Discovery of Rubidium, Cadmium, and Germanium Emission Lines in the Near-Infrared Spectra of Planetary Nebulae*

Sterling, N. C.; Dinerstein, H. L.; Kaplan, Kyle; Bautista, M. A.

doi:10.3847/2041-8205/819/1/l9

Cited by 37 publications

(56 citation statements)

References 41 publications

(77 reference statements)

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“…We calculated ionic and elemental abundances with the PyNeb analysis package , using the atomic data sources of García-Rojas et al (2015, see their Sterling et al (2016). To minimize uncertainties due to errors in the flux calibration or adopted extinction coefficients, we computed ionic abundances relative to nearby H I lines: 11-3 for lines with wavelengths ≤1.0 µm, Paβ for the J band, Brζ for H band lines, and Brγ in the K band.…”

Section: Line Measurements and Abundance Analysismentioning

confidence: 99%

“…-8 - Sterling et al (2015Sterling et al ( , 2016 for ncapture elements. Uncertainties to the ICFs are the recommendations of for O, S, and Ar, and were propagated from the ionic and elemental abundances used in the ICF prescriptions for n-capture elements.…”

Section: Line Measurements and Abundance Analysismentioning

confidence: 99%

“…Trans-iron elements can be produced by slow n-capture nucleosynthesis (the "s-process") in asymptotic giant branch (AGB) stars, and transported to the stellar envelope by third dredge-up (TDU) before being expelled via stellar winds and PN ejection (Karakas & Lattanzio 2014). Comparisons of empirically-determined s-process enrichments in PNe to theoretical predictions provide valuable constraints to models of AGB nucleosynthesis (Karakas et al 2009;Sterling et al 2016). …”

Section: Introductionmentioning

confidence: 99%

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NEUTRON-CAPTURE ELEMENT ABUNDANCES IN MAGELLANIC CLOUD PLANETARY NEBULAE^*

Mashburn

Sterling

Madonna

et al. 2016

ApJL

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We present near-infrared spectra of ten planetary nebulae (PNe) in the Large and Small Magellanic Clouds (LMC and SMC), acquired with the FIRE and GNIRS spectrometers on the 6.5-m Baade and 8.1-m Gemini South Telescopes, respectively. We detect Se and/or Kr emission lines in eight of these objects, the first detections of n-capture elements in Magellanic Cloud PNe. Our abundance analysis shows large s-process enrichments of Kr (0.6-1.3 dex) in the six PNe in which it was detected, and Se is enriched by 0.5-0.9 dex in five objects. We also estimate upper limits to Rb and Cd abundances in these objects. Our abundance results for the LMC are consistent with the hypothesis that PNe with 2-3 M ⊙ progenitors dominate the bright end of the PN luminosity function in young gasrich galaxies. We find no significant correlations between s-process enrichments and other elemental abundances, central star temperature, or progenitor mass, though this is likely due to our small sample size. We determine S abundances from our spectra and find that [S/H] agrees with [Ar/H] to within 0.2 dex for most objects, but is lower than [O/H] by 0.2-0.4 dex in some PNe, possibly due to O enrichment via third dredge-up. Our results demonstrate that n-capture elements can be detected in PNe belonging to nearby galaxies with ground-based telescopes, allowing s-process enrichments to be studied in PN populations with well-determined distances.

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Section: Line Measurements and Abundance Analysismentioning

confidence: 99%

Section: Line Measurements and Abundance Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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NEUTRON-CAPTURE ELEMENT ABUNDANCES IN MAGELLANIC CLOUD PLANETARY NEBULAE^*

Mashburn

Sterling

Madonna

et al. 2016

ApJL

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“…This is still a challenge and recent efforts have lead to observations (and sometimes first identifications) of emission lines from Se, Kr, Rb, Xe, Ca, K, Cr, Mn, Fe, Co, Ni, and Cu (García-Rojas et al 2015), and Cd, Ge and Rb in the infra-red (Sterling et al 2016). Ercolano (2006, at the IAU PNe symposium 234) focused her review on advances obtained in 3D modeling, models with dust and PDR regions.…”

Section: Introductionmentioning

confidence: 99%

Photoionization models of Planetary Nebulae

Morisset

2016

Proc. IAU

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“…Since its commissioning in 2014, many interesting results in the ISM have been explored by Sterling et al 2016;Afşar et al 2016;Oh et al 2016a;Oh et al 2016b;Lee et al 2016;Kaplan et al 2017). …”

Section: Introductionmentioning

confidence: 99%

Fluorescent H₂ Emission Lines from the Reflection Nebula NGC 7023 Observed with IGRINS

Pak

Kaplan

et al. 2017

ApJ

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We have analyzed the temperature, velocity and density of H 2 gas in NGC 7023 with a high-resolution near-infrared spectrum of the northwestern filament of the reflection nebula. By observing NGC 7023 in the H and K bands at R ≃ 45,000 with the Immersion GRating INfrared Spectrograph (IGRINS), we detected 68 H 2 emission lines within the 1 ′′ × 15 ′′ slit. The diagnostic ratios of 2-1 S(1)/1-0 S(1) is 0.41−0.56.In addition, the estimated ortho-to-para ratios (OPR) is 1.63−1.82, indicating that the H 2 emission transitions in the observed region arises mostly from gas excited by UV fluorescence. Gradients in the temperature, velocity, and OPR within the observed area imply motion of the photodissociation region (PDR) relative to the molecular cloud. In addition, we derive the column density of H 2 from the observed emission lines and compare these results with PDR models in the literature covering a range of densities and incident UV field intensities. The notable difference between PDR model predictions and the observed data, in high rotational J levels of ν = 1, is that the predicted formation temperature for newly-formed H 2 should be lower than that of the model predictions. To investigate the density distribution, we combine pixels in 1 ′′ × 1 ′′ areas and derive the density distribution at the 0.002 pc scale. The derived gradient of density suggests that NGC 7023 has a clumpy structure, including a high clump density of ∼10 5 cm −3 with a size smaller than ∼5 × 10 −3 pc embedded in lower density regions of 10 3 −10 4 cm −3 .

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Discovery of Rubidium, Cadmium, and Germanium Emission Lines in the Near-Infrared Spectra of Planetary Nebulae*

Cited by 37 publications

References 41 publications

NEUTRON-CAPTURE ELEMENT ABUNDANCES IN MAGELLANIC CLOUD PLANETARY NEBULAE^*

NEUTRON-CAPTURE ELEMENT ABUNDANCES IN MAGELLANIC CLOUD PLANETARY NEBULAE^*

Photoionization models of Planetary Nebulae

Fluorescent H₂ Emission Lines from the Reflection Nebula NGC 7023 Observed with IGRINS

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Discovery of Rubidium, Cadmium, and Germanium Emission Lines in the Near-Infrared Spectra of Planetary Nebulae*

Cited by 37 publications

References 41 publications

NEUTRON-CAPTURE ELEMENT ABUNDANCES IN MAGELLANIC CLOUD PLANETARY NEBULAE*

NEUTRON-CAPTURE ELEMENT ABUNDANCES IN MAGELLANIC CLOUD PLANETARY NEBULAE*

Photoionization models of Planetary Nebulae

Fluorescent H2 Emission Lines from the Reflection Nebula NGC 7023 Observed with IGRINS

Contact Info

Product

Resources

About

NEUTRON-CAPTURE ELEMENT ABUNDANCES IN MAGELLANIC CLOUD PLANETARY NEBULAE^*

NEUTRON-CAPTURE ELEMENT ABUNDANCES IN MAGELLANIC CLOUD PLANETARY NEBULAE^*

Fluorescent H₂ Emission Lines from the Reflection Nebula NGC 7023 Observed with IGRINS