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

Abstract

We report Mo isotopic data of 27 new presolar SiC grains, including 12 {sup 14}N-rich AB ({sup 14}N/{sup 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 low-mass 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 s -process 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 ( i -process) takes place, as their stellar source. On the other hand, low-mass CO novae and early R- and J-type carbon stars show {sup 13}C and {sup 14}N excesses but no s -process enhancements and are thus potential stellar sources of AB2 grains. Because 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.

Authors:
; ; ;  [1]; ; ; ; ;  [2]
  1. Department of Terrestrial Magnetism, Carnegie Institution for Science, Washington, DC 20015 (United States)
  2. Department of the Geophysical Sciences, The University of Chicago, Chicago, IL 60637 (United States)
Publication Date:
OSTI Identifier:
22654430
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 844; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CARBON STARS; ISOTOPE RATIO; MOLYBDENUM ISOTOPES; SILICON CARBIDES; SPACE; STARS

Citation Formats

Liu, Nan, Nittler, Larry R., Alexander, Conel M. O’D., Wang, Jianhua, Stephan, Thomas, Boehnke, Patrick, Davis, Andrew M., Trappitsch, Reto, and Pellin, Michael J., E-mail: nliu@carnegiescience.edu. J-type Carbon Stars: A Dominant Source of {sup 14}N-rich Presolar SiC Grains of Type AB. United States: N. p., 2017. Web. doi:10.3847/2041-8213/AA7D4C.
Liu, Nan, Nittler, Larry R., Alexander, Conel M. O’D., Wang, Jianhua, Stephan, Thomas, Boehnke, Patrick, Davis, Andrew M., Trappitsch, Reto, & Pellin, Michael J., E-mail: nliu@carnegiescience.edu. J-type Carbon Stars: A Dominant Source of {sup 14}N-rich Presolar SiC Grains of Type AB. United States. doi:10.3847/2041-8213/AA7D4C.
Liu, Nan, Nittler, Larry R., Alexander, Conel M. O’D., Wang, Jianhua, Stephan, Thomas, Boehnke, Patrick, Davis, Andrew M., Trappitsch, Reto, and Pellin, Michael J., E-mail: nliu@carnegiescience.edu. Thu . "J-type Carbon Stars: A Dominant Source of {sup 14}N-rich Presolar SiC Grains of Type AB". United States. doi:10.3847/2041-8213/AA7D4C.
@article{osti_22654430,
title = {J-type Carbon Stars: A Dominant Source of {sup 14}N-rich Presolar SiC Grains of Type AB},
author = {Liu, Nan and Nittler, Larry R. and Alexander, Conel M. O’D. and Wang, Jianhua and Stephan, Thomas and Boehnke, Patrick and Davis, Andrew M. and Trappitsch, Reto and Pellin, Michael J., E-mail: nliu@carnegiescience.edu},
abstractNote = {We report Mo isotopic data of 27 new presolar SiC grains, including 12 {sup 14}N-rich AB ({sup 14}N/{sup 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 low-mass 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 s -process 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 ( i -process) takes place, as their stellar source. On the other hand, low-mass CO novae and early R- and J-type carbon stars show {sup 13}C and {sup 14}N excesses but no s -process enhancements and are thus potential stellar sources of AB2 grains. Because 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.},
doi = {10.3847/2041-8213/AA7D4C},
journal = {Astrophysical Journal Letters},
number = 1,
volume = 844,
place = {United States},
year = {Thu Jul 20 00:00:00 EDT 2017},
month = {Thu Jul 20 00:00:00 EDT 2017}
}