OHANA: Representative science objectives

Olivier Lai, Steve Ridgway, Jean Philippe Berger, Catherine Dougados, Vincent Coudé Du Foresto, Olivier Guyon, Régis Lachaume, Eugene Magnier, Fabien Malbet, François Ménard, Denis Mourard, Guy Perrin, Hélène Sol, Stephen Warren, Julien Woillez

Research output: Contribution to journalConference articlepeer-review

4 Scopus citations


In this poster, we examine the science potential of an 800 meter interferometer such as the OHANA Array. The working assumptions are a K=12 limiting magnitude, a 0.5 milliarcsecond resolution at K band, and a small (diffraction limit of individual telescope) field of view. The science cases described herein are by no means exhaustive and perhaps not even the ones that will eventually be carried out, but serve to illustrate the potential of the array. We expect that operation of the array will be proposal driven, so the actual science will come from the Mauna Kea communities. Our philosophy is that any measurement that can be made at a dedicated interferometer facility should not be a strong driver for OHANA. Therefore the science areas discussed in the poster focus on very high angular resolution measurements of faint sources. In some cases, science which can be addressed with simpler or dedicated facilities at an exploratory level can be carried to a significant new capability with OHANA. A limiting magnitude of 12 was obtained by simple computations, but first tests on the sky with the injection module (See adjacent poster on Phase I) will help narrow down this figure. At such sensitivity, Cepheid pulsations can be studied in considerable detail for a wide range of stellar parameters, leading to enhanced confidence in the accuracy of their use for distance measurement with minimal extrapolation or inferrence. The disk/star interaction zone in young stellar objects can be resolved with unprecedented detail for a range of masses and ages, providing direct information about the jet formation region, accretion rates and disk conditions. The broad line region of active galactic nuclei can be studied in a large number of sources of differing characteristics, testing specific models for AGN nuclear structure. For OHANA Phase III, a dual-star phase tracking capability is planned. With the resulting increased sensitivity, direct brown dwarf diameter measurement will provide a strong check on evolution models. Microlensing events could be resolved and provide unique new information about the lensing and the lensed objects.

Original languageEnglish (US)
Pages (from-to)1410-1423
Number of pages14
JournalProceedings of SPIE - The International Society for Optical Engineering
Issue number2
StatePublished - 2002
EventInterferometry for Optical Astronomy II - Waikoloa, HI, United States
Duration: Aug 22 2002Aug 28 2002


  • Brown dawrfs
  • Cepheids
  • Long baseline optical interferometry
  • Micro-lensing

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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