The ISO-SWS spectrum of P Cygni

Lamers H.J.G.L.M., Najarro F., Kudritzki R.P., Morris P.W., Voors R.H.M., van Gent J.I., Waters L.B.F.M., de Graauw T., Beintema D., Valentijn E.A., Hillier D.J.

Abstract:

The free-free IR excess and the IR emission lines of H and He I of the Luminous Blue Variable P Cygni are observed with the ISO-SWS instrument. The observed profiles and the free-free emission are compared with predictions from a non-LTE model atmosphere with a stellar wind. The observations agree very well with a model that has the following properties: T_eff=18100K, R_*=76R, He/H=0.30 by number, {dot}(M)=3.0x10^-5M/yr and v_{infinity}=185km/s. We observed forbidden emission lines of [Fe II], [Fe III], [Ni II], [Ne II], [Ne III] and [Si II]. From the study of the [Ne II] and [Ne III] lines we find that the Ne abundance is about three times higher than normal. This may be due to clumping in the CS envelope at r=~10³R_*

Keywords:
stars: early-type - stars: mass-loss - stars: atmospheres - stars: supergiants - stars: individual: P Cygni (HD 193237)

Full text