The chemical composition of MCP star HD 25354

1. The chemical composition of MCP star HD25354 YUSHCHENKO VOLODYMYR Odessa National University, Ukraine

2. The collaborators: • Vera Gopka - Odessa National University, Ukraine • Angelina Shavrina – Kiev, Main National Observatory, Ukraine • Alexander Yushchenko - Sejong University, Korea • Faig Musaev-The International Center for Astronomical, Medical and Ecological Research of RAS and NAS of Ukraine – ICAMER, Ukraine • Maksim Kuznetsov -Kiev, Main National Observatory, Ukraine

5. Decay times of the most stable isotopes

6. HD25354 in SIMBAD:

7. 1972

8. Identification of Am II (Jaschek & Brandi, 1972)(Z=95, A=243, decay time =7370 y )

9. The list of Cm I lines(Jaschek & Brandi, 1972)(Z=96, A=247, decay time= 1.56∙107y)

11. Jaschek & Brandi (1972) used 2 spectrograms:Spectrograms at two different phases:10 Å/mm - December, 10, 195710 Å/mm - November, 10, 1957 wavelength range 3700-4900 ÅÅ

12. Paper and Hartoog used 5 spectra: • August, 1969 and November, 1969 at phases • O.11, 0.13, 0.35, 0.52, 0.87 • 4 Å/mm

13. HD25354 is the source of X-rays: • Fuligni, F., Brini, D.; Dusi, W.; Frontera, F. Flare from the Perseus region in hard X-rays Astrophysical Journal, 1976, Vol. 208, №2, P. L111-L113.

14. Babcock found the magnetic field ofHD 25354: 120 Gauss Babcock, H.W.Magnetic Fields of the A-Type StarsAstrophysical Journal, 1958, Vol. 128, P. 228.

15. MAGNETIC FIELD IS WEAK: 206 G Astrophysical Bulletin, 2009, Vol. 64, No. 3, pp. 239–262. Original Russian Text c I.I. Romanyuk, D.O. Kudryavtsev, E.A. Semenko, 2009, published in Astrofizicheskij Byulleten, 2009, Vol. 64, No. 3, pp. 247–271.Magnetic Fields of Chemically Peculiar Stars. II: Magnetic Fieldsand Rotation of Stars with Strong and Weak Anomaliesin the Continuum Energy Distribution1I. I. Romanyuk*, D.O.Kudryavtsev**, and E. A. Semenko***Special Astrophysical Observatory, Russian Academy of Sciences, Nizhnij Arkhyz, 369167 RussiaReceived February 12, 2009; in final form, March 11, 2009

16. Renson, P.Which is the Star V380 Per? IBVS – 1993 - № 3887. – P. 1. HD25354 is the variable star V380 Per. It was noted that V380 Per is a spectral binary: low amplitude of brightness variations(0.0004-0.0002 mag) period 3.9 days.

17. Floquet M., Astron. & Astrophys., 1982, Vol.112, P. 299-304 • The radial velocities show a variation with period 26 days • The period of spectrum variation is 3.9 days

18. Floquet (1982): variation of equivalent widths with phase

19. Floquet (1982): the map of distribution of elements:

20. Variations of lines change the picture:

21. Comparison of two observed spectra of HR 465 (filled and open squares), obtained at different time and the synthetic spectrum (line)

22. It is necessary to investigate HD 25354 at different phases

23. 2 spectra were obtained at 2-m telescope of peak Terskol observatory • Wavelength interval λλ=3700-9400 Å • Signal to noise S/N>=100 • Spectral resolving power R=40000-60000 • 2006, November, 28-30

24. The model of HD25354 • Теff =12750K • lоg g=4.15 • vmicro=0.2 km/sec • It was found from the analysis of iron lines (Fe II, Fe III & Fe I)

25. Our calculations support Pyper & Hartoog value: Teff=11750 K

26. The typical spectrum of HD25354:

27. HD 25354-the phase of chromium and lanthanide. Strong lines of CrII, FeII, TiII, NdIII, DyIII, ErIII, HoIII…ThIII

28. HD25354- is one of the most intriguing Ар-stars, but all investigations of this object were devoted only to the identification of lines of chemical elements. • No abundances were found earlier.

29. Pyper, D. M.; Hartoog, M. R. Heavy elements in the peculiar A star HD 25354 Astrophys. J. – 1975 - Vol. 198. - P. 555 – 559 analyzed Jaschek & Brandi (1972) paper: • The identification of lines of Am, Cm were not confirmed • The identification of lines of thorium, uranium, andtungsten (Th, U, W) were not rejected.

30. Floquet M. Effective temperature of AP stars Astronomy and Astrophysics. – 1981 - Vol. 101. № 2. - P. 176-183. • The spectral class of the star was found in the range from А1 to А3 by earlier investigators • But the high resolution spectrum of HD25354 can not be fitted by synthetic spectrum calculated with effective temperature 9000-9500 K. • Т= 9050K, lgg=3.5, R=3.7± 1.5R. • The effective temperature of HD25354 found using the СаII calibrations is 9050 K

31. HD 25354 • Kochukhov, O.; Bagnulo, S. Evolutionary state of magnetic chemically peculiar stars Astronomy and Astrophysics – 2006 – Vol. 450. . №2. – P. 763 The effective temperature 9840 K was found using the calibrations of Geneva photometry.

32. HD 25354 • In earlier papers the identification of lines of Dy III, Pr III, Pt II, U II were made. It confirms the high effective temperature. • For exampleDy III lines: Aikman, G. C. L.; Cowley, C. R.; Crosswhite, H. M. Dysprosium III lines in the spectra of peculiar A and B stars Astrophysical Journal, 1979, vol. 232, №1, P. 812

33. Fe II lines in the spectrum of HD 25354Vt = 0.2 km/s

34. Fe II lines in the spectrum of HD 25354Teff= 12750 K

35. Chemical composition of HD25354

36. No lines of Am and Cm were found

37. The lines of Pm II (z=61, lanthanide, without stable elements) show good coincidences with measured line in the spectra of HD25354, but it can be fitted also by other elements.

38. HD 25354

39. HD 25354

40. HD 25354

41. HD 25354

42. HD 25354 Dy lines near the strongest line of Hg

43. HD 25354: The value of effective temperature is found to be equal 12750 K. earlier values are in the range from 9000 K to 10000 K.

44. Przybylsky’s star (HD101065)

45. Thanks for your attention