ASSESSMENTS OF PARAMETERS OF A LUMINOUS OBJECT OBSERVED IN THE AREA OF SANTIAGO DE COMPOSTELA ON JANUARY 18, 1994

Abstract

A luminous object observed in Spain in the vicinity of Santiago de Compostela on January 18, 1994 and described by eyewitnesses had characteristic features that are inconsistent with the typical flight of a bolide in the atmosphere. Namely, the object was moving at altitudes from ~ 26 to ~ 3 km at an angle of 18° to the Earth's surface with a low speed of 1–3 km/s, and its glow was bright. This phenomenon has not received a reasonable explanation. In this paper, estimates are made of the possible processes and parameters of the cosmic body whose fall could have caused this event. A scenario is proposed in which a stony asteroid several meters in size enters the atmosphere with the minimum speed of ~ 11.2 km/s. The body decelerates to 3 km/s at an altitude of ~ 26 km due to its disintegration into fragments and a gradual increase in the cross-sectional area of the fragment swarm, as in the well-known pancake models. Then the fragments collimate into one or more chains, due to which they overcome atmospheric resistance on their path of about 75 km and slow down to a speed of ~ 1 km/s only at an altitude of 3 km. The glow is caused by thermal radiation from the surface of numerous fragments heated to a temperature close to the solidus temperature. The mechanism of fragment collimation proposed to explain the event requires further substantiation and study.