STELLAR ORIGINS OF EXTREMELY <sup>13</sup>C- AND <sup>15</sup>N-ENRICHED PRESOLAR SIC GRAINS: NOVAE OR SUPERNOVAE?

Liu, Nan; Nittler, L. R.; Alexander, Conel M. O'd.; Wang, Jingyuan; Pignatari, M.; José, J.; Nguyen, A. N.

doi:10.3847/0004-637x/820/2/140

Cited by 57 publications

(75 citation statements)

References 75 publications

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“…SiC grains on the three mounts were identified by automated BSE (backscattered electron)-EDX (energy-dispersive X-ray) analysis (Liu et al 2016a). Isotopic analysis of C, N, and Si in the AB2 and MS grains was performed with the NanoSIMS 50L ion microprobe at the Carnegie Institution using standard procedures (Liu et al 2016b(Liu et al , 2017. All data were collected in the imaging mode, with ~150 nm spatial resolution, which allowed selection of smaller regions of interest during data reduction to minimize potential contamination.…”

Section: Methodsmentioning

confidence: 99%

“…In contrast, the AB2 grains in this study show neutroncapture signatures that are even weaker than the s-process signatures and are thus inconsistent with being from born-again AGB stars (Liu et al 2014b). It should be pointed out that none of the AB1 grains have been clearly demonstrated to have come from born-again AGB stars (Liu et al 2016b(Liu et al , 2017. On the other hand, the graphite grains that have been assigned to a born-again AGB stellar origin (Jadhav et al 2013) could be alternatively explained by nucleosynthesis in supernovae with H ingestion (Liu et al 2017).…”

Section: Potential Stellar Origin(s) Of Ab2 Grainsmentioning

confidence: 99%

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J-type Carbon Stars: A Dominant Source of ¹⁴N-rich Presolar SiC Grains of Type AB

Liu

Stephan

Boehnke

et al. 2017

ApJL

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We report Mo isotopic data of 27 new presolar SiC grains, including 12 14 N-rich AB ( 14 N/ 15 N > 440, AB2) and 15 mainstream (MS) grains, and their correlated Sr and Ba isotope ratios when available. Direct comparison of the data for the MS grains, which came from lowmass asymptotic giant branch (AGB) stars with large s-process isotope enhancements, with the AB2 grain data demonstrates that AB2 grains show near-solar isotopic compositions and lack sprocess enhancements. The near-normal Sr, Mo, and Ba isotopic compositions of AB2 grains clearly exclude born-again AGB stars, where the intermediate neutron-capture process (iprocess) takes place, as their stellar source. On the other hand, low-mass CO novae, and early Rand J-type carbon stars show 13 C and 14 N excesses but no s-process enhancements and are thus potential stellar sources of AB2 grains. Since both early R-type carbon stars and CO novae are rare objects, the abundant J-type carbon stars (10−15% of all carbon stars) are thus likely to be a dominant source of AB2 grains.

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Section: Methodsmentioning

confidence: 99%

Section: Potential Stellar Origin(s) Of Ab2 Grainsmentioning

confidence: 99%

J-type Carbon Stars: A Dominant Source of ¹⁴N-rich Presolar SiC Grains of Type AB

Liu

Stephan

Boehnke

et al. 2017

ApJL

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“…However, the origin of the latter contribution is not well understood. In addition, counter-arguments favor a supernova origin for some of these "nova candidate" grains Liu et al 2016). Recently, the "first plausible grain of CO nova origin" has been reported, based on the measured C, N, Si, and S isotopic compositions, without requiring any mixing with solar-like matter (Haenecour et al 2016).…”

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confidence: 99%

On Presolar Stardust Grains from CO Classical Novae

Iliadis

Downen²,

José

et al. 2018

ApJ

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About 30%-40% of classical novae produce dust 20-100 days after the outburst, but no presolar stardust grains from classical novae have been unambiguously identified yet. Although several studies claimed a nova paternity for certain grains, the measured and simulated isotopic ratios could only be reconciled, assuming that the grains condensed after the nova ejecta mixed with a much larger amount of close-to-solar matter. However, the source and mechanism of this potential post-explosion dilution of the ejecta remains a mystery. A major problem with previous studies is the small number of simulations performed and the implied poor exploration of the large nova parameter space. We report the results of a different strategy, based on a Monte Carlo technique, that involves the random sampling over the most important nova model parameters: the white dwarf composition; the mixing of the outer white dwarf layers with the accreted material before the explosion; the peak temperature and density; the explosion timescales; and the possible dilution of the ejecta after the outburst. We discuss and take into account the systematic uncertainties for both the presolar grain measurements and the simulation results. Only those simulations that are consistent with all measured isotopic ratios of a given grain are accepted for further analysis. We also present the numerical results of the model parameters. We identify 18 presolar grains with measured isotopic signatures consistent with a CO nova origin, without assuming any dilution of the ejecta. Among these, the grains G270_2, M11-334-2, G278, M11-347-4, M11-151-4, and Ag2_6 have the highest probability of a CO nova paternity.

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“…Concerns about the likely nova paternity of these grains have been raised [47], after three additional micron-sized SiC grains were isolated from the Murchison meteorite with similar trends, but also with additional imprints (mainly non-solar Ti features), from which a (core-collapse) supernova origin cannot be excluded. Fourteen new submicron-to micron-sized 13 C-and 15 N-enriched presolar SiC grains from Murchison have also been recently reported [48]. In some of these grains, both nova and supernova origins are viable because explosive H-burning in the two stellar sites could result in quite similar proton-capture isotopic signatures.…”

Section: Nucleosynthesismentioning

confidence: 97%

Nucleosynthesis in Novae

José

2017

Proceedings of the 14th International Symposium on Nuclei in the Cosmos (NIC2016)

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Remarkable progress in our understanding of nova outbursts has been achieved through combined efforts in photometry, spectroscopy and numerical simulations. According to the thermonuclear runaway model, novae are powered by thermonuclear explosions in the H-rich envelopes transferred from a low-mass stellar companion onto a close white dwarf star. Extensive numerical simulations have shown that the accreted envelopes attain peak temperatures ranging between 100 and 400 MK, for about several hundred seconds, hence allowing extensive nuclear processing which eventually shows up in the form of nucleosynthetic fingerprints in the ejecta. Indeed, it has been claimed that novae can play a key role in the enrichment of the interstellar medium through a number of Al. At the turn of the XXI Century, classical novae entered the era of multidimensional models, which provide new insights into the physical mechanisms that drive mixing at the core-envelope interface. In this paper, we will present an overview on classical nova models, from the onset of accretion up to the explosion and ejection stages, with special emphasis on their gross observational properties and their associated nucleosynthesis. The impact of nuclear uncertainties on the final yields will be discussed.

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STELLAR ORIGINS OF EXTREMELY ¹³C- AND ¹⁵N-ENRICHED PRESOLAR SIC GRAINS: NOVAE OR SUPERNOVAE?

Abstract: Extreme excesses of 13 C ( 12 C/ 13

Cited by 57 publications

References 75 publications

J-type Carbon Stars: A Dominant Source of ¹⁴N-rich Presolar SiC Grains of Type AB

J-type Carbon Stars: A Dominant Source of ¹⁴N-rich Presolar SiC Grains of Type AB

On Presolar Stardust Grains from CO Classical Novae

Nucleosynthesis in Novae

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STELLAR ORIGINS OF EXTREMELY 13C- AND 15N-ENRICHED PRESOLAR SIC GRAINS: NOVAE OR SUPERNOVAE?

Abstract: Extreme excesses of 13 C ( 12 C/ 13

Cited by 57 publications

References 75 publications

J-type Carbon Stars: A Dominant Source of 14N-rich Presolar SiC Grains of Type AB

J-type Carbon Stars: A Dominant Source of 14N-rich Presolar SiC Grains of Type AB

On Presolar Stardust Grains from CO Classical Novae

Nucleosynthesis in Novae

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STELLAR ORIGINS OF EXTREMELY ¹³C- AND ¹⁵N-ENRICHED PRESOLAR SIC GRAINS: NOVAE OR SUPERNOVAE?

J-type Carbon Stars: A Dominant Source of ¹⁴N-rich Presolar SiC Grains of Type AB

J-type Carbon Stars: A Dominant Source of ¹⁴N-rich Presolar SiC Grains of Type AB