Polarization in be‐type stars

Abstract

At I/A = 2.79 pm-1, the comparison of a Be star with a nearby normal R star shows that the interstellar polarization of the Be star is diminished by a factor 0.7.The variable polarization of Be-type stars was detected by SHAKOVSKOJ [IO] and by COYNE and GEHRELS [3].In the emission-lines stars, the observed polarization is of intrinsic as well as of interstellar origin. The intrinsic polarization diminishes in the ultra-violet more rapidly than the interstellar polarizationRecently, COYNE and KRUZEWSKI [4] found that the average polarization for eight Be-type stars is large when the hydrogen absorption is small and vice versa. They observed in seven spectral bands from I/A = 3.03 pm-l to I / A = 1.06 pm-l. ObservationsIn the UBVR system, polarimetric observations of eleven emission-lines stars are presented here at I / A = 2.79, 2.38, 1.87, and 1.61 pm-l. The observation and reduction techniques are described by, except that the analyser of the electro-polarimeter is now a Rochon. ResultsThe results of our observations concerning the Be-type stars (see Tables I and 2 We show results in Table 2 for which the observed polarization diminishes more rapidly in the ultraviolet than the normal interstellar polarization, namely 0.54 < Pulpv < 0.74. We