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Record W2095711413 · doi:10.1051/0004-6361:20010098

Properties of OH/IR stars with IRAS LRS spectra

2001· article· en· W2095711413 on OpenAlexaff
Pisin Chen, R. Szczerba, Sun Kwok, Kevin Volk

Bibliographic record

VenueAstronomy and Astrophysics · 2001
Typearticle
Languageen
FieldPhysics and Astronomy
TopicStellar, planetary, and galactic studies
Canadian institutionsUniversity of Calgary
FundersNational Natural Science Foundation of China
KeywordsAstrophysicsPhysicsMaserStarsSilicateCarbon starSpectral lineLine (geometry)Stellar classificationAbsorption (acoustics)InfraredEmission spectrumAstronomyOptics

Abstract

fetched live from OpenAlex

1858 OH satellite line (1612 MHz) maser sources associated with the IRAS counterparts were assembled from the literature. Cross-correlation between collected OH/IR -IRAS sources and the recent catalogue of the IRAS LRS spectra (Kwok et al. [CITE]) allows us to subdivide 1024 of them (after excluding OH sources with uncertain IRAS associations) into 10 groups according to the Volk & Cohen ([CITE]) classification scheme. We have found that sources with silicate emission form the largest group (about 57% ), followed by the group with silicate absorption (only about 16% ). For more sensitive individual OH maser surveys these numbers differentiate even more and the ratio between silicate emission and absorption sources reaches a value close to 6. Surprisingly, we found an association of OH maser emission with a small number of stars with carbon-rich atmospheres. The distribution of these subgroups of OH/IR stars in the IRAS colour-colour and the period-colour diagrams as well as histograms of some physical properties are presented. The galactic distribution of important parameters (periods, IRAS colours, expansion and stellar velocities) for different classes of OH/IR sources is analyzed from the point of view of the stars' evolutionary status. The correlations among the periods, colours, expansion and star velocities and the pumping efficiencies for selected subgroups of OH/IR stars are also investigated. These analyses allow us to demonstrate that a significant fraction of silicate emission group sources do not form an evolutionary sequence with the silicate absorption objects -as is suggested e.g. by the IRAS colour-colour diagram, but rather form a lower initial mass sequence, i.e. these sources will never develop sufficient mass loss to manifest silicate absorption.

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 machine prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.002
Version: metacan-v3-hybrid-931329e0061cValidation 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 score0.003
Threshold uncertainty score0.007

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0000.002
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0030.002
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0020.001

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 head0.010
GPT teacher head0.183
Teacher spread0.173 · 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 source (direct Gemma or distilled Codex), 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

Citations46
Published2001
Admission routes1
Has abstractyes

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