Some recent observations of helium lines in the infra-red solar spectrum.

Abstract

view Abstract Citations References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Some recent observations of helium lines in the infra-red solar spectrum. Mohier, Orren C. Abstract Equivalent widths of the three lines: 10123.9A, 10830.4A, and 20583.6A, in the solar spectrum have been measured with the McMath-Hulbert Observatory direct-intensity recording spectrograph, using a Cashman PbS cell. Changes in equivalent width at different points on the disk of the sun have been observed. The observations indicate that 10123.9A and 20583.6A, are indeed solar, but the same observations make the identification 10123.9 Heii and 20583.6 Hei doubtful. The increase in intensity of 10830 (Hei) from center to edge of the disk, in faculous areas, and in dark filaments, is confirmed. It is observed that the intensity of this line at the polar limbs is less than at the equatorial limbs. Changes in 10830 in flares, like the variations of 587G (Hei) discovered by Dodson and van Dijke, are established by the new observations. In the high speed dark flocculi that accompany flares, the line can broaden and deepen until it is one of the most conspicuous features of the solar spectrum McMath-Hulbert Observatory, University of Michigan, Pontiac, Mich. Publication: The Astronomical Journal Pub Date: 1951 DOI: 10.1086/106631 Bibcode: 1951AJ.....56S.135M full text sources ADS |