AG Carinae. II. IUE observations of the ring nebula.
The, P. S.; Viotti, R.; Cassatella, A.; Ponz, D.
Italy, Spain, Germany, Netherlands
Abstract
The authors describe the first ultraviolet observations of the ring nebula surrounding the P Cyg superluminous star AG Car. The spectrum of the nebula resembles that of the central star with strong Fe II and Mg II emission lines. The nebular/stellar continuum ratio is nearly constant from 2000 to 3200 Å. This result and the derived surface brightness distribution suggest that scattering of the starlight by dust particles in the nebula should be the main source of the observed UV radiation. The contribution by the instrumentally scattered light of the star is also analyzed, and found to be small. It is concluded that AG Car has probably evolved recently from a red supergiant phase characterized by a high mass loss rate.