The chemical composition of MCP star

HD 25354

YUSHCHENKO VOLODYMYR Odessa National University, Ukraine

The collaborators:

Vera Gopka - Odessa National University, Ukraine Angelina Shavrina – Kiev, Main National Observatory,

Ukraine Alexander Yushchenko - Sejong University, KoreaFaig 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

Decay times of the most stable isotopes 43 Tc43 Tc 98 98 4.24.2∙10∙106 6

yy91 Pa91 Pa 231 231

32760 32760 yy

6161 PmPm 145 17.7 145 17.7 yy

9292 UU 238 238 4.47∙104.47∙1099 y y

8484 PoPo 209209 102 102 yy 9393 NpNp 237 237 2.14∙ 2.14∙ 101066 y y

8585 AtAt 210 210 8.1 8.1 hh

9494 PuPu 244 244 8.08∙108.08∙1077 y y

8686 RnRn 222222 3.823 3.823 dd

9595 AmAm 243 243 7370 7370 yy

8787 FrFr 223223 21.8 21.8 mm

9696 CmCm 247247 1.56∙101.56∙1077 yy

8888 RaRa 226226 1600 1600 yy

9797 BkBk 247247 1380 1380 yy

8989 AcAc 227 227 21.77 21.77 yy

9898 CfCf 251251 898 898 yy

9090 ThTh 232232 1.4∙101.4∙101010 yy

9999 EsEs 252 252 471.7 d471.7 d

HD25354 in SIMBAD:

1972

Identification of Am II (Jaschek & Brandi, 1972)

(Z=95, A=(Z=95, A=243243, decay time =, decay time = 7370 7370 yy ) )

The list of Cm I lines (Jaschek & Brandi, 1972)

(Z=96, A=247247, decay time= , decay time= 1.56∙101.56∙1077 y)y)

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

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

Babcock found the magnetic field of HD 25354: 120 Gauss

Babcock, H.W.Magnetic Fields of the A-Type Stars Astrophysical Journal, 1958, Vol. 128, P. 228.

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 Fields

and Rotation of Stars with Strong and Weak Anomaliesin the Continuum Energy Distribution1

I. 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

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.

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

Floquet (1982): variation of equivalent widths with phase

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

Variations of lines change the picture:

Comparison of two observed spectra of HR 465 (filled and open squares),

obtained at different time and the synthetic spectrum (line)

It is necessary to investigate HD 25354

at different phases

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

The model of HD25354

• Теff = 12750 K

• lоg g= 4.15• vmicro= 0.2 km/sec

• It was found from the analysis of iron lines (Fe II, Fe III & Fe I)

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

The typical spectrum of HD25354:

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

• 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.

• 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, and tungsten (Th, U, W)

were not rejected.

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= 9050 K, lgg=3.5, R=3.7± 1.5R. • The effective temperature of HD25354 found

using the СаII calibrations is 9050 K

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.

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 example Dy 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

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

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

Chemical composition of HD25354

No lines of Am and Cm were found

• 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.

HD 25354

HD 25354

HD 25354

HD 25354

HD 25354 Dy lines near the strongest line of Hg

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.

Przybylsky’s star (HD101065)

Thanks for your attention