The Optical Gravitational Lensing Experiment. OGLE #7: Binary Microlens or a New Unusual Variable?
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, , 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 -band coming from a non-lensed source.
Keywords
Cite
@article{arxiv.astro-ph/9407084,
title = {The Optical Gravitational Lensing Experiment. OGLE #7: Binary Microlens or a New Unusual Variable?},
author = {A. Udalski and M. Szymanski and S. Mao and R. Di Stefano and J. Kaluzny and M. Kubiak and M. Mateo and W. Krzeminski},
journal= {arXiv preprint arXiv:astro-ph/9407084},
year = {2009}
}
Comments
10 pages, 1 Table, 3 Figures; requires AAS LaTeX aaspp.sty macro. Submitted to Astrophysical Journal Letters. Paper and figures also available via anonymous ftp at ftp://sirius.astrouw.edu.pl/ogle/ogle7/