naa a22 4500 510790437 CHVBK 20180411083317.0 cr unu---uuuuu 180411e20130501xx s 000 0 eng 10.1134/S1063773713050058 doi (NATIONALLICENCE)springer-10.1134/S1063773713050058 Chemical composition and evolutionary status of the Ap star HD 138633 [Elektronische Daten] [A. Titarenko, T. Ryabchikova, O. Kochukhov, V. Tsymbal] We present the results of our study of the atmospheric chemical composition and evolutionary status for the chemically peculiar Ap star HD 138633. In contrast to ordinary Ap stars that exhibit strong lines of rare-earth elements in their spectra, these elements are represented very poorly in the spectrum of HD 138633. The magnetic field is estimated to be less than 700 G, which is also atypical of peculiar Ap stars. We have detected a stratification of such elements as Fe, Si, Ca, and Y in the atmosphere of HD 138633 whose pattern agrees qualitatively with the predictions of the theory of diffusive separation of elements under the joint action of gravity and radiation pressure forces. The nonuniform distribution obtained by assuming a stepwise distribution of elements in depth agrees qualitatively with the stratification distribution for β CrB. The search for pulsations points to the possible existence of lowamplitude pulsations with a period of about 17 min. Pleiades Publishing, Ltd., 2013 stars-chemically peculiar stars nationallicence chemical composition nationallicence atmospheric pulsations nationallicence magnetic field nationallicence Titarenko A. Department of Astronomy, Faculty of Physics, Moscow State University, 119991, Moscow, Russia aut Ryabchikova T. Institute of Astronomy, Russian Academy of Sciences, ul. Pyatnitskaya 48, 119017, Moscow, Russia aut Kochukhov O. Department of Astronomy and Space Physics, Uppsala University, Box 515, 751-20, Uppsala, Sweden aut Tsymbal V. Faculty of Physics, Taurida National University, pr. Vernadskogo 4, 95007, Simferopol, Ukraine aut Astronomy Letters SP MAIK Nauka/Interperiodica 39/5(2013-05-01), 347-356 1063-7737 39:5<347 2013 39 11443 https://doi.org/10.1134/S1063773713050058 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1134/S1063773713050058 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Titarenko A. Department of Astronomy, Faculty of Physics, Moscow State University, 119991, Moscow, Russia aut NATIONALLICENCE 700 1- Ryabchikova T. Institute of Astronomy, Russian Academy of Sciences, ul. Pyatnitskaya 48, 119017, Moscow, Russia aut NATIONALLICENCE 700 1- Kochukhov O. Department of Astronomy and Space Physics, Uppsala University, Box 515, 751-20, Uppsala, Sweden aut NATIONALLICENCE 700 1- Tsymbal V. Faculty of Physics, Taurida National University, pr. Vernadskogo 4, 95007, Simferopol, Ukraine aut NATIONALLICENCE 773 0- Astronomy Letters SP MAIK Nauka/Interperiodica 39/5(2013-05-01), 347-356 1063-7737 39:5<347 2013 39 11443 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer