TY - JOUR
T1 - A seed of solar forsterite and possible new evolutional scenario of cosmic silicates
AU - Kimura, Yuki
AU - Nuth, Joseph A.
N1 - Funding Information:
TEM analysis was performed in the Electron Microbeam Analyses Facility of the Department of Earth and Planetary Sciences at the University of New Mexico, where Adrian J. Brearley and Ying-Bing Jiang provided technical support. This work was partially supported by grants from the Japan Society for the Promotion of Science (JSPS) Postdoctoral Fellowships for Research Abroad from 2004 April to 2006 March and a Grant-in-Aid for Young Scientists (start-up) from KAKEHI (19840048) of JSPS from 2006 April to 2008 March. This work was also supported in part by Tohuku University Global COE program for the “Global Education and Research Center for Earth and Planetary Dynamics”.
PY - 2009
Y1 - 2009
N2 - Laboratory experiments suggest that magnesium silicide (Mg2Si) grains could be produced in the hydrogen dominant gas outflow from evolved stars in addition to amorphous oxide minerals. If the magnesium silicide grains were incorporated into the primitive solar nebula, the magnesium silicide would easily become forsterite (Mg2SiO4) by oxidation as it reacted with the relatively oxygen-rich, solar composition gas. This hypothesis can explain the existence of abundant forsterite grains with solar oxygen composition in meteorites, i.e., magnesium silicide could be the precursor of much of the forsterite found in our solar system. In addition, if a significant fraction of the solar forsterite is derived from magnesium silicide, it could explain the apparent low abundance of presolar forsterite. Furthermore, the lower degree of crystallinity observed in silicates formed in outflows of lower mass-loss-rate stars might be caused by the formation of magnesium silicide in this relatively hydrogen-rich environment.
AB - Laboratory experiments suggest that magnesium silicide (Mg2Si) grains could be produced in the hydrogen dominant gas outflow from evolved stars in addition to amorphous oxide minerals. If the magnesium silicide grains were incorporated into the primitive solar nebula, the magnesium silicide would easily become forsterite (Mg2SiO4) by oxidation as it reacted with the relatively oxygen-rich, solar composition gas. This hypothesis can explain the existence of abundant forsterite grains with solar oxygen composition in meteorites, i.e., magnesium silicide could be the precursor of much of the forsterite found in our solar system. In addition, if a significant fraction of the solar forsterite is derived from magnesium silicide, it could explain the apparent low abundance of presolar forsterite. Furthermore, the lower degree of crystallinity observed in silicates formed in outflows of lower mass-loss-rate stars might be caused by the formation of magnesium silicide in this relatively hydrogen-rich environment.
KW - Dust, extinction
KW - Infrared: solar system
KW - Infrared: stars
KW - Methods: laboratory
KW - Solar system: general
KW - Stars: AGB and post-AGB
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U2 - 10.1088/0004-637X/697/1/L10
DO - 10.1088/0004-637X/697/1/L10
M3 - Article
AN - SCOPUS:67649140905
VL - 697
SP - L10-L13
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 1 PART 2
ER -