|Figure 1: H long exposures of P Cyg (top) and the reference star 59 Cyg (bottom) recorded with the CP20 camera at OHP during October 4th 1997 using the AO system BOA from ONERA through a filter ( = 10 nm). The images are smoothed using a moving average window of 44 pixels. Note that the theoretical angular resolution of the 1.52 m telescope at 6563 Å ( arcsec) is closely reached (broken first Airy ring is visible on 59 Cyg) whilst for P Cyg a more complex and resolved structure can be suspected|
suggest an initial mass of 48
and its present mass is estimated to be at the most 40
but lower masses (
are also reported in literature
([Lamers et al. 1983]; [Lamers et al. 1985]; [Turner et al. 1999]). However, the
fine spatial structure of this large amount of excreted matter remains
to be detailed.
P Cyg's relative proximity (
1.8 kpc, [Lamers et al. 1983]) represents an
to observe its radiatively driven mass loss from the starting point out to
interstellar medium. Indeed, at 1.8 kpc, the central star radius
corresponds to a tiny angle of 0.2 milliarcsecond (mas) but the Hemitting
region extends over several tens of arcsecs, and radio emission
attain even larger scales ([Meaburn et al. 1999]).
The optical and radio observations reported to date, depict an essentially clumpy
distribution of matter, both at large ([Taylor et al. 1991]; [Nota et al. 1995]) and
small scales ([Skinner et al. 1998]; [Vakili et al. 1997]),
with temporally variable emission ([Skinner et al. 1997]). These imaging observations
sparse and can loosely constrain the spatial and/or temporal evolution
of the clumps in the nebula.
Moreover, in the optical wavelengths, the star to envelope brightness
remains an obstacle for studying the immediate environment of the central star.
In this paper we report an attempt to observe the H
of P Cyg during an AO run at the OHP observatory on October 1997 using
short exposures collected with a photon-counting camera.
|Figure 2: Synthetic representation of the H region of P Cyg multiplied by the filter transmission used for the adaptive optics imaging of P Cyg. The same filter was used for 59 Cyg. About 45.6% of the transmitted light originates from the line continuum|
The paper is organized as follows. In Sect. 2, we describe the AO+imaging instrumentation used for this study as well as data reduction and calibration procedures. Section 3 describes the image reconstruction in which particular efforts have been made to test the validity of the PSF. The last section makes a critical discussion of our findings, and attention is given on the perspectives opened by the emergencies of new high angular resolution techniques. A need arises for a coordinated campaign for a global approach of P Cyg, and LBVs environment.
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