on the stellar sources of presolar graphite

OXYGEN ISOTOPIC COMPOSITION OF PRESOLAR GRAPHITE GRAINS

Of presolar graphite grains, high-density graphite grains give us an unique oppor-tunity to probe low-metallicity AGB stars. Common stellar sources of KFB1 and KFC1 grains of high 12C/13C ratios (≥ 100) are considered to be low-mass (1.5 – 3M sun–3 –3

Stars in the Laboratory: Presolar Grains in Meteorites

flect those of their stellar sources. They thus serve as probes of the physical conditions inside stars and in supernova ejecta. Presola, grains identitied so far include SiC, diamond, graphite, silicon nitride, A1 2 03, and MgAIP4' This talk will discuss how these

Presolar dust grains from meteorites and their stellar sources

Figure 2 shows the types of presolar grains that have been identified to date. Also given in the figure are their sizes and most likely stellar sources. Diamond [Lewis et al., 1987], silicon carbide [Bernatowicz et al., 1987; Tang and Anders, 1988] and graphite

International Symposium on Nuclear Astrophysics

On the stellar sources of presolar graphite in primitive meteorites PoS(NIC-IX)019 pdf E. Zinner, S. Amari and M. Jadhav Isotopic Composition of Presolar Spinel Grain OC2: Constraining Intermediate-Mass Asymptotic Giant Branch Models PoS(NIC-IX)020 pdf

47th Lunar and Planetary Science Conference (2016) 2829.pdf

of individual presolar grains are the most effective way to constrain the stellar sources of these grains and gain information about their nucleosynthetic and chemical environments. Traditionally, destructive techniques like NanoSIMS and TEM of ultramicro

Ashes of Stars and Meteoritic Abundances: Nano Sims and Isotopic Abundances to Probe Stellar

Abundances to Probe Stellar Theory 18 Graphite Histograms of 12C/13C ratios of presolar graphite and SiC grains • Grains are round and typically 1 m in size and have a range in density of 1.6 to 2.2 g/cm • 12C/13C-distribution is clearly different to SiC 15N,

Missouri Space Grant Consortium Paper

2021/4/19Material identified as presolar isotopically includes nanometer-sized diamonds, micron-sized silicon carbide and graphite particles. We focus here on the spherical graphite particles, referred to as onions because of the concentric (001) graphite layers which form a rim.

Presolar Stardust in the Solar System

Oxides, Graphite Sources of Presolar Stardust Grains Stellar Evolution • Stars are powered by exothermic nuclear fusion reactions. Gravitational collapse occurs until hot enough for nuclear fuel to burn – e.g., 4 1 H - 4 He + 27 MeV • Energy release from

Structural, chemical, and isotopic microanalytical investigations of graphite

The growing list of presolar materials discovered in meteorites includes silicon carbide, nanodia-monds, silicon nitride, various magnesium, titanium, and alu-minum oxides, and graphite (Zinner, 1998), as well as refrac-tory Ti, V, Fe, Zr, Mo, Ru carbides and FeNi

Clues To Early History Of Solar System's Oldest Diamonds

The results are used to draw conclusions about the early history of stellar diamonds (Nature, August 9, 2001). Presolar grains known to be present in meteorites are thermally and chemically extremely stable minerals such as diamond, graphite, silicon carbide

MAIN RESEARCH INTERESTS

Presolar grains are characterized by unusual isotopic abundance anomalies attributed to a suite of nuclear processes that took place in their parent stellar sources (that is, grains must have formed around other stars prior to incorporation into the pre-solar nebula

Strontium and barium isotopes in presolar silicon carbide grains measured with

Presolar minerals identified to date include, e.g., diamond, silicon carbide (SiC), graphite, silicon nitride (Si 3N 4), oxi-des, and various types of silicates. Silicon carbide is the best characterized presolar mineral. Based on the isotopic com-positions of carbon

CiteSeerX — Constraints on stellar grain formation from

The spherules have 12C/13C ratios ranging over 3 orders of magnitude (from 0.02 to 80 times solar), clearly establishing their presolar origin as stellar condensates. These and other isotopic constraints point to a variety of stellar types as sources of the carbon, including low-mass asymptotic giant branch (AGB) stars and supernovae.

HE STROPHYSICAL OURNAL,472:760782,1996December1

STELLAR GRAIN FORMATION FROM PRESOLAR GRAPHITE 761 1.INTRODUCTION In recent years, the study of circumstellar and supernova grains extracted from primitive meteorites has provided a rich new source of information on stellar nucleosynthesis.7 The

Clues To Early History Of Solar System's Oldest Diamonds

The results are used to draw conclusions about the early history of stellar diamonds (Nature, August 9, 2001). Presolar grains known to be present in meteorites are thermally and chemically extremely stable minerals such as diamond, graphite, silicon carbide

(PDF) On the stellar sources of presolar graphite

On the stellar sources of presolar graphite Ernst Zinner* PoS(NIC-IX)019 E-mail: ekzwustl.edu Sachiko Amari E-mail: sawuphys.wustl.edu Manavi Jadhav E-mail The isolation of presolar graphite grains is difficult and they have been less well studied than presolar silicon carbide grains.

Stars in the Laboratory: Presolar Grains in Meteorites

flect those of their stellar sources. They thus serve as probes of the physical conditions inside stars and in supernova ejecta. Presola, grains identitied so far include SiC, diamond, graphite, silicon nitride, A1 2 03, and MgAIP4' This talk will discuss how these

J

On the other hand, low-mass CO novae and early R-and J-type carbon stars show C-13 and N-14 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.

Recent Progress in Presolar Grain Studies

Presolar grains are stardust that condensed in stellar outflows or stellar ejecta, and was incorporated in meteorites. They remain mostly intact throughout the journey from stars to the earth, keeping information of their birthplaces. Studies of presolar grains, which

On the stellar sources of presolar graphite in primitive

On the stellar sources of presolar graphite in primitive meteorites Zinner, Ernst; Amari, Sachiko; Jadhav, Manavi Abstract Ne, is characteristic of presolar graphite and led to its In SN grains it is due to the Publication: International Symposium on Nuclear 2006

(PDF) New Stellar Sources for High‐Density, Presolar

On the other hand, as seen in Fig- the Si/O zone of a 15 M SN, which has a high abundance of No. 2, 2008 NEW STELLAR SOURCES FOR PRESOLAR GRAPHITE The ratios are plotted as delta values. This grain has Ca and Ti isotopic patterns that are similar to those predicted for O-rich (O/C and O/Ne) zones of a 15 M SN and for the He shell of a 3 M AGB star with metallicity Z 0:003.

Define Presolar Grains : SkyFall Meteorites Glossary

Presolar grains in meteorites are recognized by their isotopically anomalous and highly unusual composition. Peter Hoppe's May, 2000 abstract in the paper "Presolar dust grains from meteorites and their stellar sources" provides an excellent baseline summary 1 that has been updated to

Extraterrestrial materials

Extraterrestrial material refers to natural objects now on Earth that originated in outer space. Such materials include cosmic dust and meteorites, as well as samples brought to Earth by sample return missions from the Moon, asteroids and comets, as well as solar wind particles. Extraterrestrial materials are of value to science as they

Presolar Grains: Outlook and Opportunities for Astrophysics

presolar grain from various stellar sources are generally roughly what is expected from astronomical estimates of stellar dust production rates that only require a few percent of the dust coming from supernovae (Alexander 1997).

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