Results 91 to 100 of about 50,898 (280)
Three Stages in Evolution of the Object Th4-4
GalaxiesThe results of observations of the object Th4-4 in 1970–2024 showed that during this period the object went through several stages, when its characteristics corresponded to different classes of objects: Be star, symbiotic star and planetary nebula ...
Lyudmila Kondratyeva +5 more
doaj +1 more source
Why all these ‘neos’? Why now?
Ciencias Sociales y Religión, 2021 This article starts with a critique of the current mainstream approaches that share the implicit assumptions of what I call the “secularization paradigm”, showing how and why these approaches are ill-suited to understand the importance and constitution ...
François Gauthier
doaj
Photoionization models of Planetary Nebulae [PDF]
, 2016 The understanding of astronomical nebulae is based on observational data (images, spectra, 3D data-cubes) and theoretical models. In this review, I present my very biased view on photoionization modeling of planetary nebulae, focusing on 1D multi-component models, on 3D models and on big database of models.
arxiv +1 more source
A recent change in the optical and γ-ray polarization of the Crab nebula and pulsar [PDF]
, 2015 We report on observations of the polarization of optical and γ-ray photons from the Crab nebula and pulsar system using the Galway Astronomical Stokes Polarimeter (GASP), the Hubble Space Telescope, Advanced Camera for Surveys and the International Gamma-
P. Moran +6 more
semanticscholar +1 more source
Herschel imaging and spectroscopy of the nebula around the luminous blue variable star WRAY 15-751 [PDF]
A&A, 557, A20 (17p, 2013), 2013 We have obtained far-infrared Herschel PACS imaging and spectroscopic observations of the nebular environment of the luminous blue variable WRAY 15-751. These images clearly show that the main, dusty nebula is a shell of radius 0.5 pc and width 0.35 pc extending outside the H-alpha nebula.
arxiv +1 more source
Constellations, EarlyView.ABSTRACT In the field of feminist methodology, participatory research designs are a means of choice to adequately involve affected groups of people and to conduct research as critical intervention. This article tackles this form of academic knowledge production and discusses how such positioned knowledge can be characterized more precisely in relation ...
Sabine Flick, Katharina Hoppe
wiley +1 more source
The Astrophysical JournalWe apply an imaging analysis technique to study the spatial distribution of the X-ray spectral hardness across the hot bubble of planetary nebula BD+30°3639.
Rodolfo Montez Jr.
doaj +1 more source
Backscattering and Line Broadening in Orion
The Astronomical Journal, 2022 Examination of emission lines in high-velocity-resolution optical spectra of the Orion Nebula confirms that the velocity component on the red wing of the main ionization front emission line is due to backscattering in the Photon Dominated Region.
C. R. O’Dell +2 more
doaj +1 more source
Observations of planetary nebulae in the Galactic Bulge [PDF]
arXiv, 1999 High quality spectrophotometric observations of 30 Planetary Nebulae in the Galactic Bulge have been made. Accurate reddenings, plasma parameters, and abundances of He,O,N,S,Ar,Cl are derived. We find the abundances of O,S,Ar in the Planetary Nebulae in the Galactic Bulge to be comparable with the abundances of the Planetary Nebulae in the Disk, high
arxiv
HI and CO Observations of Circumnebular Envelopes of Planetary Nebulae [PDF]
, 1994 21cm spectral-line and continuum observations of ten compact planetary nebulae have been made with the Very Large Array. Circumnebular atomic hydrogen is identified in the planetary nebulae SwSt1, M3-35, and possibly in Hu2-1. The possibility of an inverse correlation between the optical depth of circumnebular atomic hydrogen and the linear radius of ...
arxiv +1 more source