We analyse the frequencies shown by the recently discovered pulsating sdB star PG 1657+416. It has at least four frequencies in the range 6.8--7.8 mHz, which are used to constrain the log g value of the star. Moreover, we derive an estimate of the radial order of the modes on the basis of the observed frequency distribution.

As part of the preparatory work for the upcoming GOYA Survey with GTC/EMIR, the GOYA team obtained deep galaxy number counts in the U, B and K bands, for the Groth strip. We present number count models that simultaneously explain the counts in the three bands. We find that most of the precursors of today's early-type galaxies (ellipticals, S0) must

There is increasing evidence that there is a major bar in the inner Galaxy. The distance to near end of the bar at l = 27° has been directly measured by using red clump giants, and extent of the bar (l=27° to l = -15°, |b| 2°) has also been determined from near and mid IR surveys. The next stage is to use the powerful multi-object capability of

Based on O II recombination lines we present a new calibration (called O II_{RL}) of Pagel's O_{23} indicator to determine the O/H abundance ratio in extragalactic H II regions and emission line galaxies. The O II_{RL} calibration produces O/H abundances about a factor of two higher than those derived from the T(4363) method with t^2 = 0.00. The O

The term overshooting is used to describe two situations: the chemical mixing induced by the convective elements crossing the boundary given by Schwarzschild's criterion (overshooting), or, in addition to that mixing, the change in the temperature gradient in the overshoot region when convection is efficient enough (penetration; Zahn 1991). We show

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