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Potential of long-baseline infrared interferometry for narrow-angle astrometryNarrow-angle astrometry has many astrophysical applications, from the measurement of parallaxes to the search for planets around nearby stars. Ground-based long-focus telescopes with photoelectric detectors have achieved accuracies of about 2-3 milliarcsec in 1 h. This accuracy is limited primarily by the atmosphere, and is consistent with models of atmospheric turbulence. However, applying these turbulence models to observations with long-baseline interferometers yields astrometric errors that are far smaller than can be achieved with long-focus telescopes. The predictions for the ultimate accuracy of ground-based narrow-angle astrometry using long-baseline IR (2.2 micron) stellar interferometers are very promising. With the excellent seeing at a high altitude site like Mauna Kea, the atmospheric limit for a 1 h astrometric measurement is expected to be of the order of 10 microarcsec for 1 h of integration. This two-order-of-magnitude improvement over conventional measurements is due to two effects. One is that a long-baseline IR interferometer can find useful reference stars very near an arbitrary target star, so that the atmospherically-induced motions of both stars are highly correlated. The second is that the baseline length can be much larger than the separation of the stellar beams in the turbulent atmosphere, resulting in a reduction in astrometric error with increasing baseline length.
Document ID
19930060062
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Shao, M.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Colavita, M. M.
(JPL Pasadena, CA, United States)
Date Acquired
August 16, 2013
Publication Date
August 1, 1992
Publication Information
Publication: Astronomy and Astrophysics
Volume: 262
Issue: 1
ISSN: 0004-6361
Subject Category
Astronomy
Accession Number
93A44059
Distribution Limits
Public
Copyright
Other

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