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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
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
Comparison of two observed spectra of HR 465 (filled and open squares),
obtained at different time and the synthetic spectrum (line)
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)
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
• 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:
The value of effective temperature is found to be equal 12750 K. earlier values are in the range from 9000 K to 10000 K.