A new white dwarf companion around the Δμ star GJ 3346
Bibliographic record
Abstract
ABSTRACT We present the discovery of a white dwarf companion at ∼3.6 arcsec from GJ 3346, a nearby (π ∼ 42 mas) K star observed with SPHERE@VLT as part of an open time survey for faint companions to objects with significant proper motion discrepancies (Δμ) between Gaia DR1 and Tycho-2. Syrius-like systems like GJ 3346 AB, which include a main-sequence star and a white dwarf, can be difficult to detect because of the intrinsic faintness of the latter. They have, however, been found to be common contaminants for direct imaging (DI) searches. White dwarfs have in fact similar brightness to substellar companions in the infrared, while being much brighter in the visible bands like those used by Gaia. Combining our observations with Gaia DR2 and with several additional archival data sets, we were able to fully constrain the physical properties of GJ 3346 B, such as its effective temperature (11 × 103 ± 500 K) as well as the cooling age of the system (648 ± 58 Myr). This allowed us to better understand the system history and to partially explain the discrepancies previously noted in the age indicators for this object. Although further investigation is still needed, it seems that GJ 3346, which was previously classified as young, is in fact most likely to be older than 4 Gyr. Finally, given that the mass (0.58 ± 0.01 M⊙) and separation (85 au) of GJ 3346 B are compatible with the observed Δμ, this discovery represents a further confirmation of the potential of this kind of dynamical signatures as selection methods for DI surveys targeting faint, substellar companions.
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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 | 0.001 | 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".