Plaskett's Star: an examination of the TESS photometric data
Bibliographic record
Abstract
HD 47129 (“Plaskett's Star”) is an O+O spectroscopic binary reported by Linder et al to have a short orbital period of approximately 14.4 d. Grunhut et al. (2013) reported the secondary component of this star to be strongly magnetic and follow up work (Grunhut et al., in prep.) determined the secondary star's rotational period to be 1.21551 d through magnetic modulation. This system is particularly significant because it is the only known close binary containing a magnetic O-type star. Furthermore, the rapid rotation of the magnetic star suggests there exists some mechanism that has rejuvenated the star's angular momentum. It has been proposed that past mass transfer may be responsible for this, raising questions about mass transfer as the origin of its magnetic field and suggesting a connection to stellar mergers as the origin for some magnetic fields. The TESS satellite observed this system from Dec 15, 2018 to Jan 6, 2019, providing new high-cadence, high-precision photometry for this system. To analyze this new data, we have developed a robust prewhitening method employing a two-stage routine for simultaneously fitting many frequencies. In addition to the new TESS data, we examined the archival CoRoT photometry (first analyzed by Mahy et al. 2011). These datasets are both roughly 1 month in length with comparable precision and were acquired 10 years apart. We analyzed both datasets independently as well as in tandem. Both datasets reveal the presence of strong modulation consistent with the rotation period of the magnetic star and its first harmonic as well as the weaker presence of several higher harmonics. The CoRoT dataset also exhibits modulation at the orbital period of the system and its harmonic. Individual analysis yields strong variability at 0.623, 0.286, 0.125, and 0.696 c/d for the TESS timeseries and 0.369, 0.648, and 0.146 c/d for the CoRoT timeseries. Finally, a combined analysis of the datasets demonstrates that the principal modulation at 1.645 c/d is stable over the 10 years separating the datasets. Ongoing work involves understanding the origin of the non-rotational non-orbital frequencies, evaluating their stability, and leveraging these results to better understand the properties and evolutionary history of the system
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.004 | 0.004 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| 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".