Extreme 13C,15N and 17O isotopic enrichment in the young planetary nebula K4-47

Schmidt, Deborah; Woolf, N. J.; Zega, T. J.; Ziurys, L. M.

doi:10.1038/s41586-018-0763-1

Cited by 16 publications

(12 citation statements)

References 33 publications

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“…Of additional interest are the surprising number of 13 C-substituted species, including CH 3 13 CN, c-CC 13 CH 2 , H 2 13 CO, and doubly substituted HC 3 N. Various molecules and their isotopic variants have been reported in our previous observations of K4-47 (HCN, H 13 CN, HC 15 N, HCO + , HNC, HN 13 C, CO, C 17 O, CS, 13 CS, CN, 13 CN, HC 3 N, H 13 CCCN, HC 13 CCN, and HCC 13 CN; see Schmidt et al 2018a). The appearance of the series H 13 C 13 CCN, HC 13 C 13 CN, and H 13 CC 13 CN marks the first time that all three isotopologues have been identified in one source.…”

Section: Resultsmentioning

confidence: 73%

“…The evolutionary sequence from the AGB to the PN phase is also reflected in the respective C, N, and O isotope ratios. With 12 C/ 13 C=2.2±0.8, 14 N/ 15 N=13.6±6.5, and 16 O/ 17 O= 21.4±10.3 (Schmidt et al 2018a), the isotope enhancement of 13 C, 15 N, and 17 O in K4-47 is clearly colossal. However, CRL 618 exhibits similar, although not as extreme, enrichments with 12 C/ 13 C∼9 and 14 N/ 15 N∼150 in its dense core (Lee et al 2013a).…”

Section: The Effects Of Nucleosynthesismentioning

confidence: 96%

“…It has a hot central core traced by highly excited atomic lines such as [O III], with high-velocity lobes at the tips of the outflow, visible in [N II] and [S II] (e.g., Corradi et al 2000). For many years, the only molecular emission known in this object was from CO and H 2 (Lumsden et al 2001;Huggins et al 2005), but newer studies have revealed the presence of CS, HCO + , HCN, HNC, CCH, and even HC 3 N, suggesting a very carbon-rich object Schmidt & Ziurys 2016, 2017a, 2017bSchmidt et al 2018a). Perhaps more striking are the anomalous isotope ratios recently found in K4-47, with 12 C/ 13 C=2.2±0.8, 14 N/ 15 N=13.6±6.5, and 16 O/ 17 O= 21.4±10.3 (Schmidt et al 2018a).…”

Section: Introductionmentioning

confidence: 99%

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Exotic Carbon Chemistry in a Planetary Nebula: The Unusual Case of K4-47

Schmidt

Ziurys

2019

ApJL

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Millimeter molecular line observations have been conducted toward the young (∼900 yr) bipolar planetary nebula (PN) K4-47, using the 12 m antenna and the Submillimeter Telescope of the Arizona Radio Observatory, and the Institut de Radioastronomie Millimétrique 30 m Telescope. Measurements at 1, 2, and 3 mm of multiple transitions were carried out to ensure the accuracy of all molecular identifications. K4-47 was found to be unusually chemically rich, containing three complex species, CH 3 CN, H 2 CNH, and CH 3 CCH, which have never before been observed in a planetary nebula. In addition, HC 3 N, N 2 H + , H 2 CO, cC 3 H 2 , and SiO have been identified in this object, as well as a variety of 13 C-substituted isotopologues (H 2 13 CO, c-13 CCCH 2 , c-CC 13 CH 2 , CH 3 13 CN, 13 CH 3 CN, CH 3 13 CCH, and 13 CH 3 CCH), including all three doubly 13 C-substituted varieties of HC 3 N-the first known object in which all three species have been detected. After CO and H 2 , the most abundant molecules in K4-47 are CCH and CN, which have abundances of f ∼8×10 −7 , relative to molecular hydrogen. Surprisingly, the next most abundant molecule is CH 3 CCH, which has f ∼6×10 −7 , followed by HCN with an abundance of ∼5×10 −7. The results suggest that K4-47 is the most chemically complex planetary nebula currently known. The molecular content of K4-47 closely resembles that of the C-star IRC+10216, but with lower abundances, except for HCO + , H 2 CO, and CH 3 CCH. The PN also chemically and morphologically resembles the bipolar protoplanetary nebula CRL 618, with similar enrichments of 13 C, 15 N, and 17 O, suggestive of an explosive process at the end of the asymptotic giant branch.

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Section: Resultsmentioning

confidence: 73%

Section: The Effects Of Nucleosynthesismentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

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Exotic Carbon Chemistry in a Planetary Nebula: The Unusual Case of K4-47

Schmidt

Ziurys

2019

ApJL

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“…It is as low as about 20 to 25 in the Galactic center region [21,26,27,28], increases to about 68 in the Solar neighborhood and even further in the outskirts of the Milky Way [21,29,30]. Much lower 12 C/ 13 C ratios than 20 were found in the envelopes of some late-type stars, for example ∼10 for CRL618 [12,31], ∼4 for CK Vulpécula [32], and ∼2 for K4−47 [14,33].…”

Section: Introductionmentioning

confidence: 95%

Rotational spectroscopy of singly 13C substituted isotopomers of propyne and determination of a semi-empirical equilibrium structure

Müller

Thorwirth

Lewen

2020

Journal of Molecular Structure

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Submillimeter spectra of three isotopomers of propyne containing one 13 C atom were recorded in natural isotopic composition in the region of 426 GHz to 785 GHz. Additional measurements were carried out near 110 GHz. Combining these with earlier data resulted in greatly improved spectroscopic parameters which permit reliable extrapolations up to about 1.5 THz. Coupled cluster quantum-chemical calculations were carried out in order to assess the differences between equilibrium and ground state rotational parameters of these and many other isotopic species to evaluate semi-empirical equilibrium structural parameters. In addition, we estimated the main spectroscopic parameters of the isotopomers of propyne with two 13 C atoms, which have not yet been studied in the laboratory, but which may be detectable in astronomical sources with a large amount of 13 C compared to the dominant 12 C.

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“…Stellar environments for the presolar SiC groups include: C-rich AGB stars with close-to-solar or higher metallicities (MS grains); C-rich AGB stars with sub-solar metallicity and/or greater than solar mass (Y and Z grains); CCSNe for X, C, and possibly the majority of U grains (Xu et al 2015); and novae and CCSNe for PNG grains (e.g., Nittler & Hoppe 2005;Liu et al 2016). The origin of AB grains is more ambiguous, and their proposed stellar sources include CCSNe, J-type C-stars, and novae (Liu et al 2017a;Schmidt et al 2018;Hoppe et al 2019). MS grains are the most common isotopic group, making up about 90% of all SiC grains, followed by AB (~5%), Y (~1-5%), Z (~1-5%), X (~1-2%), C (<1%), U (<1%), and PNG (<1%) grains.…”

Section: Introductionmentioning

confidence: 99%

TEM Analyses of Unusual Presolar Silicon Carbide: Insights into the Range of Circumstellar Dust Condensation Conditions

Singerling

Liu

Nittler

et al. 2021

ApJ

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Presolar silicon carbide (SiC) grains in meteoritic samples can help constrain circumstellar condensation processes and conditions in C-rich stars and core-collapse supernovae. This study presents our findings on eight presolar SiC grains from AGB stars (four mainstream and one Y grain) and core-collapse supernovae (three X grains), chosen on the basis of µ-Raman spectral features that were indicative of their having unusual non-3C polytypes and/or high degrees of crystal disorder. Analytical transmission electron microscopy (TEM), which provides elemental compositional and structural information, shows evidence for complex histories for the grains.Our TEM results confirm the presence of non-3C,2H crystal domains. Minor element heterogeneities and/or subgrains were observed in all grains analyzed for their compositions. The C/O ratios inferred for the parent stars varied from 0.98 to ≥1.03. Our data show that SiC condensation can occur under a wide range of conditions, in which environmental factors other than temperature (e.g., pressure, gas composition, heterogeneous nucleation on pre-condensed phases) play a significant role. Based on previous µ-Raman studies, ~10% of SiC grains may have infrared (IR) spectral features that are influenced by crystal defects, porosity, and/or

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Extreme 13C,15N and 17O isotopic enrichment in the young planetary nebula K4-47

Cited by 16 publications

References 33 publications

Exotic Carbon Chemistry in a Planetary Nebula: The Unusual Case of K4-47

Exotic Carbon Chemistry in a Planetary Nebula: The Unusual Case of K4-47

Rotational spectroscopy of singly 13C substituted isotopomers of propyne and determination of a semi-empirical equilibrium structure

TEM Analyses of Unusual Presolar Silicon Carbide: Insights into the Range of Circumstellar Dust Condensation Conditions

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