Astrogeology

Oxygen Isotope Exchange Between Molten Silicate Spherules and Ambient Water Vapor with Nonzero Relative Velocity: Implication for Chondrule Formation Environment

By Keith Cowing
Status Report
astro-ph.EP
June 26, 2023
Filed under , , , ,
Oxygen Isotope Exchange Between Molten Silicate Spherules and Ambient Water Vapor with Nonzero Relative Velocity: Implication for Chondrule Formation Environment
Timescale for isotope exchange reaction, τ, as a function of Pwater and vrel (solid lines). The vertical dashed line represents vrel at s16 = 0.2 (see Section 3.1.2). Here, we set T = 2000 K, r = 0.5 mm, χ = 1, and β16 = 0.3. The dashed lines represent the timescale of homogenization, τhomo, as a function of PH2 and vrel (see Section 4.2). — astro-ph.EP

Oxygen isotope compositions of chondrules reflect the environment of chondrule formation and its spatial and temporal variations.

Here, we present a theoretical model of oxygen isotope exchange reaction between molten silicate spherules and ambient water vapor with finite relative velocity. We found a new phenomenon, that is, mass-dependent fractionation caused by isotope exchange with ambient vapor moving with nonzero relative velocity.

We also discussed the plausible condition for chondrule formation from the point of view of oxygen isotope compositions.

Our findings indicate that the relative velocity between chondrules and ambient vapor would be lower than several 100 m/s when chondrules crystallized.

Sota Arakawa, Daiki Yamamoto, Takayuki Ushikubo, Hiroaki Kaneko, Hidekazu Tanaka, Shigenobu Hirose, Taishi Nakamoto

Comments: 15 pages, 8 figures. Accepted for publication in Icarus
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Soft Condensed Matter (cond-mat.soft); Chemical Physics (physics.chem-ph); Geophysics (physics.geo-ph)
Cite as: arXiv:2306.14413 [astro-ph.EP] (or arXiv:2306.14413v1 [astro-ph.EP] for this version)
Submission history
From: Sota Arakawa
[v1] Mon, 26 Jun 2023 04:31:38 UTC (805 KB)
https://arxiv.org/abs/2306.14413
Astrobiology, Astrochemistry,

Keith Cowing

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻

Follow on Twitter
MORE FROM Astrogeology