view Abstract Citations (4) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Predicted lines of Fe I in the arc and in the sun. Kiess, C. C. ; Moore, Charlotte E. Abstract In their analysis of the arc spectrum of iron, Professor Russell and Miss Moore present a list of 1254 Fe I lines, calculated from term combinations, that are present in the sun's spectrum but have not been reported in laboratory descriptions of the iron spectrum. They state, "It is evident that the spectrum of the iron arc is very far from being fully observed." An opportunity to test this statement was found recently, at the National Bureau of Standards, on some spectrograms on which the iron comparison-spectrum was over-exposed. One set of plates, taken with a Rowland grating, ruled with 20,000 lines per inch, covered the region from 66ooA to 868oA; the other set, taken with a grating ruled by R. W. Wood with 30,000 lines per inch, covered the region 3600A to 4300A. All the faint lines appearing on the plates have been measured and com- pared with the published list of predicted iron lines in the sun's spectrum, with gratifying results. In the regions covered by our observations, there are 231 solar lines in the red, identified by prediction as Fe I, and 268 in the violet a total of 499. Of these predicted lines 28 per cent have now been observed in the arc. The percentages of observed lines, arranged by solar intensity, are distributed as follows: Percentage of Lines Observed Solar Int. Red Violet Total 42 46 0 55 22 34 -I 28 19 22 -2 30 13 23 -3 4 0 4 In addition, there are 18 unclassified iron lines in the red and 131 in the violet list that coincide with solar lines that have heretofore been wholly or partially unidentified. As soon as the laboratory measurements have been confirmed by additional observations with different gratings, doubtless many of these new lines will be classified, and definitively identified in the solar spectrum. National Bureau of Standards, W)ishington, D. C. Publication: The Astronomical Journal Pub Date: October 1950 DOI: 10.1086/106393 Bibcode: 1950AJ.....55..173K full text sources ADS |