The continuum energy distributions of the luminous blue variables R127 and R110 in the outburst phase are fitted with a circumstellar envelope model. Both stars show two peaks in their continuum, one near 1250? and t...The continuum energy distributions of the luminous blue variables R127 and R110 in the outburst phase are fitted with a circumstellar envelope model. Both stars show two peaks in their continuum, one near 1250? and the other in the optical band. We suggest that their UV and optical fluxes may have different origins: the UV flux comes from the central star while the optical flux comes from an expanding circumstellar envelope. We construct a model for LBVs consisting of two LTE atmosphere models with different temperatures, and find it to be in agreement with the observed spectral energy distributions of R127 and R110. According to our numerical experiments, R127's continuum is composed of fluxes from a circumstellar envelope of T<SUB>eff</SUB> = 8000 K, R = 485R<SUB>⊙</SUB>, and log g = 1, and from a central star of T<SUB>eff</SUB> = 17?000 K, R = 135R<SUB>⊙</SUB>, and log g = 2.5 with a permeating factor f = 0.5; while R110's continuum can be fitted by a circumstellar envelope of T<SUB>eff</SUB> = 7000 K, R = 350R<SUB>⊙</SUB>, and log g = 0.5, and a central star of T<SUB>eff</SUB> = 25?000 K, R = 27R<SUB>⊙</SUB>, and log g = 3.0 with a permeating factor f = 0.65. Both models show that the non-spherically symmetric, optically thick regions are formed surrounding the central star in the outburst phase. The light of the central star is shielded by the circumstellar envelope so that the visual brightness increases with the decrease/increase of the temperature/radius of the optically thick regions.展开更多
文摘The continuum energy distributions of the luminous blue variables R127 and R110 in the outburst phase are fitted with a circumstellar envelope model. Both stars show two peaks in their continuum, one near 1250? and the other in the optical band. We suggest that their UV and optical fluxes may have different origins: the UV flux comes from the central star while the optical flux comes from an expanding circumstellar envelope. We construct a model for LBVs consisting of two LTE atmosphere models with different temperatures, and find it to be in agreement with the observed spectral energy distributions of R127 and R110. According to our numerical experiments, R127's continuum is composed of fluxes from a circumstellar envelope of T<SUB>eff</SUB> = 8000 K, R = 485R<SUB>⊙</SUB>, and log g = 1, and from a central star of T<SUB>eff</SUB> = 17?000 K, R = 135R<SUB>⊙</SUB>, and log g = 2.5 with a permeating factor f = 0.5; while R110's continuum can be fitted by a circumstellar envelope of T<SUB>eff</SUB> = 7000 K, R = 350R<SUB>⊙</SUB>, and log g = 0.5, and a central star of T<SUB>eff</SUB> = 25?000 K, R = 27R<SUB>⊙</SUB>, and log g = 3.0 with a permeating factor f = 0.65. Both models show that the non-spherically symmetric, optically thick regions are formed surrounding the central star in the outburst phase. The light of the central star is shielded by the circumstellar envelope so that the visual brightness increases with the decrease/increase of the temperature/radius of the optically thick regions.
