Перегляд за Автор "Carraro, G."

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  • Ескіз
    Документ
    Molybdenum abundance in some open clusters
    (Одеський національний університет імені І. І. Мечникова, 2018) Shereta, E. P.; Carraro, G.; Gorbanova, Tetiana I.; Mishenina, Tamara V.; Шерета, Е. П.; Карраро, Ж.; Горбаньова, Тетяна Іванівна; Мішеніна, Тамара Василівна
    This paper presents the results of determination of the molybdenum abundances in 13 G, K type stars in the open clusters NGC 2477 and NGC 2506. The abundances of molybdenum were determined using stellar atmosphere models by Castelli & Kurucz (2004), as well as a modified STARSP LTE spectral synthesis code (Tsymbal, 1996). For the used Mo I lines 5506 and 5533 Å the oscillator strengths log gf were adopted from the latest version of the VALD database dated 2016 (Kupka et al., 1999). The high resolution spectra were obtained with a VLT telescope at the European Southern observatory (ESO, Chile). We used atmospheric parameters of the investigated stars which we had obtained earlier. We have found out that the molybdenum abundances depend on metallicity [Fe/H] in giants of NGC 2506 and NGC 2477. For the stars in NGC 2506, molybdenum is slightly overabundant as compared to the solar abundance; such an overabundance is slightly higher in the stars of the second investigated cluster NGC 2477. Further investigation of the Mo abundance in larger number of open clusters is required to draw reliable conclusions.
  • Ескіз
    Документ
    On the existence of young embedded clusters at high Galactic latitude
    (2017) Turner, D. G.; Carraro, G.; Panko, Olena O.; Панько, Олена Олексіївна; Панько, Елена Алексеевна
    Careful analyses of photometric and star count data available for the nine putative young clusters identified by Camargo et al. (2015, 2016) at high Galactic latitudes reveal that none of the groups contain early-type stars, and most are not significant density enhancements above field level. 2MASS colours for stars in the groups match those of unreddened late-type dwarfs and giants, as expected for contamination by (mostly) thin disk objects. A simulation of one such field using only typical high latitude foreground stars yields a colour-magnitude diagram that is very similar to those constructed by Camargo et al. (2015, 2016) as evidence for their young groups as well as the means of deriving their reddenings and distances. Although some of the fields are coincident with clusters of galaxies, one must conclude that there is no evidence that the putative clusters are extremely young stellar groups.