On the chemical composition and orbit of a diurnal fireball

Abstract

In general, meteor and fireball imaging systems operate during the night, as these mostly employ high-sensitivity recording devices that get fully saturated even under twilight conditions. Lowsensitivity video cameras can be an option to monitor fireball activity in broad daylight [1], although the calibration of the images to get precise astrometries is more complex. But some high-sensitivity CCD cameras with attached autoiris lenses can also operate for some period of time before sunset and after sunrise. These have the advantage that image calibration is straightforward, as these cameras can reach a limiting magnitude of +3/+4 and, so, stars recorded by the same devices during the night can be used as a reference for the astrometric calibration of fireballs recorded during the day. This can be very useful to get precise trajectory, radiant and orbital information of very bright bolides that occur in daylight conditions. Some of the meteor observing stations operated by the SPanish Meteor Network (SPMN) are currently monitoring the night sky with high-sensitivity CCD video cameras configured in such a way that they can also operate during a part of the day. In this context, we present here the preliminary analysis of a threestation sporadic diurnal fireball with an absolute magnitude of about -8±1 imaged at dawn on June 1, 2011.