scholarly journals Neutron-capture Elements in Planetary Nebulae: First Detections of Near-infrared [Te iii] and [Br v] Emission Lines

2018 ◽  
Vol 861 (1) ◽  
pp. L8 ◽  
Author(s):  
Simone Madonna ◽  
Manuel Bautista ◽  
Harriet L. Dinerstein ◽  
N. C. Sterling ◽  
Jorge García-Rojas ◽  
...  
Keyword(s):  
Neutron Capture ◽  
Near Infrared ◽  
Planetary Nebulae ◽  
Emission Lines

scholarly journals Infrared Emission-Lines and the Stellar Temperature

1993 ◽  
Vol 155 ◽  
pp. 89-89 ◽  
Author(s):  
Sueli M. Viegas ◽  
Ruth Gruenwald
Keyword(s):  
Near Infrared ◽  
Planetary Nebulae ◽  
Infrared Emission ◽  
Emission Lines ◽  
Heavy Elements ◽  
Atomic Transitions ◽  
Stellar Temperature ◽  
Near Infrared Emission

Observations of near infrared emission-lines are becoming available and can be a powerful tool to improve our knowledge on planetary nebulae properties. For wavelengths in the range 1 to 5 μm, the emission-lines correspond to atomic transitions of high ionized species of heavy elements. In particular, the [Si VI] 1.96μm and [Si VII] 2.48μm lines have already been detected (Ashley and Hyland, 1988).

scholarly journals Near-Infrared Spectroscopy of H2 in Proto-Planetary Nebulae

2003 ◽  
Vol 209 ◽  
pp. 269-270
Author(s):  
Douglas M. Kelly ◽  
Bruce J. Hrivnak
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Spectral Range ◽  
Near Infrared ◽  
Planetary Nebulae ◽  
Emission Lines ◽  
Complete Sample

We measured 2.1 – 2.3 μm spectra for a fairly complete sample of known proto-planetary nebulae (PPN) at declinations greater than -30°. This spectral range includes the H2 emission lines 1-0 S(1), 1-0 S(0), 2-1 S(1), 2-1 S(2), and 3-2 S(3). We detected H2 emission from 16 of the 51 nebulae in our survey, including radiatively-excited H2 from several non-bipolar PPN.

scholarly journals Neutron-Capture Element Abundances in Planetary Nebulae

Galaxies ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 50
Author(s):  
N. C. Sterling
Keyword(s):  
Neutron Capture ◽  
Observational Studies ◽  
Near Infrared ◽  
Dwarf Galaxy ◽  
Planetary Nebulae ◽  
Slow Neutron ◽  
Magellanic Clouds ◽  
Heavy Elements ◽  
Element Abundances ◽  
Open Questions

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 years, with the aid of sensitive, high-resolution, near-infrared spectrometers. Combined with optical spectroscopy, the newly discovered near-infrared lines enable more accurate abundance determinations than previously possible, and provide access to elements that had not previously been studied in PNe or their progenitors. Neutron-capture elements have also been detected in PNe in the Sagittarius Dwarf galaxy and in the Magellanic Clouds. In this brief review, I discuss developments in observational studies of s-process enrichments in PNe, with an emphasis on the last five years, and note some open questions and preliminary trends.

scholarly journals Near Infrared Emission of Neutral Carbon from Photon-Dominated Regions

1992 ◽  
Vol 150 ◽  
pp. 333-334
Author(s):  
V. Escalante ◽  
A. Sternberg ◽  
A. Dalgarno
Keyword(s):  
Field Intensity ◽  
Radiative Recombination ◽  
Near Infrared ◽  
Planetary Nebulae ◽  
Infrared Emission ◽  
Emission Lines ◽  
Radiation Fields ◽  
Ngc 7027 ◽  
Near Infrared Emission ◽  
Intense Radiation

Detailed calculations are reported of the intensities of the near infrared forbidden lines of neutral carbon atoms at λ 985.0 nm, 982.3 nm and 872.7 nm emitted from dense clouds subjected to intense radiation fields. The metastable levels that produce the lines are excited by radiative recombination of the C+ ions produced by photoionization. Impacts of electrons with C atoms in the heated edge zones of the clouds contribute an insignificant part to the excitation. The lines observed in M42 and NGC 2024 can be interpreted as arising in gas with densities in excess of 105 cm−3 and radiation fields with intensities between 103 and 106 times the average interstellar field intensity. Radiative recombination of C+ ions may also be an important source of the emission lines detected in the planetary nebulae NGC 6270 and NGC 7027.

IR Fabry-Perot imaging of NGC 3132

1997 ◽  
Vol 180 ◽  
pp. 205-205
Author(s):  
L. E. Allen ◽  
M.C.B. Ashley ◽  
S. D. Ryder ◽  
J.W.V. Storey ◽  
Y-S. Sun ◽  
...  
Keyword(s):  
Planetary Nebula ◽  
Near Infrared ◽  
New South ◽  
New South Wales ◽  
Planetary Nebulae ◽  
Emission Lines ◽  
South Wales ◽  
Fabry Perot

Near-infrared (1-3μm) emission lines of molecular and ionized hydrogen are excellent tools for investigating the morphology, energetics and kinematics of planetary nebulae, especially those PNe which contain large amounts of dust and are thus obscured at shorter wavelengths. The southern planetary nebula NGC 3132 was imaged with UNSWIRF (University of New South Wales Infrared Fabry-Perot) and IRIS on the 3.9m AAT Images in the H2 v=1-0 S(1) and H2 v=2-1 S(1) lines at 2.12μm and 2.25μm, and in Hii Brγ at 2.16μm are presented.

scholarly journals A Study of the Planetary Nebulae Abell 30 and Abell 78

1978 ◽  
Vol 76 ◽  
pp. 356-356
Author(s):  
M. Cohen ◽  
H.S. Hudson ◽  
S.L. O'Dell ◽  
W.A. Stein
Keyword(s):  
Near Infrared ◽  
Planetary Nebulae ◽  
Emission Lines ◽  
Infrared Photometry ◽  
Colour Temperature ◽  
Royal Astronomical Society ◽  
Excess Emission ◽  
Central Regions ◽  
Ubvri Photometry ◽  
Stellar Temperatures

We have studied the central regions of the planetary nebulae A 30 and A 78 by UBVRI photometry, optical spectroscopy, and near-infrared photometry. The spectra contain high-excitation emission lines and strongly resemble those of Wolt-Rayet stars of the carbon sequence. We infer stellar temperatures > 50,000°K. The observed 3.5-ym flux of each nebula exceeds reasonable extrapolations of both the stellar flux and any possible free-free emission. The colour temperature of this excess between 2.28 and 3.5 /im is ∼ 1000°K. For each nebula, the aperture dependence of the excess emission suggests an extended (y10 arc-sec radius) region centred on the nucleus. Thermal radiation from a distribution of dust that is concentrated near the nuclei seems the most plausible explanation for the excess, but no theory of dust formation or heating seems totally adequate at present. (Paper will appear in the Monthly Notices of the Royal Astronomical Society.)

scholarly journals Emission Lines in the Near Infrared Spectra of Faint Planetary Nebulae

1978 ◽  
Vol 76 ◽  
pp. 123-124
Author(s):  
Yvette Andrillat ◽  
Léo Houziaux
Keyword(s):  
Spectral Range ◽  
Infrared Spectra ◽  
Near Infrared ◽  
Planetary Nebulae ◽  
Emission Lines ◽  
Image Tube ◽  
Near Infrared Spectra

We obtained spectra of twelve faint planetary nebulae at the Cassegrain focus of the 193 cm telescope at Haute Provence Observatory (dispersion: 230 Åmm−1 spectral range 8000–11000 Å, receiver: ITT image tube with SI photocathode).

scholarly journals DISCOVERY OF RUBIDIUM, CADMIUM, AND GERMANIUM EMISSION LINES IN THE NEAR-INFRARED SPECTRA OF PLANETARY NEBULAE

2016 ◽  
Vol 819 (1) ◽  
pp. L9 ◽  
Author(s):  
N. C. Sterling ◽  
Harriet L. Dinerstein ◽  
Kyle F. Kaplan ◽  
Manuel A. Bautista
Keyword(s):  
Infrared Spectra ◽  
Near Infrared ◽  
Planetary Nebulae ◽  
Emission Lines ◽  
Near Infrared Spectra

scholarly journals Identification of Near-infrared [Se iii] and [Kr vi] Emission Lines in Planetary Nebulae

2017 ◽  
Vol 840 (2) ◽  
pp. 80 ◽  
Author(s):  
N. C. Sterling ◽  
S. Madonna ◽  
K. Butler ◽  
J. García-Rojas ◽  
A. L. Mashburn ◽  
...  
Keyword(s):  
Near Infrared ◽  
Planetary Nebulae ◽  
Emission Lines
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