\alpha$ lines for two groups of planetary nebulae in the Milky Way bulge based upon spectroscopy obtained at the Observatorio Astron\'omico Nacional in the Sierra San Pedro M\'artir (OAN-SPM)
Aller +39 more
core +1 more source
Neutron-Capture Element Abundances in Planetary Nebulae
Galaxies, 2020 Nebular spectroscopy is a valuable tool for assessing the production of heavy elements by slow neutron(n)-capture nucleosynthesis (the s-process). Several transitions of n-capture elements have been identified in planetary nebulae (PNe) in the last few ...
N. C. Sterling
doaj +1 more source
Distances of Planetary Nebulae [PDF]
Symposium - International Astronomical Union, 1993 One of the most fundamental physical parameter in astronomy is the distance to the objects we detect in the universe. For many classes of astronomical objects, accurate and proven methods have been developed to determine their distances. Such classes of objects include stars within ∼100 pc from the sun, binary stellar systems, variable stars, stellar ...
openaire +2 more sources
Ionization correction factors for planetary nebulae – I. Using optical spectra [PDF]
, 2014 We compute a large grid of photoionization models that covers a wide range of physical parameters and is representative of most of the observed PNe. Using this grid, we derive new formulae for the ionization correction factors (ICFs) of He, O, N, Ne, S ...
G. Delgado-Inglada +6 more
semanticscholar +1 more source
Lawnmower Poetry and the Poetry of Lawnmowers
Critical Quarterly, EarlyView.
Francesca Gardner
wiley +1 more source
Northwest Africa 13489: A Strongly Metamorphosed Ungrouped Carbonaceous Chondrite
Meteoritics &Planetary Science, EarlyView.Abstract NWA 13489 is a meteorite that has been classified as a brachinite. Brachinites are olivine‐rich primitive achondrites representing residual products after a variable degree of silicate melt extraction on a barely differentiated, noncarbonaceous asteroid.
T. Cuppone +5 more
wiley +1 more source
Confronting expansion distances of planetary nebulae with Gaia DR2 measurements
, 2019 Individual distances to planetary nebulae are of the utmost relevance for our understanding of post-asymptotic giant-branch evolution because they allow a precise determination of stellar and nebular properties.
Schönberner, D., Steffen, M.
core +1 more source
Progenitors of Planetary Nebulae [PDF]
Symposium - International Astronomical Union, 1989 Over the past decade, we have come to realize that mass loss on the asymptotic giant branch (AGB) plays a significant role in the formation of planetary nebulae (PN). Mass ejected during the AGB can now be observed in haloes of PN and we believe that the main shell of PN is formed by the interaction of this material with a later-developed central-star ...
openaire +2 more sources
Measurements on Planetary Nebulae [PDF]
Symposium - International Astronomical Union, 1974 165 planetary nebulae south of +27° declination have been observed with the Parkes 64 m telescope. These nebulae were chosen to include most of those for which Hβ flux densities are available. Radio positions and flux densities (generally with probable errors of only a few millijanskies) obtained from the survey must represent the most reliable and ...
D. K. Milne, L. H. Aller
openaire +2 more sources
Weak magnetic fields in central stars of planetary nebulae [PDF]
, 2014 It is not yet clear whether magnetic fields play an essential role in shaping planetary nebulae (PNe), or whether stellar rotation alone and/or a close binary companion can account for the variety of the observed nebular morphologies.
M. Steffen +11 more
semanticscholar +1 more source