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Title: MOA-2008-BLG-379Lb: A massive planet from a high magnification event with a faint source

We report on the analysis of the high microlensing event MOA-2008-BLG-379, which has a strong microlensing anomaly at its peak due to a massive planet with a mass ratio of q = 6.9 × 10{sup –3}. Because the faint source star crosses the large resonant caustic, the planetary signal dominates the light curve. This is unusual for planetary microlensing events, and as a result, the planetary nature of this light curve was not immediately noticed. The planetary nature of the event was found when the Microlensing Observations in Astrophysics (MOA) Collaboration conducted a systematic study of binary microlensing events previously identified by the MOA alert system. We have conducted a Bayesian analysis based on a standard Galactic model to estimate the physical parameters of the lens system. This yields a host star mass of M{sub L}=3.3{sub −1.2}{sup +1.7} M{sub ⊙} orbited by a planet of mass m{sub P}=0.56{sub −0.27}{sup +0.24} M{sub Jup} at an orbital separation of a=3.3{sub −1.2}{sup +1.3} AU at a distance of D{sub L}=4.1{sub −1.9}{sup +1.7} kpc. The faint source magnitude of I {sub S} = 21.30 and relatively high lens-source relative proper motion of μ{sub rel} = 7.6 ± 1.6 mas yr{sup –1} imply that highmore » angular resolution adaptive optics or Hubble Space Telescope observations are likely to be able to detect the source star, which would determine the masses and distance of the planet and its host star.« less
Authors:
; ; ;  [1] ;  [2] ;  [3] ; ;  [4] ; ; ; ; ;  [5] ; ; ;  [6] ;  [7] ;  [8] ;  [9] ;  [10] more »; ; ; « less
  1. Department of Earth and Space Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043 (Japan)
  2. Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland)
  3. Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States)
  4. Institute of Information and Mathematical Sciences, Massey University, Private Bag 102-904, North Shore Mail Centre, Auckland (New Zealand)
  5. Solar-Terrestrial Environment Laboratory, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi 464-8601 (Japan)
  6. Department of Physics, University of Auckland, Private Bag 92019, Auckland (New Zealand)
  7. Okayama Astrophysical Observatory, National Astronomical Observatory, 3037-5 Honjo, Kamogata, Asakuchi, Okayama 719-0232 (Japan)
  8. Department of Physics, Konan University, Nishiokamoto 8-9-1, Kobe 658-8501 (Japan)
  9. Nagano National College of Technology, Nagano 381-8550 (Japan)
  10. Tokyo Metropolitan College of Industrial Technology, Tokyo 116-8523 (Japan)
Publication Date:
OSTI Identifier:
22348572
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 780; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTROPHYSICS; GRAVITATIONAL LENSES; MASS; ORBITS; PLANETS; PROPER MOTION; RESOLUTION; SPACE; STARS; TELESCOPES; VISIBLE RADIATION