Results 71 to 80 of about 48,210 (191)
MULTI-STAGES OPTIMIZED PHOTOIONIZATION MODELLING OF PLANETARY NEBULA LMC SMP-21
Odessa Astronomical Publications, 2012 The new approximation expression for the representation of gas density distribution in planetary nebulae envelopes was proposed. The new multi-stages method for the caclulation of the chemical composition and physical parameters of planetary nebulae ...
B. Ya. Melekh +5 more
doaj +1 more source
Classification of Planetary Nebulae through Deep Transfer Learning
Galaxies, 2020 This study investigate the effectiveness of using Deep Learning (DL) for the classification of planetary nebulae (PNe). It focusses on distinguishing PNe from other types of objects, as well as their morphological classification.
Dayang N. F. Awang Iskandar +6 more
doaj +1 more source
Planetary Nebulae Research: Past, Present, and Future [PDF]
Galaxies 2024, 12, 39We review the evolution of our understanding of the planetary nebulae phenomenon and their place in the scheme of stellar evolution. The historical steps leading to our current understanding of central star evolution and nebular formation are discussed.
arxiv +1 more source
Meteoritics &Planetary Science, Volume 60, Issue 3, Page 616-631, March 2025.Abstract Results of microanalysis study of NWA 869 meteorite, an ordinary chondrite, where silicates, Fe‐Ni alloys, and troilite are major constituents, are reported. The presented study of microtextures in metallic and sulfide grains provides information on processes occurring from the asteroid's accretion, through the impacts until cooling.
Paulina Skirak +4 more
wiley +1 more source
In Search of Possible Associations between Planetary Nebulae and Open Clusters [PDF]
, 2007 We consider the possibility of cluster membership for 13 planetary nebulae that are located in close proximity to open clusters lying in their lines of sight. The short lifetimes and low sample size of intermediate-mass planetary nebulae with respect to nearby open clusters conspire to reduce the probability of observing a true association.
arxiv +1 more source
Meteoritics &Planetary Science, Volume 60, Issue 2, Page 190-205, February 2025.Abstract The alignment of non‐spherical “flattened” chondrules into a petrofabric is a common feature of hydrated carbonaceous chondrite meteorites. This texture can form as a result of impacts at peak shock pressures exceeding 10 GPa. However, many carbonaceous chondrites with petrofabrics are unshocked.
Laura E. Jenkins +6 more
wiley +1 more source
A new Planetary Nebula in the outer reaches of the Galaxy [PDF]
, 2011 A proper determination of the abundance gradient in the Milky Way requires the observation of objects at large galactiocentric distances. With this aim, we are exploring the planetary nebula population towards the Galactic Anticentre. In this article, the discovery and physico-chemical study of a new planetary nebula towards the Anticentre direction ...
arxiv +1 more source
Properties of Proto--Planetary Nebulae [PDF]
arXiv, 2000 This review describes some general properites of proto-planetary nebulae with particular emphasis on the recent work of morpholgical studies. The weight of observational evidence shows that proto-planetary nebulae (PPNe) are most certainly axisymmetric like planetary nebulae.
arxiv
Planetary Nebulae in the Magellanic Clouds: Probing Stellar Evolution and Populations [PDF]
arXiv, 2002 This review contains: (1) the scientific motivations for studying Planetary Nebulae in the Magellanic Clouds; (2) a review of this field of study, from the origins to the most recent results, focusing on the papers that have been published since the last IAU Symposium on Planetary Nebulae; (3) a review of the Hubble contribution to the field, from the ...
arxiv
Ionization-bounded and Density-bounded Planetary Nebulae [PDF]
arXiv, 2009 Planetary nebulae (and in general any photoionized region) can be classified as ionization-bounded or density-bounded. It is important to determine in which case is the planetary nebula studied to be able to estimate from nebular observations, for example, the total rate of ionizing photons produced by the central star.
arxiv