HDE 269896: UNA SUPERGIGANTE ESPECIAL DE LA NUBE MAYOR DE MAGALLANES

CORTI, M. A.; WALBORN, N. R.

Boletin de la Asociacion Argentina de Astronomia

Dubner Gloria, Garcia Lambas Diego, Piatti Andres & Vareilles Federico

Año: 2008 vol. 51 p. 85 - 88

The star HDE~269896, a hypergiant in the Large Magellanic Cloud, withspectral type ON9.7~Ia$^+$, is a special case within the known OB Zoo. We havediscovered strong emission from the N~II 5000~\AA\ complex in its spectrum,and the previously known He~II $\lambda$4686 emission, with an anomalousstrength for the spectral type, has also been observed. Comparing HDE~269896 with other objects that show N~II emission lines, such as WN10 and WN11 types, we find that this star is highly evolved, albeit less so than the latter stars. Thus, it is reasonable to propose that HDE~269896 should be in an immediate pre-WNVL (Very Late WN) state. Another characteristic of this star is the unusually wide range of ionization present in its extended atmosphere. Subsequent analysis of its spectrum will permit a better understanding of both the relevant atomic physics and the structure of this unusual atmosphere.