88 citations · 748 across the 21 of their papers we have counts for
21 papers
New NanoSIMS Multielement Isotope Data Reveal CO Novae As Key Sources Of 13C-rich Presolar Silicon Carbide Grains
Jordi José, Nan Liu, Conel M. O'D. Alexander +1
We present new multielement NanoSIMS isotopic measurements (C, N, Si, Mg-Al, Ti, and Ni) for four putative nova SiC grains and 79 AB SiC grains from the Murchison meteorite to reas…
Explosive Nucleosynthesis in Core-Collapse Type II Supernovae: Insights from new C, N, Si, and Al-Mg isotopic compositions of presolar grains
Nan Liu, Conel M. O'D. Alexander, Bradley S. Meyer +3
We report C, N, Si, and Al-Mg isotope data for 39 presolar X silicon carbide (SiC) and four silicon nitride grains - a group of presolar grains that condensed in the remnants of co…
Presolar Silicon Carbide Grains of Types Y and Z: Their Strontium and Barium Isotopic Compositions and Stellar Origins
Nan Liu, Thomas Stephan, Sergio Cristallo +5
We report the Sr and Ba isotopic compositions of 18 presolar SiC grains of types Y (11) and Z (7), rare types commonly argued to have formed in lower-than-solar metallicity asympto…
Slow Neutron-Capture Process: Low-mass AGB stars and presolar silicon carbide grains
Nan Liu, Sergio Cristallo, Diego Vescovi
Presolar grains are microscopic dust grains that formed in the stellar winds or explosions of ancient stars that died before the formation of the solar system. The majority (~90% i…
Oxygen and Aluminum-Magnesium Isotopic Systematics of Presolar Nanospinel Grains from CI Chondrite Orgueil
Nan Liu, Nicolas Dauphas, Sergio Cristallo +2
Presolar oxide grains have been previously divided into several groups (Group 1 to 4) based on their isotopic compositions, which can be tied to several stellar sources. Much of av…
New Multielement Isotopic Compositions of Presolar SiC Grains: Implications for Their Stellar Origins
Nan Liu, Jens Barosch, Larry R. Nittler +5
We report NanoSIMS Si and Mg-Al isotopic data (and C, N, and Ti isotopic data when available) for 85 submicron- to micron-sized presolar SiC grains from the CM2 Murchison meteorite…
Cluster analysis of presolar silicon carbide grains: evaluation of their classification and astrophysical implications
Asmaa Boujibar, Samantha Howell, Shuang Zhang +9
Cluster analysis of presolar silicon carbide grains based on literature data for 12C/13C, 14N/15N, δ30Si/28Si, and δ29Si/28Si including or not inferred initial 26Al/27Al data, reve…
On the mass and metallicity distribution of parent AGB stars of presolar SiC
Sergio Cristallo, Ambra Nanni, Gabriele Cescutti +5
The vast majority (>=90%) of presolar SiC grains identified in primitive meteorites are relics of ancient asymptotic giant branch (AGB) stars, whose ejecta were incorporated into t…
Magnetic-buoyancy Induced Mixing in AGB Stars: Presolar SiC Grains
Diego Vescovi, Sergio Cristallo, Maurizio Busso +1
Isotope ratios can be measured in presolar SiC grains from ancient Asymptotic Giant Branch (AGB) stars at permil-level (0.1\%) precision. Such precise grain data permit derivation…
Presolar Silicon Carbide Grains of Types Y and Z: Their Molybdenum Isotopic Compositions and Stellar Origins
Nan Liu, Thomas Stephan, Sergio Cristallo +8
We report Mo isotopic compositions of 37 presolar SiC grains of types Y (19) and Z (18), rare types commonly argued to have formed in lower-than-solar metallicity asymptotic giant…
New constraints on the major neutron source in low-mass AGB stars
Nan Liu, Roberto Gallino, Sergio Cristallo +4
We compare updated Torino postprocessing asymptotic giant branch (AGB) nucleosynthesis model calculations with isotopic compositions of mainstream SiC dust grains from low-mass AGB…
Extremely Cr- and Ti-rich presolar oxide grains in a primitive meteorite: Formation in rare types of supernovae and implications for the astrophysical context of solar system birth
Larry R. Nittler, Conel M. O'D. Alexander, Nan Liu +1
We report the identification of 19 presolar oxide grains from the Orgueil CI meteorite with substantial enrichments in Cr, with Cr/Cr ratios ranging from 1.2 t…
Common Occurrence of Explosive Hydrogen Burning in Type II Supernovae
Nan Liu, Thomas Stephan, Patrick Boehnke +6
We report Mo isotopic data for 16 15N-rich presolar SiC grains of type AB (14N/15N<solar, AB1) and their correlated Sr and Ba isotope ratios when available. Eight of the 16 AB1 gra…
Late formation of silicon carbide in type II supernovae
Nan Liu, Larry R. Nittler, Conel O'M. D. Alexander +1
We have found that individual presolar silicon carbide (SiC) dust grains from supernovae show a positive correlation between 49Ti and 28Si excesses, which is attributed to the radi…
J-type carbon stars: A dominant source of 14N-rich presolar SiC grains of type AB
Nan Liu, Thomas Stephan, Patrick Boehnke +6
We report Mo isotopic data of 27 new presolar SiC grains, including 12 14N-rich AB (14N/15N>440, AB2) and 15 mainstream (MS) grains, and their correlated Sr and Ba isotope ratios w…
Stellar origin of 15N-rich presolar SiC grains of type AB: supernovae with explosive hydrogen burning
Nan Liu, Larry R. Nittler, Marco Pignatari +2
We report C, N, and Si isotopic data for 59 highly 13C-enriched presolar submicron- to micron-sized SiC grains from the Murchison meteorite, including eight putative nova grains (P…
Stellar Origins of Extremely - and -enriched Presolar SiC Grains: Novae or Supernovae?
Nan Liu, Larry R. Nittler, Conel M. O'D. Alexander +4
Extreme excesses of (/<10) and (/<20) in rare presolar SiC grains have been considered diagnostic of an origin in classical novae,…
The -pockets in AGB Stars and Their Fingerprints in Mainstream SiC Grains
Nan Liu, Andrew M. Davis, Roberto Gallino +5
We identify three isotopic tracers that can be used to constrain the -pocket and show the correlated isotopic ratios of Sr and Ba in single mainstream presolar SiC grains.…
Correlated Strontium and Barium Isotopic Compositions of Acid-Cleaned Single Silicon Carbides from Murchison
Nan Liu, Michael R. Savina, Roberto Gallino +8
We present strontium, barium, carbon, and silicon isotopic compositions of 61 acid-cleaned presolar SiC grains from Murchison. Comparison with previous data shows that acid washing…
The 13C-Pocket Structure in AGB Models: Constraints from Zirconium Isotope Abundances in Single Mainstream SiC Grains
Nan Liu, Roberto Gallino, Sara Bisterzo +3
We present postprocess AGB nucleosynthesis models with different C-pocket internal structures to better explain zirconium isotope measurements in mainstream presolar SiC gra…
Barium Isotopic Composition of Mainstream Silicon Carbides from Murchison: Constraints for s-Process Nucleosynthesis in AGB Stars
Nan Liu, Michael R. Savina, Andrew M. Davis +10
We present barium, carbon, and silicon isotopic compositions of 38 acid-cleaned presolar SiC grains from Murchison. Comparison with previous data shows that acid washing is highly…