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arXiv · astro-ph/9407084

The Optical Gravitational Lensing Experiment. OGLE #7: Binary Microlens or a New Unusual Variable?

A. Udalski·M. Szymanski·S. Mao·R. Di Stefano·J. Kaluzny·M. Kubiak·M. Mateo·W. Krzeminski
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Abstract

We present the light curve of an unusual variable object, OGLE #7, detected during the OGLE search for microlensing events. After one season of being in a low, normal state, the star brightened by more than 2~mag with a characteristic double-maximum shape, and returned to normal brightness after 60 days. We consider possible explanations of the photometric behavior of OGLE #7. The binary microlens model seems to be the most likely explanation -- it reproduces well the observed light curve and explains the observed colors of OGLE #7. The characteristic time scale of the OGLE #7 event, $t_E$, is equal to 80 days, the longest observed to date. The binary microlens model predicts that the spectrum of the star should be composite, with roughly 50% of its light in the $I$-band coming from a non-lensed source.

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A. Udalski, M. Szymanski, S. Mao, R. Di Stefano, J. Kaluzny, M. Kubiak, M. Mateo, W. Krzeminski. 1994-07-26. The Optical Gravitational Lensing Experiment. OGLE #7: Binary Microlens or a New Unusual Variable?. https://doi.org/10.1086/187643

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