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We present the results of our analysis of spectroscopic observations of α UMi (Polaris) obtained in 1994 (five spectra) and 2001-2004 (30 spectra). The mean atmospheric parameters we derived are as follows:km s −1 in 2001-2004. A comparison of our T eff with those obtained from (B − V ) 0 data during the last 60 yr shows both sporadic and regular changes with a period of 25-30 yr, which is close to the orbital period, 29.9-30.5 yr. We also determined the colour excess E(B − V ) = 0.034 mag, A V = 0.102 mag, and chemical composition for 30 elements to verify the hypothesis that the star crosses the Cepheid instability strip for the first time. With [Fe/H] = +0.07 dex, Polaris shows [C/H] = −0.17 dex, [N/H] = +0.42 dex and [O/H] = −0.00 dex, which corresponds to the third (or fifth) crossing. On the basis of the distance, radius and surface gravity values, Polaris is probably a first-overtone pulsator. Polaris is located near the blue edges of the Cepheid instability strip for the fundamental mode and the first overtone, and an abrupt decrease of the pulsational amplitude and its recent increase could be due to its binarity.

Abstract. We present a study of the high-resolution spectroscopic data for the proto-planetary nebula candidate IRAS 01005+7910. For the first time a careful spectral line identification is carried out, and a significant variability of the optical spectrum is detected. We found absorption lines of C /, N , O , Al , Si , and Mg  (λ4481 Å), as well as emission lines of Si  and [Fe ]. Both absorption and emission components are present in the Balmer lines, Na  resonance D 1,2 lines, He , and Fe  lines. The He  line profiles vary from straight to inverse P Cyg-type on a timescale of days to months. The resonance Na  lines show 5 absorption components at a resolution of R = 60 000. Additionally, the Na  D 2 line exhibits a variable emission component with a width comparable to that of the Balmer line emission components. Using the model atmospheres method within the LTE-approximation, the effective temperature (T eff ∼ 21 500 K), the metallicity [Fe/H] = −0.31, and the ratio C/O > 1 is reported. Finally, we suggest that IRAS 01005+7910 is a carbon-rich post-AGB star with a luminosity log(L/L ) = 3.6 at a distance about 3 kpc.