Characterization of the gaseous companion<i>κ</i>Andromedae b
Bibliographic record
Abstract
Context.We previously reported the direct detection of a low-mass companion at a projected separation of 55 ± 2 AU around the B9-type star κ Andromedae.The properties of the system (mass ratio, separation) make it a benchmark for understanding the formation and evolution of gas giant planets and brown dwarfs on wide orbits.Aims.We present new angular differential imaging (ADI) images of the system at 2.146 (K s ), 3.776 (L ), 4.052 (NB_4.05),and 4.78 µm (M ) obtained with Keck/NIRC2 and LBTI/LMIRCam, as well as more accurate near-infrared photometry of the star with the MIMIR instrument.We aim to determine the near-infrared spectral energy distribution of the companion and use it to characterize the object.Methods.We used analysis methods adapted to ADI to extract the companion flux.We compared the photometry of the object to reference young, and old objects and to a set of seven PHOENIX-based atmospheric models of cool objects accounting for the formation of dust.We used evolutionary models to derive mass estimates considering a wide range of plausible initial conditions.Finally, we used dedicated formation models to discuss the possible origin of the companion.Results.We derive a more accurate J = 15.86 ± 0.21, H = 14.95 ± 0.13, K s = 14.32 ± 0.09 mag for κ And b.We detect the companion in all our high-contrast observations.We confirm previous contrasts obtained at K s and L band.We derive NB_4.05 = 13.0 ± 0.2, and M = 13.3 ± 0.3 mag and estimate log 10 (L/L ) = -3.76± 0.06.Atmospheric models yield T eff = 1900 +100 -200 K.They do not set any constraint on the surface gravity."Hotstart" evolutionary models predict masses of 14 +25 -2 M Jup based on the luminosity and temperature estimates, and when considering a conservative age range for the system (30 +120 -10 Myr), "warm-start" evolutionary tracks constrain the mass to M ≥ 10 M Jup .Conclusions.The mass of κ Andromedae b mostly falls in the brown-dwarf regime, owing to remaining uncertainties in age and in mass-luminosity models.According to the formation models, disk instability in a primordial disk may account for the position and a wide range of plausible masses of κ And b.
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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 | 0.001 |
| Research integrity | 0.000 | 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".