Observation of Mass Loss in R CrB during the Visual Light Minimum

Abstract

R CrB at minimum light shows three type of spectra: 1) an absorption line spectrum similar to that observed at maximum light; 2) a sharp emission line spectrum mainly due to singly ionised metals which is displaced to the blue by 3 to 10 kms−1 with reference to the absorption spectrum observed at maximum. This is supposed to be a kind of permanent feature which exists even at the time of light maximum; 3) a broad emission line spectrum consisting of mainly λ3889 of Hel, H and K lines of Call and the D lines of NaI. The widths of the broad emission features indicate expansion velocity of 200 kms−1, much greater than the escape velocity (Gaposchkin 1963, Rao 1975).KeywordsEmission LineOptical DepthBroad EmissionExpansion VelocityPermanent FeatureThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.