Discovery of Abundant In Situ Silicate and Spinel Grains from Red Giant Stars in a Primtive Meteorite

Details Discovery of Abundant In Situ Silicate and Spinel Grains from Red Giant Stars in a Primtive Meteorite Discovery of Abundant In Situ Silicate and Spinel Grains from Red Giant Stars in a Primtive Meteorite

Oct 2004

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004apj...613l.149m&link_type=abstract

The Astrophysical Journal, Volume 613, Issue 2, pp. L149-L152.

Astronomy and Astrophysics

Astronomy

74

Stars: Circumstellar Matter, Ism: Dust, Extinction, Galaxy: Evolution, Nuclear Reactions, Nucleosynthesis, Abundances

Scientific paper

We report the discovery of 12 in situ presolar silicate and spinel grains, 140-590 nm in size, in the Acfer 094 meteorite. These grains represent a matrix-normalized abundance of presolar O-rich dust of 170 parts per million. Among the 10 silicate grains are three olivines, four pyroxenes, and three grains with glasslike composition. Eleven grains have large excesses in 17O with 17O/16O ratios of up to 2.9 times the solar ratio and slightly lower than or close-to-solar 18O/16O ratios. These grains most likely formed in 1.5-1.65 Msolar red giant branch (RGB) or asymptotic giant branch (AGB) stars with close-to-solar metallicity. One pyroxene grain has close-to-solar 17O/16O and 18O/16O of 3.8 times solar. Silicon- and Fe-isotopic ratios of this grain are suggestive of the formation in an RGB or AGB star, probably with higher-than-solar metallicity. 29Si/28Si and 30Si/28Si ratios of the silicate grains vary by ~16%, are positively correlated with one another, and fall to the 30Si-poor side of the Si mainstream line characteristic for presolar SiC from AGB stars. This gives independent confirmation for the view that the Si mainstream line reflects the Galactic chemical evolution of the Si isotopes, except for a small shift due to dredge-up of matter from the He shell in AGB stars.

Affiliated with

Also associated with

No associations

Rating

Discovery of Abundant In Situ Silicate and Spinel Grains from Red Giant Stars in a Primtive Meteorite does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Discovery of Abundant In Situ Silicate and Spinel Grains from Red Giant Stars in a Primtive Meteorite, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Discovery of Abundant In Situ Silicate and Spinel Grains from Red Giant Stars in a Primtive Meteorite will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-897469