Mass measurement of a single unseen star and planetary detection efficiency for OGLE 2007-BLG-050

V. Batista*, S. Dong, A. Gould, J. P. Beaulieu, A. Cassan, G. W. Christie, C. Han, A. Udalski, W. Allen, D. L. DePoy, A. Gal-Yam, B. S. Gaudi, B. Johnson, S. Kaspi, C. U. Lee, D. Maoz, J. McCormick, I. McGreer, B. Monard, T. NatuschE. Ofek, B.-G. Park, R. W. Pogge, D. Polishook, A. Shporer, M. D. Albrow, D. P. Bennett, S. Brillant, M. Bode, D. M. Bramich, M. Burgdorf, J. A. R. Caldwell, H. Calitz, A. Cole, K. H. Cook, Ch. Coutures, S. Dieters, M. Dominik, D. D. Prester, J. Donatowicz, P. Fouque, J. Greenhill, M. Hoffman, K. Horne, U. G. Jorgensen, N. Kains, S. Kane, D. Kubas, R. Martin, Y. Tsapras, μFUN Collaboration, PLANET RoboNet Collaboration, OGLE Collaboration, MOA Collaboration

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)

Abstract

Aims. We analyze OGLE-2007-BLG-050, a high magnification microlensing event (A similar to 432) whose peak occurred on 2 May, 2007, with pronounced finite-source and parallax effects. We compute planet detection efficiencies for this event in order to determine its sensitivity to the presence of planets around the lens star.

Methods. Both finite-source and parallax effects permit a measurement of the angular Einstein radius theta(E) = 0.48 +/- 0.01 mas and the parallax pi(E) = 0.12 +/- 0.03, leading to an estimate of the lens mass M = 0.50 +/- 0.14 M(circle dot) and its distance to the observer D(L) = 5.5 +/- 0.4 kpc. This is only the second determination of a reasonably precise (

Results. When computing planet detection efficiency, we did not find any planetary signature, i.e. none of the planetary configurations provides a Delta chi(2) improvement higher than 60, and our detection efficiency results reveal significant sensitivity to Neptune-mass planets, and to a lesser extent Earth-mass planets in some configurations. Indeed, Jupiter and Neptune-mass planets are excluded with a high confidence for a large projected separation range between the planet and the lens star, respectively [0.6-10] and [1.4-4] AU, and Earth-mass planets are excluded with a 10% confidence in the lensing zone, i.e. [1.8-3.1] AU.

Original languageEnglish
Pages (from-to)467-478
Number of pages12
JournalAstronomy & Astrophysics
Volume508
Issue number1
DOIs
Publication statusPublished - Dec 2009

Keywords

  • gravitational lensing
  • techniques: photometric
  • stars: individual: OGLE 2007-BLG-050
  • planetary systems
  • GRAVITATIONAL LENSING EXPERIMENT
  • PARALLAX MICROLENSING EVENT
  • LARGE-MAGELLANIC-CLOUD
  • HIGH-MAGNIFICATION
  • GALACTIC BULGE
  • EXTRASOLAR PLANETS
  • BROWN DWARF
  • THICK-DISK
  • COMPANIONS
  • PHOTOMETRY

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