Results 71 to 80 of about 53,151 (238)

Clumps in the Planetary Nebulae [PDF]

open access: yesSymposium - International Astronomical Union, 1993
The effect of density and temperature fluctuations on the intensity of the recombination and collisionally excited lines is investigated.
A. F. Kholtygin, T. Kh. Feklistova
openaire   +2 more sources

Molecular Hydrogen Microstructures in Planetary Nebulae

open access: yesGalaxies, 2020
Molecular hydrogen (H 2 ) emission is commonly detected in planetary nebulae (PNe), specially in objects with bipolar morphologies. New studies showed that H 2 gas is also packed in microstructures embedded in PNe of any morphological type.
Stavros Akras   +3 more
doaj   +1 more source

Catalog of Planetary Nebulae Detected by GALEX and Corollary Optical Surveys

open access: yesThe Astrophysical Journal Supplement Series, 2023
Planetary nebulae (PNs) consist of an ionized envelope surrounding a hot central star (CSPN) that emits mostly at ultraviolet (UV) wavelengths. UV observations, therefore, provide important information on both the CSPN and the nebula. We have matched the
M. A. Gómez-Muñoz   +2 more
doaj   +1 more source

Planetary nebulae and how to find them: A concise review

open access: yesFrontiers in Astronomy and Space Sciences, 2022
This review provides useful background and information on how we find, vet and compile Planetary Nebulae (PNe) candidates and verify them. It presents a summary of the known Galactic PNe population and their curation in the Hong Kong/AAO/Strasbourg/Hα ...
Quentin A. Parker    +1 more
doaj   +1 more source

VIS‐to‐MIR reflectance and Raman spectroscopy of the CM2 NWA 12184 carbonaceous chondrite

open access: yesMeteoritics &Planetary Science, Volume 60, Issue 3, Page 570-595, March 2025.
Abstract The spectral analysis of CM meteorites can help to constrain the mineralogical composition of their parent body, the C‐type asteroids. The CM2 NWA 12184 was spectrally examined employing seven complementary techniques at different spatial resolutions, including VIS‐to‐MIR reflectance and Raman spectroscopy.
A. Galiano   +15 more
wiley   +1 more source

Molecular Envelopes of Planetary Nebulae and Proto-Planetary Nebulae [PDF]

open access: yesInternational Astronomical Union Colloquium, 1994
As stars evolve up the asymptotic giant branch (AGB), they begin to lose mass at a high rate, and in the process they create extended circumstellar molecular envelopes. Since the transition from AGB to planetary nebula stages is of the order of 1000 yr, the remnant of such molecular envelopes should still be observable in pro to-planetary nebulae (PPN)
openaire   +2 more sources

Irradiation Investigation: Exploring the Molecular Gas in NGC 7293

open access: yesGalaxies, 2020
Background: Many planetary nebulae retain significant quantities of molecular gas and dust despite their signature hostile radiation environments and energetic shocks.
Jesse Bublitz   +7 more
doaj   +1 more source

The Acceleration of the Nebular Shells in Planetary Nebulae in the Milky Way Bulge [PDF]

open access: yes, 2008
We present a systematic study of line widths in the [\ion{O}{3}]$\lambda$5007 and H$\alpha$ lines for a sample of 86 planetary nebulae in the Milky Way bulge based upon spectroscopy obtained at the \facility{Observatorio Astron\'omico Nacional in the Sierra San Pedro M\'artir (OAN-SPM)} using the Manchester Echelle Spectrograph.
arxiv   +1 more source

The Planetary Nebula Luminosity Function [PDF]

open access: yesProceedings of the International Astronomical Union, 2006
AbstractAlthough the method has no theoretical explanation, the [Oiii]λ5007Å planetary nebula luminosity function (PNLF) is an extremely valuable tool for obtaining accurate (< 10%) extragalactic distances out to ~ 18 Mpc. Because the PNLF works in large galaxies of all Hubble types, it is one of the best tools we have for cross-checking the results
openaire   +5 more sources

Neutron-Capture Element Abundances in Planetary Nebulae

open access: yesGalaxies, 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

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