Some Spectroscopic Phenomena of the Eclipse of ε Aurigae

Abstract

view Abstract Citations (5) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Some Spectroscopic Phenomena of the Eclipse of ɛ Aurigae McLaughlin, Dean B. Abstract Radial velocities of Aurigae during eclipse, observed at Ann Arbor, differ sys- tematically from the Yerkes velocities, probably because of the asymmetries of the spec- tral lines. The intrinsic variations of light are synchronous with the velocity variations, with a period of a few months. The relation of light- and velocity-curves is somewhat like that of a Mira starof short period, velocity maximum slightly preceding light maximum. Systematic residuals of several lines are discussed. The largest were those of the hydrogen lines, positive before mid-eclipse and negative afterward, with a range of about 25 km/sec. The Mg u line ~8i shows a residual curve almost the inverse of the velocity-curve. These residuals are readily explained as due to differing amounts of asymmetry of the lines, 4481 showing no asymmetry and the hydrogen lines being most strongly affected. Study of the edges of the hydrogen lines shows that their residuals are due to a flaring-out of the red edge before mid-eclipse and of the violet edge afterward, while the other edge in each case remains near its normal position. All the line residuals and asymmetries can be explained by the shifting of a strong line across a weaker one at mid-edipse. A very similar phenomenon is known to occur in the spectrum of ~3 Lyrae during primary eclipse. It is suggested that these anomalous lines are produced in some way by the absorp- tion of light of the bright star by the atmosphere of the fainter. The lack of similar effects in other eclipsing binaries is attributed to the smaller extent of the atmospheres of most stars as compared with those of supergiants Publication: The Astrophysical Journal Pub Date: March 1934 DOI: 10.1086/143531 Bibcode: 1934ApJ....79..235M full text sources ADS |