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The Physical Theory of Meteors. II. Astroballistic Heat Transfer.

1951; IOP Publishing; Volume: 114; Linguagem: Inglês

10.1086/145485

1538-4357

R. N. Thomas, Fred L. Whipple,

Planetary Science and Exploration

view Abstract Citations (17) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Physical Theory of Meteors. II. Astroballistic Heat Transfer. Thomas, Richard N. ; Whipple, Fred L. Abstract Previous difficulty in formulating a quantitative physical theory of meteors has in large part originated from the wide gap between terrestrial experiments and meteor observations. The physical theory of meteors falls into three aspects: air resistance, heat transfer, and radiation. This paper summarizes an attempt to analyze the heat-transfer aspect from the standpoint of the available meteor data and of some recent laboratory experiments. The section that relates to the laboratory experiments represents the first published attempt to measure heat transfer to bodies in free flight when the velocity is so high that ablation occurs-thus defining the astroballistic region. The free-flight heat transfer in the astroballistic region appears from these experiments to vary with velocity and air density according to the meteor formula rather than according to the conventional aerodynamic formulae established at lower velocities. The heat- transfer efficiency, expressed in terms of that to a Newtonian putty ball, is about 1 per cent in the region near 1-2 km/sec. The meteor results show considerable scatter in values of the heat-transfer efficiency, with no obvious dependence upon velocity or air density and with a favored estimate lying near 5 per cent. A possible interpretation of the scatter of meteor values lies in the fragmenting and flaring of meteors; and the great importance of further study on this point is emphasized. Some considerations on the manmum-sized meteorite capable of surviving intact lead to an independent gross estimate of the heattransfer efficiency. An attempt is made to interpret the deep pitting observed in some meteorites in terms of enhanced ablation on an initially irregular surface, in accordance with some additional free-ffight experiments. Publication: The Astrophysical Journal Pub Date: November 1951 DOI: 10.1086/145485 Bibcode: 1951ApJ...114..448T full text sources ADS | Related Materials (7) Part 1: 1951ApJ...113..475C Part 3: 1952ApJ...116..203T Part 4: 1953ApJ...118..555T Part 5: 1954ApJ...119..438S Part 6: 1954ApJ...120..572C Part 7: 1955ApJ...121..241W Part 8: 1955ApJ...121..521J