The Planetary Mass Companion 2MASS 1207−3932B: Temperature, Mass, and Evidence for an Edge‐on Disk
Bibliographic record
Abstract
We present J -band imaging and H + K -band low-resolution spectroscopy of 2MASS 1207-3932AB, obtained with VLT NACO. For the putative planetary mass secondary, we find J = 20.0 ± 0.2 mag. The HK spectra of both components imply low gravity and a dusty atmosphere for the secondary. Comparisons to synthetic spectra yield T eff,A ≈ 2550 ± 150 K and T eff,B ≈ 1600 ± 100 K, consistent with their late-M and mid- to late-L types. For these T eff and an age of 5-10 Myr, evolutionary models imply M A ≈ 24 ± 6 M Jup and M B ≈ 8 ± 2 M Jup . Independent comparisons of these models to the observed colors, spanning ~ I to L ', also yield the same masses and temperatures. Our primary mass agrees with other recent analyses; however, our secondary mass, while still in the planetary regime, is 2-3 times larger than claimed previously. This discrepancy can be traced to the luminosities: while the absolute photometry and M bol of the primary agree with theoretical predictions, the secondary is ~2.5 ± 0.5 mag fainter than expected in all bands from I to L ' and in M bol . This accounts for the much lower secondary mass (and temperature) derived earlier. We argue that this effect is highly unlikely to result from a variety of model-related problems and is instead real. This conclusion is bolstered by the absence of any luminosity problems in either the primary or AB Pic B, which we also analyze. We therefore suggest gray extinction in 2M1207B, due to occlusion by an edge-on circumsecondary disk. This is consistent with the observed properties of edge-on disks around T Tauri stars and with the known presence of a high-inclination evolved disk around the primary. Finally, the system's implied mass ratio of ~0.3 suggests a binary-like formation scenario.
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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 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 0.002 |
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".