1998/03/20 by Lee Homer, L. Homer, P. A. Charles +2 · 1 citation
Earth and Planetary Sciences · Engineering · Physics and Astronomy · #Astronomical Observations and Instrumentation #Astrophysical Phenomena and Observations #High-pressure geophysics and materials #astro-ph
paper · pdf · doi:10.1046/j.1365-8711.1998.01656.x
7 pages, 4 figures, to be published in MNRAS
arxiv created 1998/03/20 · openalex publication_date 1998/08/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We report the discovery of a 2.1-h optical modulation in the transient source GS 1826–24, based on two independent, high-time-resolution photometric observing runs. There is additional irregular variability on shorter time-scales. The source also exhibited an optical burst during each observation, with peak fluxes consistent with those of the three X-ray bursts so far detected by BeppoSAX. We compare the low-amplitude variation (∼ 0.06 mag) to that seen on the orbital periods of the short-period X-ray bursters, X1636−536 and X1735−444, as well as the similarity in their non-periodic fluctuations. Other transient neutron star LMXBs possess short periods in the range 3.8–7.1 h. However, if confirmed as the orbital, a 2.1-h modulation would make GS 1826–24 unique and therefore of great interest within the context of LMXB formation and evolution.