ISSN:
1572-946X
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract The hyperfine structures of HCNJ=1−0 are observed toward S140 with a high-resolution spectroscope. The measured ratiosR 02=T a * (F=0−1)/T a * (F=2−1) andR 12=T a * (F=1−1)/T a * (F=2−1) are 0.29±0.03 and 0.43±0.03 separately. A large velocity gradient model, the escape probability method and spherical approximation are adopted to calculate the radiative transfer. The correlations between the ratios of the hyperfine satellites and density (or optical depth) have been studied. To fit the measured ratios, a density of (0.9±0.1)×106 cm−4 is obtained toward S140 center. According to the differences between the calculated excitation temperatures of the hyperfine satellites, one finds that the so-called hyperfine anomalies is caused by the unrealistic LTE assumption.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00644236
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