OGLE-BLAP-001 and ZGP-BLAP-08: two possible magnetic blue large-amplitude pulsators
arXiv:2410.19093 · doi:10.1051/0004-6361/202451631
Abstract
Blue large-amplitude pulsators (BLAPs) are a newly discovered group of compact pulsating stars whose origin needs to be explained. Of the existing evolutionary scenarios that could lead to the formation of BLAPs, there are two in which BLAPs are the products of the merger of two stars, either a main sequence star and a helium white dwarf or two low-mass helium white dwarfs. Among over a hundred known BLAPs, three equidistant in frequency modes had been found in one, OGLE-BLAP-001. We show that similar three equidistant in frequency modes exist in yet another BLAP, ZGP-BLAP-08. This perfect separation in frequency is a strong argument to explain the modes in terms of an oblique pulsator model. This model is supported by the character of the changes of the pulsation amplitude and phase with the rotational phase. Consequently, we hypothesize that these two BLAPs are magnetic, as equidistant in frequency pulsation modes should be observed in the presence of a magnetic field whose axis of symmetry does not coincide with the rotation axis. A logical consequence of this hypothesis is to postulate that these two BLAPs could have originated in a merger scenario, just how the origin of magnetic white dwarfs is explained. We also find that period changes in both stars cannot be interpreted by a constant rate of period change and discuss the possible origin of these changes.
13 pages, 11 figures, 2 tables, accepted for publication in A&A
References in corpus (24)
- The Transiting Exoplanet Survey Satellite
- The Zwicky Transient Facility: System Overview, Performance, and First Results
- The Zwicky Transient Facility: Data Processing, Products, and Archive
- Achieving better than 1 minute accuracy in the Heliocentric and Barycentric Julian Dates
- The Zwicky Transient Facility Catalog of Periodic Variable Stars
- How mergers magnetise massive stars
- Gaia Data Release 3. Summary of the variability processing and analysis
- Magnetic fields in isolated and interacting white dwarfs
- Stellar mergers as the origin of the blue main-sequence band in young star clusters
- Blue large-amplitude pulsators as a new class of variable stars
- Magnetic Field Generation in Stars
- Merging Binary Stars and the magnetic white dwarfs
- A massive helium star with a sufficiently strong magnetic field to form a magnetar
- A magnetic massive star has experienced a stellar merger
- TESS Cycle 1 observations of roAp stars with 2-min cadence data
- Pulsation in faint blue stars
- HD 24355 observed by the Kepler K2 mission: A rapidly oscillating Ap star pulsating in a distorted quadrupole mode
- Binary evolution pathways of Blue Large-Amplitude Pulsators
- Shell helium-burning hot subdwarf B stars as candidates for blue large-amplitude pulsators
- HD 133729: A blue large-amplitude pulsator in orbit around a main-sequence B-type star
- Identifying Blue Large Amplitude Pulsators from Gaia DR2 & ZTF DR3
- The OmegaWhite Survey for Short-Period Variable Stars VII: High amplitude, short period blue variables
- Large-scale ordered magnetic fields generated in mergers of helium white dwarfs
- Discovery of multiple p-mode pulsation frequencies in the roAp star, HD 86181