PSR J1740-3052 - a pulsar with a massive companion
Bibliographic record
Abstract
We report on the discovery of a binary pulsar, PSR J1740-3052, during the Parkes multibeam pulsar survey. The pulsar has a spin period of 570 ms and is in a 231-day, highly eccentric orbit with a companion whose mass exceeds 11 M_sun. An accurate position for the pulsar was obtained using the Australia Telescope Compact Array. Timing observations at Jodrell Bank and Parkes show that the pulsar is young, having a characteristic age of 350 kyr, and unrecycled. Dual-frequency radio observations of the pulsar near periastron passage suggest that the dispersion measure and polarisation vary slightly but significantly during the orbit. These variations suggest a non-degenerate companion with a magnetized stellar wind. No significant X-ray emission was found in an archival ASCA observation two weeks after periastron passage. Near-infrared 2.2-um observations at the Siding Spring Observatory 2.3-m telescope and the 3.9-m Anglo-Australian Telescope reveal a late-type star coincident with the pulsar position. However, we do not believe that this star is the pulsar's companion, because a typical star of this mass and spectral type would extend beyond the pulsar's orbit. Furthermore, the measured advance of periastron of the pulsar is not significantly larger than that expected for a compact companion in general relativity, arguing for a main-sequence companion with radius only a few times that of the sun. Finally, the small dispersion measure variations are also consistent with a main-sequence companion, but inconsistent with the large mass-loss rates expected for a late-type supergiant. Although we cannot conclusively rule out a black-hole companion, we believe the true companion is most likely a main-sequence B star hidden by the light of the unassociated late-type star.
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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) | 0.001 | 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".