Hokupa'a-Gemini Discovery of Two Ultracool \n Companions to the Young Star HD 130948
Bibliographic record
Abstract
We report the discovery of two faint ultracool \n companions to the nearby (d~17.9 pc) young G2 V \n star HD 130948 (HR 5534, HIP 72567) using the \n Hokupa'a adaptive optics (AO) instrument mounted \n on the Gemini North 8 m telescope. Both objects \n have the same common proper motion as the \n primary star as seen over a 7 month baseline and \n have near-IR photometric colors that are \n consistent with an early L classification. \n Near-IR spectra taken with the NIRSPEC AO \n instrument on the Keck II telescope reveal K I \n lines, FeH, and H2O band heads. Based \n on these spectra, we determine that both objects \n have a spectral type of dL2 with an uncertainty \n of two spectral subclasses. The position of the \n new companions on the H-R diagram in comparison \n with theoretical models is consistent with the \n young age of the primary star (<0.8 Gyr) \n estimated on the basis of X-ray activity, lithium \n abundance, and fast rotation. HD 130948B and C \n likely constitute a pair of young contracting \n brown dwarfs with an orbital period of about 10 \n yr and will yield dynamical masses for L dwarfs \n in the near future. Based on observations \n obtained at the Gemini Observatory, which is \n operated by the Association of Universities for \n Research in Astronomy, Inc., under a cooperative \n agreement with the NSF on behalf of the Gemini \n partnership: the National Science Foundation \n (US), the Particle Physics and Astronomy Research \n Council (UK), the National Research Council \n (Canada), CONICYT (Chile), the Australian \n Research Council (Australia), CNPq (Brazil), and \n CONICET (Argentina).
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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 | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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".