Results 11 to 20 of about 1,583 (233)
The Astrophysical Journal Letters, 2022 We report the discovery of giant (50−100 kpc) [O ii ] emitting nebulae with MUSE in the field of TXS 0206−048, a luminous quasar at z = 1.13. “Down-the-barrel” UV spectra of the quasar show absorption at velocities coincident with those of the extended ...
Sean D. Johnson +12 more
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M 1–92 Revisited: New Findings and Open Questions: New NOEMA Observations of Minkowski’s Footprint
Galaxies, 2022 PN M 1–92, also known as Minkowski’s Footprint, is a textbook example of a massive pre-planetary nebula. It presents all the characteristics of this type of source: non-spherical symmetry (bipolar cylindrical symmetry in this case), high-velocity gas ...
Javier Alcolea +7 more
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S II emission lines in Planetary Nebulae [PDF]
Symposium - International Astronomical Union, 1997 Emission lines arising from transitions in S II have been detected in a wide variety of astronomical sources, including planetary nebulae (Hyung, Keyes & Aller 1995). These transitions are used to derive information on emitting plasmas parameters (Te, Ne) through diagnostic line ratios, although to calculate these quantities reliably, accurate ...
Kenneth L. Bell +5 more
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The Astrophysical Journal, 2023 We have studied the evolution of HuBi 1–like planetary nebulae, considering several stages of mass injection. We have carried out numerical ionization+1D hydrodynamics+atomic/ionic rate models with our code Coral1d to reproduce planetary nebulae that ...
Ary Rodríguez-González +6 more
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A Spatially Resolved X-Ray Polarization Map of the Vela Pulsar Wind Nebula
The Astrophysical Journal Letters, 2023 In this paper, we present a full spatially resolved polarization map for the Vela pulsar wind nebula (PWN) observed by IXPE. By employing effective background discrimination techniques, our results show a remarkably high degree of local polarization in ...
Kuan Liu +14 more
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Maser emission in planetary nebulae [PDF]
Proceedings of the International Astronomical Union, 2007 AbstractStars at the top of the asymptotic giant branch (AGB) can exhibit maser emission from molecules like SiO, H2O and OH. These masers appear in general stratified in the envelope, with the SiO masers close to the central star and the OH masers farther out in the envelope.
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The influence of planetary nebula gas density fluctuations to its emission line spectra
Вісник Астрономічної школи, 2000 The set of spheric-simmetrical photoionization models of planetary nebula luminescence for different radial gas density distributions for central stars temperatures T = 50000 K and T = 100000 K was created.
N. V. Gavrilova, N. L. Tishko
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The Astrophysical Journal, 1993 The formation and destruction processes of HeH + in nebulae are discussed, and calculations of the abundances of HeH + are presented. It is shown that for effective temperatures of the ionizing source exceeding 50,000 K, the abundances are of the order of 10 12 cm −2 , largely independent of the nebular parameters.
Alexander Dalgarno +1 more
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Evidence for the Disruption of a Planetary System During the Formation of the Helix Nebula
The Astronomical Journal, 2022 The persistence of planetary systems after their host stars evolve into their post-main-sequence phase is poorly constrained by observations. Many young white dwarf systems exhibit infrared excess emission and/or spectral absorption lines associated with
Jonathan P. Marshall +7 more
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The Continuum Emission from Planetary Nebulae [PDF]
Symposium - International Astronomical Union, 1988 The study of nebular continuum emission is important for several reasons (Pottasch 1984, Planetary Nebulae, Dordrecht: Reidel). First of all, it can provide information about the temperature and the density of the nebula, when the object is large enough, or when the central star is weak enough, so that the nebular continuum is easily observed without ...
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