title: No evidence of a circumsolar dust ring from infrared observations of the 1991 solar eclipse.
abstract: During the past 25 years there have been many attempts to detect a possible dust ring around the sun, with contradictory results. Before the 1991 eclipse, infrared eclipse experiments used single-element detectors to scan the corona along the ecliptic for excess surface brightness peaks. The availability of relatively large-format infrared array detectors now provides a considerable observational advantage: two-dimensional mapping of the brightness and polarization of the corona with high photometric precision. The 1991 eclipse path included the high-altitude Mauna Kea Observatory, a further advantage to measure the corona out to large angular distances from the sun. Results are reported from an experiment conducted on Mauna Kea with a HgCdTe-array detector sensitive to wavelengths between 1 and 2.5 micrometers, using broad-band J, H, and K filters. Although the sky conditions were not ideal, the H- and K-band surface brightnesses clearly show the inhomogeneous structure in the K-corona and the elliptical flattening of the F-corona, but no evidence of a circumsolar, local dust component out to 15 solar radii.
authors.forename: P
authors.initials: P
authors.lastname: Lamy
authors.forename: J R
authors.initials: JR
authors.lastname: Kuhn
authors.forename: H
authors.initials: H
authors.lastname: Lin
authors.forename: S
authors.initials: S
authors.lastname: Koutchmy
authors.forename: R N
authors.initials: RN
authors.lastname: Smartt