Spectroscopic Observations of Mira CETI,1934-1952.

Abstract

view Abstract Citations (94) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Spectroscopic Observations of Mira CETI,1934-1952. Joy, Alfred H. Abstract The use of coud spectrograms with dispersions up to 2.3 A/mm permits a more critical study of the spectroscopic behavior of Mira Ceti than was possible with lower dispersions. Eighty-eight spectrograms were measured for velocity. Absorption Iines.-Radial velocities deduced from 70 selected lines, representing 16 cycles of the star's variation, indicate fluctuations from cycle to cycle in amounts comparable with the range within a single cycle. In each cycle, maximum velocity of recession usually occurred shortly after maximum light, but the observations near minimum light are too few to permit conclusions with regard to their application to the pulsation theory. Different elements yield slightly different velocities. The displacements of the Fe lines are correlated with the excitation potential. Emission Iines.-The intensity of the emission varies in different cycles, and the incidence of various lines of different elements and different multiplets is peculiar. In general, the velocities from the bright lines are more regular than those of the absorption lines. The velocities of recession of the metallic lines increase with phase, but the hydrogen velocities show approach until phase +65 days and then join the curve of the metals. With respect to the reversing layer, the velocities are always outward. Bright-line velocities are also correlated with excitation potential. Certain lines are greatiy enhanced by fluorescent effects. The companion.-Variations in the relative intensity of the spectrum of the visual companion indicate that the period of light-fluctuation may be about 12-14 years. The sharp reversal in the bright H and K lines shows a velocity of +52.3 km/sec, which may be the velocity of the star. No other absorption lines occur except the strong P Cygni absorption accompanying the hydrogen lines. Discussion.-Velocity variations within the cycle are confirmed, but the evidence for volume pulsation of the whole star is open to question. Publication: The Astrophysical Journal Supplement Series Pub Date: April 1954 DOI: 10.1086/190002 Bibcode: 1954ApJS....1...39J full text sources ADS | data products SIMBAD (15)