Discovery of the Second Y+Y Dwarf Binary System: CWISEP J193518.59-154620.3
Bibliographic record
Abstract
Abstract We present the discovery of a companion to the Y dwarf, CWISEP J193518.59–154620.3, the second Y-Y dwarf binary detected to date. Y dwarfs are the coldest known free-floating objects (<500 K) and, on average, represent the lowest mass objects directly formed through turbulent fragmentation of a molecular cloud. Studying their multiplicity allows us to place strong constraints on the ability to form multiple systems of planetary masses and approach the opacity limit of fragmentation. Due to their physical properties, Y dwarfs also serve as analogs to gas giant planets. CWISEP J193518.59–154620.3 has been shown to have a unique methane emission feature in its near-infrared spectrum at 3.326 μ m, potentially indicative of auroral processes without a clear origin. CWISEP J193518.59–154620.3 was observed with JWST’s MIRI in the F1000W, F1280W, and F1800W filters. We applied a point-spread function (PSF) fitting algorithm using empirically derived PSF models and resolved a companion in the F1000W and F1280W filters separated by 172 mas and 2.48 au, assuming a distance of 14.43 pc. Using the ATMO2020 evolutionary models, we estimate a mass of 12–39 M Jup for the primary and 7–24 M Jup for the companion, assuming an age of 1–10 Gyr for a mass ratio of 0.55–0.62, resulting in an estimated period of 16–28 yr. It is unknown which component of this binary exhibits the methane emission feature. We also resolve known companions WISE J014656.66+423410.0B and WISE J171104.60+350036.8B using MIRI data and present their F1000W and F1280W photometry.
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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 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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.
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".