Possible anti-correlations between pulsation amplitudes and the disk growth of Be stars in giant-outbursting Be X-ray binaries
Abstract The mechanism of X-ray outbursts in Be X-ray binaries remains a mystery, and understanding their circumstellar disks is crucial for a solution of the mass-transfer problem. In particular, it is important to identify the Be star activities (e.g., pulsations) that cause mass ejection and, hence, disk formation. Therefore, we investigated the relationship between optical flux oscillations and the infrared (IR) excess in a sample of five Be X-ray binaries. Applying the Lomb-Scargle technique to high-cadence optical light curves from the Transiting Exoplanet Survey Satellite (TESS), we detected several significant oscillation modes in the 3 to 24 hour period range for each source. We also measured the IR excess (a proxy for disk growth) of those five sources, using J-band light curves from Palomar Gattini-IR. In four of the five sources, we found anti-correlations between the IR excess and the amplitude of the main flux oscillation modes. This result is inconsistent with the conventional idea that non-radial pulsations drive mass ejections. We propose an alternative scenario where internal temperature variations in the Be star cause transitions between pulsation-active and mass-ejection-active states.
Authors
- Roberto Soria (ORCID: https://orcid.org/0000-0002-4622-796X)
- Nicholas Earley (ORCID: https://orcid.org/0000-0001-6627-9903)
- Tony Travouillon (ORCID: https://orcid.org/0000-0001-9304-6718)
- Masafumi Niwano (ORCID: https://orcid.org/0000-0003-3102-7452)
- Ryan M. Lau (ORCID: https://orcid.org/0000-0003-0778-0321)
- Ichiro Takahashi (ORCID: https://orcid.org/0000-0003-2691-4444)
- Yoichi Yatsu (ORCID: https://orcid.org/0000-0003-1890-3913)
- Michael Fausnaugh (ORCID: https://orcid.org/0000-0002-9113-7162)
- G. Ricker (ORCID: https://orcid.org/0000-0003-2058-6662)
- Jamie Soon (ORCID: https://orcid.org/0000-0001-9226-4043)
- Mahito Sasada (ORCID: https://orcid.org/0000-0001-5946-9960)
- M. Hankins (ORCID: https://orcid.org/0000-0001-9315-8437)
- R. Vanderspek (ORCID: https://orcid.org/0000-0001-6763-6562)
- M. M. Kasliwal (ORCID: https://orcid.org/0000-0002-5619-4938)
- M. C. B. Ashley (ORCID: https://orcid.org/0000-0003-1412-2028)
- Nobuyuki Kawai
- Anna M Moore
- Kishalay De
Institutions
- Tokyo Institute of Technology (JP)
- Australian National University (AU)
- California Institute of Technology (US)
- Texas Tech University (US)
- The University of Sydney (AU)
- Chinese Academy of Sciences (CN)
- UNSW Sydney (AU)
- Kavli Institute for Particle Astrophysics and Cosmology (US)
- Osservatorio Astrofisico di Torino (IT)
- Community Science and Data Center (US)
- NSF NOIRLab (US)
- Arkansas Tech University (US)
Publication Details
- Journal
- Monthly Notices of the Royal Astronomical Society
- Published
- 2024-09-20
- DOI
- https://doi.org/10.1093/mnras/stae2160
- Primary Topic
- Astrophysical Phenomena and Observations
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- National Science Foundation
- Smithsonian Institution
- National Aeronautics and Space Administration
- Gordon and Betty Moore Foundation
- California Institute of Technology
- University of Washington
- Johns Hopkins University
- Space Telescope Science Institute
- European Space Agency
- Queen's University Belfast
- Queen's University
- Nuclear Safety and Security Commission
- National Central University
- Stockholms Universitet
- Eötvös Loránd Tudományegyetem
- Max-Planck-Institut für Astronomie
- Science Mission Directorate
- Science and Technology Facilities Council
- Deutsches Elektronen-Synchrotron
- Japan Society for the Promotion of Science
- Japan Aerospace Exploration Agency
- RIKEN
- Planetary Science Division
- Los Alamos National Laboratory