The Postmaximum Spectrum of χ Cygni.

Abstract

view Abstract Citations (36) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Postmaximum Spectrum of χ Cygni. Merrill, Paul W. Abstract The spectrum of the long-period variable x Cygni combines characteristics of classes M and Numerous bright lines are unusually intense. Spectrograms extending from the blue into the ultraviol dispersion 10 A/mm, were obtained over the interval from 41 to 162 days after maximum; the coi sponcling range of magnitude was from 6.3 to 11.4. Dark lines-The atomic-line spectrum resembles that of R Andromedae, class Se, but the TiO bai are as strong as in class M6. The velocities exhibit a very slight increase (algebraic) with advancing ph2 Differences between various cycles are small. Residuals of individual lines behave as in other red v~ ables. Bright lines.-After maximum, bright lines of Fei increased in number from 30 to almost 100. M of them grew stronger throughout the period of observation, but a few high-excitation multiplets I their maximum intensities about 114 days after maximum. The behavior of multiplet (2) illustrates tendency of bright lines to escape from the effects of the reversing layer as the phase advances. A culiarity of physical interest is the inordinately high intensity of bright lines from upper levels z and z5G2. A third level possibly emphasized is w5D4, and others not so outstanding are y5Fi and y5F2. Zr i level x'G4 is the only one that gives use to bright lines. In several other elements possible exami of excitation by line coincidence are noted. Numerous bright lines of COI and Ni i have been identified. Multiplets having certain lower levels emphasized. This fact probably finds its explanation in the different relative intensities of absorpt and emission lines at various excitation potentials. Numerous bright lines of Fe ii became outstanding with advancing phase; forbidden lines appea about 100 days after maximum and strengthened rapidly during the next two months. Other bright II discussed are those of H, Mg i, Sii, Mn i, In i, and the curious displaced components of Al I, C~ and other elements. Velocities from lines of H, Feu, and Tin agree with one another aiid vary little with phase; velocil from Fe i lines increase slightly with excitation potential and with phase. Observations of R Androme~ and x Cygni suggest that Se variables have smaller periodic variations in the positions of lines 1~ bright and dark than do Me variables. Wave lengths of numerous bright lines measured on Plate Ce 3505, phase +162 days, magniti 11.4, are collected in Table 13. The table indicates how the intensity behaves as the phase advances number of str9ng lines remain unidentified Publication: The Astrophysical Journal Pub Date: September 1947 DOI: 10.1086/144958 Bibcode: 1947ApJ...106..274M full text sources ADS | Related Materials (1) Reprint: 1947CMWCI.735....1M