SPECTROSCOPICAL STUDY OF FAINT SOUTHERN CEPHEIDS WITH SOUTHERN AFRICAN LARGE TELESCOPE (SALT). FIRST RESULTS.

Автор(и)

  • I. A. Usenko Astronomical Observatory, Odessa National University, Mykolaiv Astronomical Observatory, Ukraine
  • A. Yu. Kniazev South African Astronomical Observatory Southern African Large Telescope Foundation, South Africa
  • V. V. Kovtyukh Astronomical Observatory, Odessa National University, Ukraine
  • S. I. Belik Astronomical Observatory, Odessa National University, Ukraine
  • L. N. Berdnikov Sternberg Astronomical Institute, Russian Federation

DOI:

https://doi.org/10.18524/1810-4215.2017.30.117156

Ключові слова:

Stars, Cepheids, atmosphere parameters, chemical composition

Анотація

First Cepheids observations using echelle-spectrograph HRS fed by Southern African Large Telescope (SALT) were realized during 2016. All spectra have been obtained in the medium resoltion mode (R≈31000–41000) wth high S/N ratio near 50–220. All data were processed using package developed by authors based on the standard system of astronomical data reduction MIDAS. Using new echelle data we found the atmosphere parameters and chemical composition for 30 faint Cepheids of southern hemisphere, where for the most of theses stars these results we obtained for the first time. 28 stars are Cepheids after the first-dredge up stage, while ASAS 075842-25336.1 and ASAS 1131714-6605.0 having remarkable Li I 6707.8 Å absorption line and anomalous CNO and Na content could be consider as first crossing of the Cepheids instability strip.

Посилання

Castelli F., Kurucz R.L.: 2004, arXiv: astro-ph/0405087.

Galazutdinov G.A.: 2007, http://gazinur.com/DECH-software.html.

Kovtuykh V.V.: 2007, MNRAS 378, 617.

Kupka F., Piskunov N.E., Ryabchikova T.A., Stempels H.S., Weiss W.W.: 1999 A&A, 138, 119.

Luck R.E.: 2014, AJ, 147, 137.

Luck R.E., Lambert D.L.: 2011, A, 142, 136.

Mel’nik A.M., Rautiainen P., Berdnikov L.N., Dambis A.K., Rastorguev A.S.: 2015, AN, 336, 70.

##submission.downloads##

Опубліковано

2017-12-01

Номер

Розділ

Астрофізика (зоряні атмосфери, взаємодіючі подвійні системи, змінні зорі)