Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

A laboratory demonstration of the capability to image an Earth-like extrasolar planet

Abstract

The detection and characterization of an Earth-like planet orbiting a nearby star requires a telescope with an extraordinarily large contrast at small angular separations. At visible wavelengths, an Earth-like planet would be 1 × 10-10 times fainter than the star at angular separations of typically 0.1 arcsecond or less1,2. There are several proposed space telescope systems that could, in principle, achieve this3,4,5,6. Here we report a laboratory experiment that reaches these limits. We have suppressed the diffracted and scattered light near a star-like source to a level of 6 × 10-10 times the peak intensity in individual coronagraph images. In a series of such images, together with simple image processing, we have effectively reduced this to a residual noise level of about 0.1 × 10-10. This demonstrates that a coronagraphic telescope in space could detect and spectroscopically characterize nearby exoplanetary systems, with the sensitivity to image an ‘Earth-twin’ orbiting a nearby star.

This is a preview of subscription content

Access options

Buy article

Get time limited or full article access on ReadCube.

$32.00

All prices are NET prices.

Figure 1: Representative coronagraph images and intensity profiles.
Figure 2: Laboratory images demonstrate contrast at levels required to detect an Earth-twin.

References

  1. Des Marais, D. J. et al. Remote sensing of planetary properties and biosignatures on extrasolar terrestrial planets. Astrobiology 2, 153–181 (2002)

    ADS  CAS  Article  Google Scholar 

  2. Brown, R. A. Single-visit photometric and obscurational completeness. Astrophys. J. 624, 1010–1024 (2005)

    ADS  Article  Google Scholar 

  3. Traub, W. A. et al. TPF-C: status and recent progress. Proc. SPIE 6268, OT1–OT14 (2006)

    Google Scholar 

  4. Kaltenegger, L. & Fridlund, M. The Darwin mission: search for extra-solar planets. Adv. Space Res. 36, 1114–1122 (2005)

    ADS  CAS  Article  Google Scholar 

  5. Henry, C. et al. Terrestrial Planet Finder: architecture, mission design, and technology development. Proc. SPIE 5491, 265–274 (2004)

    ADS  Article  Google Scholar 

  6. Cash, W. Detection of Earth-like planets around nearby stars using a petal-shaped occulter. Nature 442, 51–53 (2006)

    ADS  CAS  Article  Google Scholar 

  7. Lyot, B. A study of the solar corona and prominences without eclipses. Mon. Not. R. Astron. Soc. 99, 580–594 (1939)

    ADS  Article  Google Scholar 

  8. Guyon, O., Pluzhnik, E. A., Kuchner, M. J., Collins, B. & Ridgway, S. T. Theoretical limits on extrasolar terrestrial planet detection with coronagraphs. Astrophys. J. Suppl. 167, 81–99 (2006)

    ADS  Article  Google Scholar 

  9. Born, M. & Wolf, E. Principles of Optics (Cambridge Univ. Press, New York, 2002)

    Google Scholar 

  10. Kuchner, M. J. & Traub, W. A. A coronagraph with a band-limited mask for finding terrestrial planets. Astrophys. J. 570, 900–908 (2002)

    ADS  Article  Google Scholar 

  11. Kuchner, M. J., Crepp, J. & Ge, J. Eighth-order image masks for terrestrial planet finding. Astrophys. J. 628, 466–473 (2005)

    ADS  Article  Google Scholar 

  12. Guyon, O. Phase induced amplitude apodization of telescope pupils for extrasolar terrestrial planet imaging. Astron. Astrophys. 404, 379–387 (2003)

    ADS  Article  Google Scholar 

  13. Kasdin, N. J., Vanderbei, R. J., Littman, M. J. & Spergel, D. N. Optimal one-dimensional apodizations and shaped pupils for planet-finding coronography. Appl. Opt. 44, 1117–1128 (2005)

    ADS  Article  Google Scholar 

  14. Vanderbei, R. J., Kasdin, N. J. & Spergel, D. N. Checkerboard-mask coronagraphs for high-contrast imaging. Astrophys. J. 615, 555–561 (2004)

    ADS  Article  Google Scholar 

  15. Soummer, R. Apodized pupil Lyot coronagraphs for arbitrary telescope apertures. Astrophys. J. 618, L161–L164 (2005)

    ADS  Article  Google Scholar 

  16. Riaud, P., Boccaletti, A., Baudrand, J. & Rouan, D. The four quadrant phase mask coronagraph. Publ. Astron. Soc. Pacif. 115, 712–719 (2003)

    ADS  Article  Google Scholar 

  17. Trauger, J. T. et al. Coronagraph contrast demonstrations with the high-contrast imaging testbed. Proc. SPIE 5487, 1330–1336 (2004)

    ADS  Article  Google Scholar 

  18. Trauger, J., Kern, B. & Kuhnert, A. TPF-C Technology Milestone #1 Report (JPL Document D-35484, Jet Propulsion Laboratory, Pasadena, 2006)

    Google Scholar 

  19. Borde, P. J. & Traub, W. A. High-contrast imaging from space: nulling in a low-aberration regime. Astrophys. J. 638, 488–498 (2006)

    ADS  Article  Google Scholar 

  20. Heap, S. R. et al. Space Telescope Imaging Spectrograph coronagraphic observations of β-Pictoris. Astrophys. J. 539, 435–444 (2000)

    ADS  Article  Google Scholar 

  21. Lowrence, P. J. et al. An infrared coronagraphic survey for substellar companions. Astron. J. 130, 1845–1861 (2005)

    ADS  Article  Google Scholar 

  22. Krist, J., Trauger, J. & Moody, D. Studying a simple TPF-C. Proc. SPIE 6265, 3O1–3O11 (2006)

    Google Scholar 

  23. Trauger, J. et al. The Eclipse Mission: a direct imaging survey of nearby planetary systems. Proc. SPIE 4854, 116–128 (2002)

    ADS  Article  Google Scholar 

Download references

Acknowledgements

The speckle nulling algorithm is due to C. Burrows. Development of the HCIT facility is an ongoing activity. Experiments were designed and simulated with the computational models of D. Moody. The HCIT control system was developed by B. Gordon and A. Niessner. Recent speckle nulling runs in white light have been carried out by B. Kern. The optical alignments were carried out by F. Shi and A. Kuhnert. The DM was manufactured by Xinetics Inc. The coronagraph mask was fabricated under the supervision of D. Wilson at JPL’s Micro Devices Laboratory, on glass substrates supplied by Canyon Materials Inc. This work was carried out at JPL with the support of JPL and NASA.

Author Contributions J.T.T. performed HCIT experiments and data analysis at JPL; J.T.T. and W.A.T. co-wrote the paper.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to John T. Trauger.

Ethics declarations

Competing interests

Reprints and permissions information is available at www.nature.com/reprints. The authors declare no competing financial interests.

Supplementary information

Supplementary Information

This file contains Supplementary Discussion, Supplementary Figures 1-2 with Legends, Supplementary Table 1 and additional references. (PDF 2207 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Trauger, J., Traub, W. A laboratory demonstration of the capability to image an Earth-like extrasolar planet. Nature 446, 771–773 (2007). https://doi.org/10.1038/nature05729

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature05729

Further reading

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing