Annama: Gram-Scale Survival from a Fast Northern Fireball

This paper computes a complete entry budget for the Annama fall, working only from published values and stated assumptions. The nominal body has a diameter of 0.55 metres at a bulk density of 3.40e+03 kilograms per cubic metre, giving an incoming mass of 0.296 tonnes. At the published entry speed of 24.2 kilometres per second its kinetic energy is 0.0207 kilotonnes of TNT equivalent. At the characteristic altitude of 32 kilometres the exponential atmosphere has a density of 0.0144 kilograms per cubic metre, the ram pressure on the body is 8.42 megapascals, the stagnation heating flux is 1.02e+05 megawatts per square metre, and the aerodynamic deceleration is 689 times terrestrial gravity. The ram pressure first reaches representative material strengths at computed altitudes of 63.9, 47.3 and 35.8 kilometres for the weakest, intermediate and strongest cases examined. The recovered material, the two small recovered stones, amounts to 0.168 kilograms, which is 0.0567 percent of the computed incoming mass. The largest recovered piece, at 0.12 kilograms, has a characteristic diameter of 4.07 centimetres, a terminal velocity of 56.1 metres per second, a fall time of 357 seconds from the end of the luminous path at 20 kilometres, and a wind drift of 3.57e+03 metres under a representative wind. All values are computed by the deposited program from the stated inputs; scenario calculations accompany every headline figure so that the sensitivity of each conclusion to its inputs is visible in the same record.