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Record W2064948947 · doi:10.1086/323943

The Spectra of Young Protostars of Cepheus A

2001· article· en· W2064948947 on OpenAlexaff
V. A. Hughes

Bibliographic record

VenueThe Astrophysical Journal · 2001
Typearticle
Languageen
FieldPhysics and Astronomy
TopicAstrophysics and Star Formation Studies
Canadian institutionsQueen's University
Fundersnot available
KeywordsPhysicsProtostarAstrophysicsSpectral lineOutflowFlux (metallurgy)IonizationJet (fluid)AstronomyStarsStar formationIon

Abstract

fetched live from OpenAlex

Radio data obtained over more than 13 years of monitoring give detailed spectra of the youngest known protostars in the young star formation region Cepheus A. Two sources, namely HW 2 and HW 3(d), increase in flux density from 15 to 43 GHz, as previously known. The data confirm that HW 2 appears to be thermal, producing two ionized jets, and these jets show an averaged separation speed of 95 km s -1 , in comparison with the difference in the red and blue HCO + outflow velocities of 54 km s -1 . The jets appear to be acting as pistons to produce the molecular outflows. HW 3(c) has time-dependent spectra which decrease between 1.4 and 4.9 GHz, rise to a peak near to 15 GHz, and then fall rapidly to 43.3 GHz. The low-frequency emission appears to be synchrotron radiation from a jet, and the high-frequency emission indicates gyrosynchrotron radiation. HW 3(d) is somewhat similar at the lower frequencies but at the higher frequencies is doubly peaked. One component has a steeply rising spectrum, as for HW 2. HW 3(d) is similar to the double source of L1551 NW but is unlikely to be a double protostar. The data from the whole region, including previous analyses, show time-dependent events that are less than 1000 yr old. The events consist of variations in both flux density and spectra and involve high-energy electrons. These time-dependent variations, together with measured proper motions, indicate that extremely energetic events occur in protostars before they reach the Class 0 stage and could play an important part in dispersing the surrounding gas. Caution must be observed when interpreting processes in protostar-forming regions if they are observed only in the snapshot mode.

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)0.001
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 score0.002
Threshold uncertainty score0.004

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0000.001
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0010.001
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0010.000

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 head0.009
GPT teacher head0.236
Teacher spread0.228 · 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

Citations18
Published2001
Admission routes1
Has abstractyes

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