We present the results of a deep CCD-based IZ photometric survey of a ~ 1 deg(2) area in the central region of the Pleiades Galactic open cluster. The magnitude coverage of our survey (from I ~ 17.5 down to 22) allows us to detect substellar candidates with masses between 0.075 and 0.03 Msun. Details of the photometric reduction and selection

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We investigate the cosmology of x-matter with pressure, px, and density, ρx, related by px=w0ργx(w0 0). For γ >1, this x-matter behaves like a cosmological constant when a

Ursa Minor (UMi) is one of the closest satellites of the Milky Way (d=69 kpc). It is possibly a disrupted dSph interacting with the external Galactic halo. This makes its study quite necessary in the forementioned context. In this paper we present preliminary results of a wide field photometry survey of UMi and discuss the presence of an

IAUC 7086 available at Central Bureau for Astronomical Telegrams.

Very high-resolution (R ~ 110 000) spectroscopic observations of the very low-mass star VB 8, obtained with the Utrecht Echelle spectrograph (UES), are presented. A flare occurred during the third of a series of four consecutive spectra. This event produced significant enhancement in the strength of the emission lines of He i D3 and Hα in VB 8, as