Results 41 to 50 of about 212,521 (235)
H 2 in low-ionization structures of planetary nebulae [PDF]
, 2016 We report the detection of near-IR H$_2$ emission from the low-ionization structures (knots) in two planetary nebulae. The deepest ever, high-angular resolution H$_2$ 1-0 S(1) at 2.122$\mu$, H$_2$ 2-1 S(1) at 2.248$\mu$ and Br$\gamma$ images of K 4-47 ...
S. Akras +2 more
semanticscholar +1 more source
Planetary Nebulae Embryo after a Common Envelope Event
Galaxies, 2018 In the centers of some planetary nebulae are found close binary stars. The formation of those planetary nebulae was likely through a common envelope event, which transformed an initially-wide progenitor binary into the currently observed close binary ...
Natalia Ivanova, Jose L. A. Nandez
doaj +1 more source
The Hα surface brightness–radius relation: a robust statistical distance indicator for planetary nebulae [PDF]
, 2015 Measuring the distances to Galactic planetary nebulae (PNe) has been an intractable problem for many decades. We have now established a robust optical statistical distance indicator, the Hα surface brightness–radius or SHα–r relation, which addresses ...
D. Frew +7 more
semanticscholar +1 more source
Planetary Nebulae and the Ionization of the Interstellar Medium in Galaxies
Frontiers in Astronomy and Space Sciences, 2022 We discuss the role of planetary nebulae and their progeny in galaxy context in terms of ionization of the galaxy interstellar medium. This regards ionized gas outside the disk of spiral galaxies, the diffuse ionized medium in spiral galaxies, and the ...
Grażyna Stasińska +2 more
doaj +1 more source
An HST Snapshot Survey of Proto-Planetary Nebulae Candidates: Two Types of Axisymmetric Reflection Nebulosities [PDF]
ApJ, 528, 861, 1999 We report the results from an optical imaging survey of proto-planetary nebula candidates using the HST. We exploited the high resolving power and wide dynamic range of HST and detected nebulosities in 21 of 27 sources. All detected reflection nebulosities show elongation, and the nebula morphology bifurcates depending on the degree of the central star
arxiv +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
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
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
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
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
doaj +1 more source