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Record W2220390127 · doi:10.1088/0004-637x/809/1/6

NATURE’S STARSHIPS. II. SIMULATING THE SYNTHESIS OF AMINO ACIDS IN METEORITE PARENT BODIES

2015· article· en· W2220390127 on OpenAlexaff
Alyssa K. Cobb, Ralph E. Pudritz, Ben K. D. Pearce

Bibliographic record

VenueThe Astrophysical Journal · 2015
Typearticle
Languageen
FieldPhysics and Astronomy
TopicAstro and Planetary Science
Canadian institutionsMcMaster University
Fundersnot available
KeywordsMeteoritePlanetesimalChondriteMurchison meteoriteParent bodyAmino acidChemistryAstrobiologyAbundance (ecology)Carbonaceous chondriteAstrochemistryRelative species abundanceAstrophysicsPhysicsSolar SystemBiologyBiochemistryEcologyGalaxy

Abstract

fetched live from OpenAlex

Carbonaceous chondrite meteorites are known for having high water and organic material contents, including amino acids. Here we address the origin of amino acids in the warm interiors of their parent bodies (planetesimals) within a few million years of their formation, and connect this with the astrochemistry of their natal protostellar disks. We compute both the total amino acid abundance pattern as well as the relative frequencies of amino acids within the CM2 (e.g. Murchison) and CR2 chondrite subclasses based on Strecker reactions within these bodies. We match the relative frequencies to well within an order of magnitude among both CM2 and CR2 meteorites for parent body temperatures $<$ 200$^{\circ}$C. These temperatures agree with 3D models of young planetesimal interiors. We find theoretical abundances of approximately 7x10$^5$ parts-per-billion (ppb), which is in agreement with the average observed abundance in CR2 meteorites of 4$\pm$7x10$^5$, but an order of magnitude higher than the average observed abundance in CM2 meteorites of 2$\pm$2x10$^4$. We find that the production of hydroxy acids could be favoured over the production of amino acids within certain meteorite parent bodies (e.g. CI1, CM2) but not others (e.g. CR2). This could be due to the relatively lower NH$_3$ abundances within CI1 and CM2 meteorite parent bodies, which leads to less amino acid synthesis. We also find that the water content in planetesimals is likely to be the main cause of variance between carbonaceous chondrites of the same subclass. We propose that amino acid abundances are primarily dependent on the ammonia and water content of planetesimals that are formed in chemically distinct regions within their natal protostellar disks.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame distilled prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

metaresearch head score (Codex)0.001
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Observational · Consensus signal: Observational
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.276
Threshold uncertainty score0.348

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0010.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0010.000
Research integrity0.0000.001
Insufficient payload (model declined to judge)0.0000.000

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.023
GPT teacher head0.254
Teacher spread0.231 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one teacher head, not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designObservational
Domainnot available
GenreEmpirical

How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".

Quick stats

Citations18
Published2015
Admission routes1
Has abstractyes

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