DISCOVERY OF AN ∼23<i>M</i><sub>Jup</sub>BROWN DWARF ORBITING ∼700 AU FROM THE MASSIVE STAR HIP 78530 IN UPPER SCORPIUS
Bibliographic record
Abstract
We present the discovery of a substellar companion on a wide orbit around the ∼ 2.5 M ☉ star HIP 78530, which is a member of the 5 Myr old Upper Scorpius association. We have obtained follow-up imaging over two years and show that the companion and primary share common proper motion. We have also obtained JHK spectroscopy of the companion and confirm its low surface gravity, in accordance with the young age of the system. A comparison with Drift-Phoenix synthetic spectra indicates an effective temperature of 2800 ± 200 K and a comparison with template spectra of young and old dwarfs indicates a spectral type of M8 ± 1. The mass of the companion is estimated to be 19–26 M Jup based on its bolometric luminosity and the predictions of evolutionary models. The angular separation of the companion is 4 5, which at the distance of the primary star, 156.7 pc, corresponds to a projected separation of ∼710 AU. This companion features one of the lowest mass ratios (∼0.009) of any known companion at separations greater than 100 AU.
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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 | 0.000 | 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".