The masses of PSR J1911–5958A and its white dwarf companion
Bibliographic record
Abstract
We present spectroscopic and photometric observations of the optical counterpart to PSR J1911-5958A, a millisecond pulsar located towards the globular cluster NGC 6752. We measure radial velocities from the spectra and determine the systemic radial velocity of the binary and the radial-velocity amplitude of the white-dwarf orbit. Combined with the pulsar orbit obtained from radio timing, we infer a mass ratio of . The spectrum of the counterpart is that of a hydrogen atmosphere, showing Balmer absorption lines up to H12, and we identify the counterpart as a helium-core white dwarf of spectral type DA5. Comparison of the spectra with hydrogen atmosphere models yield a temperature K and a surface gravity cgs. Using mass-radius relations appropriate for low-mass helium-core white dwarfs, we infer the white-dwarf mass and radius . Combined with the mass ratio, this constrains the pulsar mass to . If we instead use the white-dwarf spectrum and the distance of NGC 6752 to determine the white-dwarf radius, we find . For the observed temperature, the mass-radius relations predict a white-dwarf mass of , constraining the pulsar mass to . We find that the white-dwarf radius determined from the spectrum and the systemic radial velocity of the binary are only marginally consistent with the values that are expected if PSR J1911-5958A is associated with NGC 6752. We discuss possible causes to explain this inconsistency, but conclude that our observations do not conclusively confirm nor disprove the assocation of the pulsar binary with the globular cluster.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| 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".