Circumstellar magnetite from the LAP 031117 CO3.0 chondrite

Thomas Zega, Pierre Haenecour, Christine Floss, Rhonda M. Stroud

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

We report the first microstructural confirmation of circumstellar magnetite, identified in a petrographic thin section of the LaPaz Icefield 031117 CO3.0 chondrite. The O-isotopic composition of the grain indicates an origin in a low-mass (∼2.2 M<inf>o.</inf>), approximately solar metallicity red/asymptotic giant branch (RGB/AGB) star undergoing first dredge-up. The magnetite is a single crystal measuring 750 × 670 nm, is free of defects, and is stoichiometric Fe<inf>3</inf>O<inf>4</inf>. We hypothesize that the magnetite formed via oxidation of previously condensed Fe dust within the circumstellar envelope of its progenitor star. Using an empirically derived rate constant for this reaction, we calculate that such oxidation could have occurred over timescales ranging from approximately ∼9000-500,000 years. This timescale is within the lifetime of estimates for dust condensation within RGB/AGB stars.

Original languageEnglish (US)
Article number55
JournalAstrophysical Journal
Volume808
Issue number1
DOIs
StatePublished - Jul 20 2015

Fingerprint

chondrites
chondrite
magnetite
asymptotic giant branch stars
dust
timescale
oxidation
dredger
thin section
metallicity
defect
condensation
isotopic composition
envelopes
crystal
stars
life (durability)
single crystals
defects
estimates

Keywords

  • circumstellar matter
  • stars: AGB and post-AGB
  • stars: evolution
  • stars: formation
  • stars: fundamental parameters
  • stars: winds outflows

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Circumstellar magnetite from the LAP 031117 CO3.0 chondrite. / Zega, Thomas; Haenecour, Pierre; Floss, Christine; Stroud, Rhonda M.

In: Astrophysical Journal, Vol. 808, No. 1, 55, 20.07.2015.

Research output: Contribution to journalArticle

Zega, Thomas ; Haenecour, Pierre ; Floss, Christine ; Stroud, Rhonda M. / Circumstellar magnetite from the LAP 031117 CO3.0 chondrite. In: Astrophysical Journal. 2015 ; Vol. 808, No. 1.
@article{e7fceace08c74430b56d88e4a8afacd0,
title = "Circumstellar magnetite from the LAP 031117 CO3.0 chondrite",
abstract = "We report the first microstructural confirmation of circumstellar magnetite, identified in a petrographic thin section of the LaPaz Icefield 031117 CO3.0 chondrite. The O-isotopic composition of the grain indicates an origin in a low-mass (∼2.2 Mo.), approximately solar metallicity red/asymptotic giant branch (RGB/AGB) star undergoing first dredge-up. The magnetite is a single crystal measuring 750 × 670 nm, is free of defects, and is stoichiometric Fe3O4. We hypothesize that the magnetite formed via oxidation of previously condensed Fe dust within the circumstellar envelope of its progenitor star. Using an empirically derived rate constant for this reaction, we calculate that such oxidation could have occurred over timescales ranging from approximately ∼9000-500,000 years. This timescale is within the lifetime of estimates for dust condensation within RGB/AGB stars.",
keywords = "circumstellar matter, stars: AGB and post-AGB, stars: evolution, stars: formation, stars: fundamental parameters, stars: winds outflows",
author = "Thomas Zega and Pierre Haenecour and Christine Floss and Stroud, {Rhonda M.}",
year = "2015",
month = "7",
day = "20",
doi = "10.1088/0004-637X/808/1/55",
language = "English (US)",
volume = "808",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "IOP Publishing Ltd.",
number = "1",

}

TY - JOUR

T1 - Circumstellar magnetite from the LAP 031117 CO3.0 chondrite

AU - Zega, Thomas

AU - Haenecour, Pierre

AU - Floss, Christine

AU - Stroud, Rhonda M.

PY - 2015/7/20

Y1 - 2015/7/20

N2 - We report the first microstructural confirmation of circumstellar magnetite, identified in a petrographic thin section of the LaPaz Icefield 031117 CO3.0 chondrite. The O-isotopic composition of the grain indicates an origin in a low-mass (∼2.2 Mo.), approximately solar metallicity red/asymptotic giant branch (RGB/AGB) star undergoing first dredge-up. The magnetite is a single crystal measuring 750 × 670 nm, is free of defects, and is stoichiometric Fe3O4. We hypothesize that the magnetite formed via oxidation of previously condensed Fe dust within the circumstellar envelope of its progenitor star. Using an empirically derived rate constant for this reaction, we calculate that such oxidation could have occurred over timescales ranging from approximately ∼9000-500,000 years. This timescale is within the lifetime of estimates for dust condensation within RGB/AGB stars.

AB - We report the first microstructural confirmation of circumstellar magnetite, identified in a petrographic thin section of the LaPaz Icefield 031117 CO3.0 chondrite. The O-isotopic composition of the grain indicates an origin in a low-mass (∼2.2 Mo.), approximately solar metallicity red/asymptotic giant branch (RGB/AGB) star undergoing first dredge-up. The magnetite is a single crystal measuring 750 × 670 nm, is free of defects, and is stoichiometric Fe3O4. We hypothesize that the magnetite formed via oxidation of previously condensed Fe dust within the circumstellar envelope of its progenitor star. Using an empirically derived rate constant for this reaction, we calculate that such oxidation could have occurred over timescales ranging from approximately ∼9000-500,000 years. This timescale is within the lifetime of estimates for dust condensation within RGB/AGB stars.

KW - circumstellar matter

KW - stars: AGB and post-AGB

KW - stars: evolution

KW - stars: formation

KW - stars: fundamental parameters

KW - stars: winds outflows

UR - http://www.scopus.com/inward/record.url?scp=84940403884&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84940403884&partnerID=8YFLogxK

U2 - 10.1088/0004-637X/808/1/55

DO - 10.1088/0004-637X/808/1/55

M3 - Article

AN - SCOPUS:84940403884

VL - 808

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 1

M1 - 55

ER -