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5 - Microlensing

Published online by Cambridge University Press:  01 June 2011

Michael Perryman
Affiliation:
Max-Planck-Institut für Astronomie, Heidelberg
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Summary

By the end of 2010, eleven exoplanets in ten systems had been discovered through gravitational microlensing (Table 5.1). The first unambiguous detection of a 4MJ planet with a projected separation of ∼4 AU was reported in 2004, and the discovery of a 5Moplus; planet in 2006. With the characterisation of a two-planet system somewhat analogous to Jupiter and Saturn in 2008, in which the orbital motion of the outer planet could be detected and measured during the lensing event, these discoveries marked the emergence of the technique as a powerful and independent exoplanet probe over an important region of planetary mass and orbital radius.

Introduction

Gravitational lensing In general relativity, the presence of matter (energy density) distorts spacetime, and the path of electromagnetic radiation is deflected as a result. Under certain conditions, light rays from a distant background object (the source) are bent by the gravitational potential of a foreground object (the lens) to create images of the source which are distorted (and possibly multiple), and which may be highly focused and hence significantly amplified. Its manifestation depends upon the fortuitous alignment of the background source, the intervening lens, and the observer.

Different regimes are generally recognised for gravitational lensing, depending on whether effects are discernible at an individual object level (strong lensing), or only in a statistical sense (weak lensing).

Type
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Information
The Exoplanet Handbook , pp. 83 - 102
Publisher: Cambridge University Press
Print publication year: 2011

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  • Microlensing
  • Michael Perryman, Max-Planck-Institut für Astronomie, Heidelberg
  • Book: The Exoplanet Handbook
  • Online publication: 01 June 2011
  • Chapter DOI: https://doi.org/10.1017/CBO9780511994852.006
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  • Microlensing
  • Michael Perryman, Max-Planck-Institut für Astronomie, Heidelberg
  • Book: The Exoplanet Handbook
  • Online publication: 01 June 2011
  • Chapter DOI: https://doi.org/10.1017/CBO9780511994852.006
Available formats
×

Send book to Google Drive

To send content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about sending content to Google Drive.

  • Microlensing
  • Michael Perryman, Max-Planck-Institut für Astronomie, Heidelberg
  • Book: The Exoplanet Handbook
  • Online publication: 01 June 2011
  • Chapter DOI: https://doi.org/10.1017/CBO9780511994852.006
Available formats
×