Milliarcsecond-resolution observations of IRC+10216

We analyze two lunar occultation lightcurves of the carbon star IRC + 10216 (CW Leo). The two events were recorded in 1989 and 1998, in the near-infrared H and K bands respectively. The results consist of two extended (approximate to2), high-resolution (approximate to0.001), one-dimensional brightness profiles along position angles 164degrees and 304degrees at the two epochs. The profiles show evidence for a bright central spike of emission having a FWHM of 0.035, which is consistent with what is predicted by current models for the photosphere of the central star in IRC + 10216. This feature can be identified with the so-called A component recently revealed by speckle imaging [AA 334 (1998) L5; A&A 357 (2000) 169; A&A 333 (1998) L51], and the so-called core of the southern component observed with the aperture masking technique by Tuthill et al. [ApJ 543 (2000) 284]. The B component, alternatively suggested to mark the actual location of the central star by Osterbart et al. [A&A 357 (2000) 169], also seems to show a FWHM consistent with the above value, but it is well detected only in the 1998 K-band lightcurve, while for the 1989 H-band data the detection is less evident. Our brightness profiles also reveal a wealth of other structures, on several levels of scale, which are consistent with models of episodic dust ejection from the central star [A&A 302 (1995) 483]. (C) 2003 Published by Elsevier B.V.