Polarimetric Variations of Binary Stars. V. Pre-Main-Sequence Spectroscopic Binaries Located in Ophiuchus and Scorpius
Bibliographic record
Abstract
We present polarimetric observations of seven pre–main-sequence (PMS) spectroscopic binaries located in the ρ Ophiuchus and Upper Scorpius star-forming regions (SFRs). The average observed polarizations at 7660 Å are between 0.5% and 3.5%. After estimates of the interstellar polarization are removed, all binaries have an intrinsic polarization above 0.4%, even though most of them do not present other evidences for circumstellar dust. Two binaries, NTTS 162814-2427 and NTTS 162819-2423S, present high levels of intrinsic polarization between 1.5% and 2.1%, in agreement with the fact that other observations (photometry, spectroscopy) indicate the presence of circumstellar dust. Tests reveal that all seven PMS binaries have a statistically variable or possibly variable polarization. Combining these results with our previous sample of binaries located in the Taurus, Auriga, and Orion SFRs, 68% of the binaries have an intrinsic polarization above 0.5%, and 90% of the binaries are polarimetrically variable or possibly variable. NTTS 160814-1857, 162814-2427, and 162819-2423S are clearly polarimetrically variable. The first two also exhibit phase-locked variations over ∼10 and ∼40 orbits, respectively. Statistically, NTTS 160905-1859 is possibly variable, but it shows periodic variations not detected by the statistical tests; those variations are not phased locked and only present for short intervals of time. The amplitudes of the variations reach a few tenths of a percent, greater than for the previously studied PMS binaries located in the Taurus, Orion, and Auriga SFRs. The high-eccentricity system NTTS 162814-2427 shows single-periodic variations, in agreement with our previous numerical simulations. We compare the observations with some of our numerical simulations and also show that an analysis of the periodic polarimetric variations with the Brown, McLean, & Emslie (BME) formalism to find the orbital inclination is for the moment premature: nonperiodic events introduce stochastic noise that partially masks the periodic variations and prevents the BME formalism from finding a reasonable estimate of the inclination.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot 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.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
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.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
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".