Detection and spectroscopy of exo-planets like Earth

J. R. Angel, James H. Burge, Neville J. Woolf

Research output: Chapter in Book/Report/Conference proceedingConference contribution

19 Scopus citations


Planets with mass similar to Jupiter's are now known to orbit nearby stars. Are there also planets like Earth? If so, their thermal emission should be directly detectable, and thermal spectra could identify the strong features of carbon dioxide, water and ozone at the levels seen in Earth. But the very close angular separation (approximately 0.1 arcsec) and huge brightness difference (approximately 107) between a star and such a planet present a technical challenge. Space interferometry could in principle solve both problems, by using destructive interference to cancel out the stellar emission, and aperture synthesis to recover high angular resolution images. We show how these two functions conflict, and point to a new interferometer design which allows them to be reconciled. One key technical challenge is to combine beams with strictly controlled amplitude and achromatic phase inversions, so as to cancel the stellar disc flux by a factor of a million. We show how refractive elements analogous to an achromatic lens can be used for this purpose.

Original languageEnglish (US)
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
PublisherSociety of Photo-Optical Instrumentation Engineers
Number of pages4
ISBN (Print)0819422681
StatePublished - 1997
EventOptical Telescopes of Today and Tomorrow - Landskrona/Hven, Swed
Duration: May 29 1996May 29 1996

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


OtherOptical Telescopes of Today and Tomorrow
CityLandskrona/Hven, Swed

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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