An Upper Limit on Neutral Calcium in Mer
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A.L. Sprague; R.W.H. Kozlowski; D.M. Hunten; F.A. Grosse
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Article
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1993
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Elsevier Science
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English
โ 224 KB
High-resolution spectroscopic measurements of Mercury were made at \(4227 \AA\) to search for neutral calcium in the atmosphere. An upper limit to the intensity is \(9.0 \mathrm{kR}\); the corresponding \(\mathrm{Ca}\) column abundance is \(<7.4 \times 10^{8}\) atoms \(\mathrm{cm}^{-2}\) with a \(\m