Gravitational binary-lens events with prominent effects of lens orbital motion

H. Park, A. Udalski, C. Han, A. Gould, J. P. Beaulieu, Y. Tsapras, M. K. Szymański, M. Kubiak, I. Soszyński, G. Pietrzyński, R. Poleski, K. Ulaczyk, P. Pietrukowicz, S. Kozłowski, J. Skowron, Wyrzykowski, J. Y. Choi, D. L. Depoy, Subo Dong, B. S. GaudiK. H. Hwang, Y. K. Jung, A. Kavka, C. U. Lee, L. A.G. Monard, B. G. Park, R. W. Pogge, I. Porritt, I. G. Shin, J. C. Yee, M. D. Albrow, D. P. Bennett, J. A.R. Caldwell, A. Cassan, C. Coutures, D. Dominis, J. Donatowicz, P. Fouqué, J. Greenhill, M. Huber, U. G. Jørgensen, S. Kane, D. Kubas, J. B. Marquette, J. Menzies, C. Pitrou, K. R. Pollard, K. C. Sahu, J. Wambsganss, A. Williams, M. Zub, A. Allan, D. M. Bramich, P. Browne, M. Dominik, K. Horne, M. Hundertmark, N. Kains, C. Snodgrass, I. A. Steele, R. A. Street

Research output: Contribution to journalArticle

24 Citations (Scopus)


Gravitational microlensing events produced by lenses composed of binary masses are important because they provide a major channel for determining physical parameters of lenses. In this work, we analyze the light curves of two binary-lens events, OGLE-2006-BLG-277 and OGLE-2012-BLG-0031, for which the light curves exhibit strong deviations from standard models. From modeling considering various second-order effects, we find that the deviations are mostly explained by the effect of the lens orbital motion. We also find that lens parallax effects can mimic orbital effects to some extent. This implies that modeling light curves of binary-lens events not considering orbital effects can result in lens parallaxes that are substantially different from actual values and thus wrong determinations of physical lens parameters. This demonstrates the importance of routine consideration of orbital effects in interpreting light curves of binary-lens events. It is found that the lens of OGLE-2006-BLG-277 is a binary composed of a low-mass star and a brown dwarf companion.

Original languageEnglish
Article number134
JournalAstrophysical Journal
Issue number2
Publication statusPublished - 1 Dec 2013
Externally publishedYes


  • binaries: general
  • gravitational lensing: micro
  • planets and satellites: general

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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    Park, H., Udalski, A., Han, C., Gould, A., Beaulieu, J. P., Tsapras, Y., Szymański, M. K., Kubiak, M., Soszyński, I., Pietrzyński, G., Poleski, R., Ulaczyk, K., Pietrukowicz, P., Kozłowski, S., Skowron, J., Wyrzykowski, Choi, J. Y., Depoy, D. L., Dong, S., ... Street, R. A. (2013). Gravitational binary-lens events with prominent effects of lens orbital motion. Astrophysical Journal, 778(2), [134].