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On the Stability of the 421-day Periodicity in A0538-66

Katherine E. McGowan·Phil A. Charles
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Abstract

In this paper we analyse 70 years of archival Harvard and Schmidt plate data of the 16.6 d Be X-ray binary A0538-66 in order to search for the presence of the long-term period of 420.82 +/- 0.79 d found in MACHO photometry (Alcock et al. 2001). We find evidence for a long-term period of 421.29 +/- 0.95 d in the archival data, and examine its stability. We also combine the archival and MACHO datasets in order to improve the accuracy of the orbital period determination, using a cycle-counting analysis to refine its value to 16.6460 +/- 0.0004 d. We also test the model proposed in our previous paper (Alcock et al. 2001) with observations documented in the literature for A0538-66 from 1980-1995, constraining the system inclination to be i > 74.9 +/- 6.5 deg.

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Katherine E. McGowan, Phil A. Charles. 2002-11-01. On the Stability of the 421-day Periodicity in A0538-66. https://doi.org/10.1046/j.1365-8711.2003.06220.x

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