Перегляд за Автор "Chini, R."
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Документ MULTIPHASE SPECTROSCOPIC OBSERVATIONS OF THE LONG-PERIOD CEPHEIDS l CARINAE(Astroprint, 2013) Usenko, I. A.; Kravtsov, V. V.; Kovtyukh, Valery V.; Berdnikov, L. N.; Kniazev, A. Yu.; Chini, R.; Fokin, A. B.Thirty three spectra (one spectrum for the each of 33 observational nights) have been performed to cover all pulsational period of the 35.5-days Cepheid l Car. Due to these data we have obtained for the first time the detailed curves of effective temperature, gravity and turbulent velocity. Curves of gravity and turbulent velocity show complicated changes, connceted probably with dynamics of extensive Cepheid’s atmosphere. The mean atmosphere parameters of l Car are: Teff = 4984 15 K; log g = 1.13; Vt = 6.67 km s−1. Having a solar metallicity [Fe/H] = +0.02 dex, this Cepheid demonstrate sudden results for the ”key” elements abundances of yellow supergiants evolution, – all they are close to the solar ones. In this case l Car resembles to SV Vul, – Cepheid with 45-days pulsational period and nearly like spectral type. It is possible that l Car is an object crossing the Cepheids instability strip for the first time. The content of other elements is close to solar one too.Документ SPECTROSCOPIC INVESTIGATIONS OF CEPHEIDS IN CARINA(Astroprint, 2010-07) Usenko, I. A.; Berdnikov, L. N.; Kravtsov, V. V.; Kniazev, A. Yu.; Chini, R.; Hoffmeister, V. H.; Stahl, O.; Drass, H.Spectroscopic investigations of seven southern CepheidsWWCar, SX Car, UZ Car, UY Car, GX Car, HW Car and YZ Car have been performed. It was founded out six objects have metallicities, close to solar one and their CNO-, odd elements and Mg content indicate that these objects are on the stage after the first dredge-up. CepheidWWCar is an unusual objects because it has noticeable overabundance of [C/H] = +0.3 dex, [N/H] = +0.95 dex, whereas sodium in deficient ([Na/H] = -0.46 dex), and magnesium content is the largest ([Mg/H] = -0.12 dex) in comparison with other objects from this list having close pulsation periods.