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2010 Fiscal Year Final Research Report

Search for Extra-solar Planet and Dark Stars by Gravitational Microlensing

Research Project

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Project/Area Number 19340058
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Research Field Particle/Nuclear/Cosmic ray/Astro physics
Research InstitutionKonan University

Principal Investigator

MURAKI Yasushi  Konan University, 理工学部, 教授 (70013430)

Co-Investigator(Kenkyū-buntansha) SUMI Takahiro  名古屋大学, 太陽地球環境研究所, 助教 (30432214)
SAKO Takashi  名古屋大学, 太陽地球環境研究所, 助教 (90324368)
Co-Investigator(Renkei-kenkyūsha) ABE Fumio  名古屋大学, 太陽地球環境研究所, 准教授 (80184224)
Project Period (FY) 2007 – 2010
Keywords重力レンズ効果 / ダークマター / 太陽系外惑星 / 暗黒天体 / 暗天体 / 変光星
Research Abstract

The Japan-NZ astronomy collaboration known as MOA (Microlensing Observations in Astrophysics) was formed in 1995 with the aim of searching for a component of dark matter in the form of MACHOs (Massive Compact Halo Objects) and also for extra-solar planets using the gravitational microlensing technique. This technique uses the gravitational fields of stars and other massive objects to effectively form large lenses in space as predicted by general relativity. The feasibility of the microlensing technique was pointed out by Bohdan Paczynski in 1986. He proposed monitoring as many stars as possible in the Magellanic Clouds and the galactic bulge to find gravitational lenses in the galactic halo or the galactic disc.
The MOA collaboration commenced observations in 1995 using a 0.6m telescope at the Mt John observatory in NZ. In 2005 a 1.8m telescope was installed at Mt John by Japan. Since that time more than 500 microlensing events have been found each year towards the galactic bulge. Also, … More events have been found towards the Magellanic Clouds.
The events found by MOA were made publicly available via the world wide web to enable other observatories to monitor selected events, in particular those with high magnifications. This resulted in the discovery of 16 extra-solar planets orbiting stars in the galactic disc and the galactic bulge. These planets were found just beyond the snowlines of their host stars. This is the region of maximum sensitivity of the microlensing technique, and it also the region where ice-giant and gas-giant planets form according to the core accretion theory. The data on these planets complements data being obtained on closer-in planets by the radial velocity and transit techniques.
In addition to the above discoveries, a new class of extra-solar planets was discovered by MOA. These planets are not bound to stars. They have masses similar to that of Jupiter, and they are approximately as abundant as stars in the galaxy.
Finally, the Konan University group of MOA completed the analysis of observations made between 1999 and 2005 towards the Large Magellanic Cloud with the 0.6m telescope at Mt John. Approximately 9,000 Miras and 13,000 Cepheid variable stars were found. Those results will be presented in elsewhere. Less

  • Research Products

    (27 results)

All 2011 2010 2009 2008 Other

All Journal Article (21 results) (of which Peer Reviewed: 21 results) Presentation (5 results) Remarks (1 results)

  • [Journal Article] Unbound or Distant Planetary Mass Population detected by Gravitational Lensing2011

    • Author(s)
      Sumi T., Muraki Y., Sako T., et al.
    • Journal Title

      Nature Volume 473

      Pages: 349-352

    • Peer Reviewed
  • [Journal Article] Binary microlensing event OGLE-2009-BLG-020 gives a verifiable mass2011

    • Author(s)
      Skowron J., Muraki Y., Sumi T., Sako T., et al.
    • Journal Title

      distance and orbit predictions (in pres)

      Pages: arXiv:1101.3312

    • Peer Reviewed
  • [Journal Article] Measurements of Transit Timing Variations for WASP-5b2011

    • Author(s)
      Fukui A., Muraki Y., Sumi T., Sako T., et al.
    • Journal Title

      PASJ Volume 63

      Pages: 287-300

    • Peer Reviewed
  • [Journal Article] A sub-Saturn Mass Planet, MOA-2009-BLG-319Lb2011

    • Author(s)
      Miyake N., Muraki Y., Sumi T., Sako T., et al.
    • Journal Title

      The Astrophysical Journal Volume 728

      Pages: 120-130

    • Peer Reviewed
  • [Journal Article] A Cold Neptune-Mass Planet OGLE-2007-BLG-368Lb : Cold Neptunes Are Common2010

    • Author(s)
      Sumi T., Muraki Y., Sako T., et al.
    • Journal Title

      The Astrophysical Journal Volume 710, Issue 2

      Pages: 1641-1653

    • Peer Reviewed
  • [Journal Article] Sub-Saturn Planet MOA-2008-BLG-310Lb : Likely to be in the Galactic Bulge2010

    • Author(s)
      Janczak J., Muraki Y., Sumi T., Sako T., et al.
    • Journal Title

      The Astrophysical Journal Volume 711, Issue 2

      Pages: 731-743

    • Peer Reviewed
  • [Journal Article] Masses and Orbital Constraints for the OGLE 2006-BLG-109Lb,c Jupiter/Saturn Analog Planetary System2010

    • Author(s)
      Bennett D. P., Muraki Y., Sumi T., Sako T., et al.
    • Journal Title

      The Astrophysical Journal Volume 713, Issue 2

      Pages: 837-855

    • Peer Reviewed
  • [Journal Article] OGLE 2008-BLG-290 : an accurate measurement of the limb darkening of a galactic bulge K Giant spatially resolved by microlensing2010

    • Author(s)
      Fouque P., Muraki Y., Sumi T., Sako T., et al.
    • Journal Title

      Astronomy and Astrophysics Volume 518, id.Article

      Pages: 51

    • Peer Reviewed
  • [Journal Article] Determining the Physical Lens Parameters of the Binary Gravitational Microlensing Event MOA-2009-BLG-0162010

    • Author(s)
      Hwang K.-H., Muraki Y., Sumi T., Sako T., et al.
    • Journal Title

      The Astrophysical Journal Volume 717, Issue 1

      Pages: 435-440

    • Peer Reviewed
  • [Journal Article] Frequency of Solar-like Systems and of Ice and Gas Giants Beyond the Snow Line from High-magnification Microlensing Events in 2005-20082010

    • Author(s)
      Gould A., Muraki Y., Sumi T., Sako T., et al.
    • Journal Title

      The Astrophysical Journal Volume 720, Issue 2

      Pages: 1073-1089

    • Peer Reviewed
  • [Journal Article] OGLE-2009-BLG-092/MOA-2009-BLG-137 : A Dramatic Repeating Event with the Second Perturbation Predicted by Real-time Analysis2010

    • Author(s)
      Ryu Y.-H., Muraki Y., Sumi T., Sako T., et al.
    • Journal Title

      The Astrophysical Journal Volume 723, Issue 1

      Pages: 81-88

    • Peer Reviewed
  • [Journal Article] OGLE-2005-BLG-153: Microlensing Discovery and Characterization of a Very Low Mass Binary2010

    • Author(s)
      Hwang K.-H., Muraki Y., Sumi T., Sako T., et al.
    • Journal Title

      The Astrophysical Journal Volume 723, Issue 1

      Pages: 797-802

    • Peer Reviewed
  • [Journal Article] OGLE-2005-BLG-071Lb, the Most Massive M Dwarf Planetary Companion?2009

    • Author(s)
      Dong S., Muraki Y., Sumi T., Sako T., et al.
    • Journal Title

      The Astrophysical Journal Volume 695, Issue 2

      Pages: 970-987

    • Peer Reviewed
  • [Journal Article] Microlensing Event MOA-2007-BLG-400 : Exhuming the Buried Signature of a Cool, Jovian-Mass Planet2009

    • Author(s)
      Dong S., Muraki Y., Sumi T., Sako T., et al.
    • Journal Title

      The Astrophysical Journal Volume 698, Issue 2

      Pages: 1826-1837

    • Peer Reviewed
  • [Journal Article] The Extreme Microlensing Event OGLE-2007-BLG-224 : Terrestrial Parallax Observation of a Thick-Disk Brown Dwarf2009

    • Author(s)
      Gould A., Muraki Y., Sumi T., Sako T., et al.
    • Journal Title

      The Astrophysical Journal Letters, Volume 698, Issue 2

      Pages: L147-L151

    • Peer Reviewed
  • [Journal Article] Extreme Magnification Microlensing Event OGLE-2008-BLG-279 : Strong Limits on Planetary Companions to the Lens Star2009

    • Author(s)
      Yee J. C., Muraki Y., Sumi T., Sako T., et al.
    • Journal Title

      The Astrophysical Journal Volume 703, Issue 2

      Pages: 2082-2090

    • Peer Reviewed
  • [Journal Article] Interpretation of Strong Short-Term Central Perturbations in the Light Curves of Moderate Magnification Microlensing Events2009

    • Author(s)
      Han C., Muraki Y., Sumi T., Sako T., et al.
    • Journal Title

      The Astrophysical Journal Volume 705, issue2

      Pages: 1116-1121

    • Peer Reviewed
  • [Journal Article] Mass measurement of a single unseen star and planetary detection efficiency for OGLE 2007-BLG-0502009

    • Author(s)
      Batista V., Muraki Y., Sumi T., Sako T., et al.
    • Journal Title

      Astronomy and Astrophysics Volume 508, Issue 1

      Pages: 467-478

    • Peer Reviewed
  • [Journal Article] A Low-Mass Planet with a Possible Sub-Stellar-Mass Host in Microlensing Event MOA-2007-BLG-1922008

    • Author(s)
      Bennett D. P., Muraki Y., Sumi T., Sako T., et al.
    • Journal Title

      The Astrophysical Journal Volume 684, Issue 1

      Pages: 663-683

    • Peer Reviewed
  • [Journal Article] MOA-cam3 : a wide-field mosaic CCD camera for a gravitational microlensing survey in New Zealand2008

    • Author(s)
      Sako T., Muraki Y., Sumi T., et al.
    • Journal Title

      Experimental Astronomy Volume 22, Issue 1-2

      Pages: 51-66

    • Peer Reviewed
  • [Journal Article] Discovery of a Jupiter/Saturn Analog with Gravitational Microlensing2008

    • Author(s)
      Gaudi B.S, Muraki Y., Sumi T, Sako T, et al
    • Journal Title

      Science Volume 319

      Pages: 927-932

    • Peer Reviewed
  • [Presentation] MOA II observation in 2009 season2010

    • Author(s)
      Sumi T.
    • Organizer
      14^<th> workshop on gravitational microlensing
    • Place of Presentation
      Auckland
    • Year and Date
      20100100
  • [Presentation] MOAグループMOA-I 望遠鏡によるLMC観測データの変光天体データ2010

    • Author(s)
      和田幸平、村木綏、竹内峯, 他
    • Organizer
      2010年秋季 天文学会
    • Place of Presentation
      金沢大学
    • Year and Date
      2010-09-22
  • [Presentation] MOAグループMOA I望遠鏡観測によるLMC領域の変光天体データベース2010

    • Author(s)
      和田幸平、村木 綏、竹内峯, 他
    • Organizer
      2010年秋季 物理学会
    • Place of Presentation
      九州工業大学
    • Year and Date
      2010-09-12
  • [Presentation] Planetary microlensing event OGLE 2007-BLG-3682009

    • Author(s)
      Sumi T.
    • Organizer
      13^<th> Microlensing workshop
    • Place of Presentation
      Paris
    • Year and Date
      20090100
  • [Presentation] MOA-II microlensing survey2008

    • Author(s)
      Sumi T.
    • Organizer
      Manchester microlensing conference
    • Place of Presentation
      Manchester
    • Year and Date
      20080100
  • [Remarks] ホームページ等

    • URL

      http://www.phys.canterbury.ac.nz/moa/publications.html

URL: 

Published: 2012-01-26   Modified: 2016-04-21  

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