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Observatory, 125, 2324, 2005 NEGATIVE REPORT OF OCCULTATION BY THE D-TYPE ASTEROID
 

Summary: Observatory, 125, 2324, 2005
NEGATIVE REPORT OF OCCULTATION BY THE D-TYPE ASTEROID
(773) IRMINTRAUD
By Apostolos Christou and Mark Bailey
Armagh Observatory
An unusual negative observation is reported of the predicted occultation
of the star HIP 186 by (773) Irmintraud on the morning of 21 July 2004.
Introduction
Stellar occultations by solar system objects (asteroids and satellites) constitute a method
of determining the sizes and shapes of large samples of these bodies using small-aperture in-
struments to a level only otherwise achievable, in some cases, by a few large-aperture ground-
based adaptive optics facilities or the Hubble Space Telescope1. They are also a means of test-
ing the astrometric precision of their ephemerides2 and the physical properties of their extant
atmospheres3. During an occultation, which is a time-critical phenomenon, the asteroid-to-star
geometry projects a narrow, roughly cylindrical shadow track on to the surface of the Earth,
within which the star is briefly occulted.
An observing team of twelve staff and students, including summer students, was divided into
three groups: John McFarland, Bebe Ishak, Anne O'Leary, Mark Purver; Apostolos Christou,
David Asher, Chia-Hsien Lin, Eleanor Nolan; and Mark Bailey, Jonathan McAuliffe, Sharon
McClure, Ciara Quinn. On the evening of 2004 July 20, they travelled approximately 100 miles

  

Source: Armagh Observatory

 

Collections: Physics