Spectroscopic abundance determinations for a sample of seven F-G stars have been carried out. The majority of them have large galactic latitudes. One objective in deriving spectroscopic abundances is to differentiate evolved objects seen at high galactic latitudes from the young Population I supergiant stars that happen to have large galactic latitudes but actually belong to the galactic disk. Second, it is important to get good calibrators for photometric metallicity indices. It has been suggested in the past that many high galactic-latitude F-G stars that are classified as supergiants are in reality subgiants or dwarfs. Our spectroscopically derived gravities show that two of the stars studied in this paper, HR 5165 and HD 114520, are not supergiants as classified in the Bright Star Catalogue but are subgiants belonging to the solar neighborhood. In our sample, HR 3229 and HR 8470 display solar abundances and the derived gravities support the bright giant luminosity class ascribed to them. HR 4114, HR 4912, and HR 7671 have abundances significantly different from those of young supergiants of galactic disk. The evolutionary status of these objects is discussed.

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An abundance analysis has been conducted for a sample of nine post‐asymptotic giant branch (AGB) candidate stars; eight of them have not been explored before. We find four very promising objects like HD 105262, HD 53300 and CpD‐62° 5428 among them. We find strong evidence of dust–gas separation through selective depletion of refractive elements in HD 105262. The same effect is also observed in HD 53300, CpD‐62° 5428 and HD 114855 although abundance peculiarities are relatively smaller for the last two stars. We find strong enrichment of nitrogen for HD 725, HD 842, HD 1457, HD 9233 and HD 61227 but no further evidence to support their post‐AGB nature. We have compared the observed [N/C] ratios of these stars with the predictions of evolutionary models which include the rotation‐induced mixing.

distancia. De esta manera hemos obtenido, para la metalicidad, el valor medio [Fe/H] ZW = −1.483 ± 0.006 (estadístico) ±0.090 (sistemático), y para la distancia, 5.000 ± 0.001 kpc (estadístico) ±0.220 (sistemático). La metalicidad y la distancia estimados a partir de dos estrellas RRc son consistentes con los anteriores. Debido a la presencia de enrojecimiento diferencial, derivamos valores individuales de E(B − V ) para las estrellas RR Lyrae analizando sus curvas de color V −I. El valor promedio encontrado es E(B −V ) = 0.23±0.02. Una exploración de las curvas de luz de las estrellas en la región de las blue stragglers condujo al descubrimiento de tres nuevas variables SX Phe. La relación periodo-luminosidad de las estrellas SX Phe se empleó para obtener una determinación independiente de la distancia al cúmulo y de los enrojecimientos individuales. La distancia calculada fue de 5.0 kpc.

We present a CCD VI photometric study of the globular cluster M14. Particular attention is given to the variable stars. This allowed new classifications and cluster membership considerations. New variables are reported; 3 RRc, 18 SR and 1 SX Phe. The Fourier decomposition of RR Lyrae light curves lead to the mean cluster metallicity of [Fe/H]ZW = −1.3 ± 0.2. Several independent methods yield a mean distance of 9.36 ± 0.16 kpc. A Colour-Magnitude diagram outlined by the cluster members enabled a matching with theoretical predictions of isochrones and zero-age horizontal branches, whose fitting to the observations is in good agreement with the above distance and metallicity. The Oosterhoff type of M14 is confirmed as Oo-int, and the pulsating mode distribution of RR Lyrae stars on the HB shows that the bimodal region of the instability strip is shared by RRab and RRc stars. By modelling the mass loss at the RGB after the He flash events, we were able to represent the blue tail of the HB, using a core mass of 0.48 M⊙ and total masses of 0.52-0.55 M⊙. A progenitor star on the MS of 0.84 M⊙ reaches the HB in about 12.5 Gyrs, consonant with previous age determinations of the cluster. Type II Cepheids of M14 may be interpreted as products of post-HB evolution, driven by the complex processes involving the burning of the very thin low mass hydrogen and helium shells of these stars and their minuscule envelopes. No evidences were found in favor of M14 being of extragalactic origin.