J/AZh/84/714 Optical spectral variability of BD+48 1220 (Klochkova+, 2007)
Evolutionary stage of the spectral variable BD+48 1220=IRAS 05040+4820.
Klochkova V.G., Chentsov E.L., Tavolzhanskaya M.S., Panchuk V.E.
<Astron. Zh. 84, 714 (2007)>
=2007AZh....84..714K 2007AZh....84..714K
=2007ARep...51..642K 2007ARep...51..642K
ADC_Keywords: Stars, variable; Spectroscopy
Abstract:
Based on high-resolution observations (R=60000 and 75000), we have
studied the optical spectral variability of the star BD+48 1220,
identified with the IR-source IRAS 05040+4820. We have measured the
equivalent widths of numerous absorption lines of neutral atoms and
ions at wavelengths from 4500 to 6760Å, as well as the
corresponding radial velocities. We use model atmospheres to determine
the effective temperature Teff=7900K, surface gravity log g=0.0,
microturbulence velocity xit=6.0, and the abundances for 16 elements.
The star's metallicity differs little from the solar value:
[Fe/H]=-0.10dex. The main peculiarity of the chemical composition of
the star is a large He-excess, derived from the HeI 5876Å
absorption, [He/H]=+1.04, and the equally large O-excess,
[O/Fe]=+0.72dex. The C-excess is small, [C/Fe]=+0.09dex, and the ratio
[C/O]≤1. We obtained a revised relation for the light-metal
abundances: [Na/Fe]=+0.87 with [Mg/Fe]=-0.31. The barium abundance is
low, [Ba/Fe]=-0.84. The radial velocity of the star measured from
photospheric absorption lines over three years of observations varies
in the interval V☉=-(7-15)km/s. Time variable differential line
shifts have been revealed. The entire set of available data (the
luminosity Mv~-5mag, velocity Vlsr~-20km/s, metallicity
[Fe/H]=-0.10, and peculiarities of the optical spectrum and chemical
composition) confirms the status of BD+48 1220 as a post-AGB star with
He- and O-excesses belonging to the Galactic disk.
Objects:
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RA (2000) DE Designation(s)
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05 07 50.296 +48 24 09.42 BD+48 1220 = IRAS 05040+4820
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 38 22 Elemental abundances in the atmosphere of
BD+48 1220 (Teff=7900K, logg=0.0, xit6.0)
tablea1.dat 77 550 Residual line intensities in fractions of
continuum and HRV in spectra of BD+48 1220
obtained on various dates
tablea2.dat 46 199 Atomic parameters of lines in spectrum of
BD+48 1220 obtained on 2004-04-10, and
corresponding atmospheric elemental abundances
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Table1: Observations of BD+48 1220 with the 6-m telescope.
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Date Integration Delta lambda R S/N
s Å
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02.12.2002 2x3600 4520-6000 60000 75
09.09.2003 2x3600 4520-6000 60000 100
10.01.2004 2x3600 5280-6760 75000 85
08.03.2004 2x3600 5280-6760 75000 115
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Table 3: Average heliocentric radial velocities for line groups and
some individual lines, from spectra of BD+48 1220 obtained
on different dates.
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Spectral details HRV (km/s)
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2002-12-02 2003-09-09 2004-01-10 2004-03-08
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Absorption cores:
FeII, CrII, etc. (r->1)
-14.8 -6.8 -15.3 -8.2
Halpha -27. -28.
Hbeta -14.8 -10.6
Absorption line wings at r=0.90-0.95:
- -14. -9.5 -15.5 -13.0
Maximum extension of short-wavelength wings:
FeII(42) -70. -61. -65. : -70.
Halpha -65. : -57. :
Emission features:
FeII(40, 46) -18.
Halpha -15. -13. :
Interstellar lines and bands:
NaI -25,-3 -26,-2 -27,-2.5 -28,-2
DIBs -3. : -2.5:
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 2 A2 --- E Element
4- 8 F5.2 [-] logeps(E) Solar abundance for E element (1)
10- 13 A4 --- Ion Ion identification
17- 21 F5.2 [-] logeps(X) Star abundance for X element (1)
24- 27 F4.2 [-] e_logeps(X) ? rms uncertainty on logeps(X)
30- 31 I2 --- o_logeps(X) Number of lines used
34- 38 F5.2 [Sun] [X/Fe] Solar [X/Fe] abundance value (2)
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Note (1): For logeps(H)=12.0
Note (2): Solar abundances are taken from Lodder, 2003ApJ...591.1220
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- El Element with multiplet number (1)
12- 18 F7.2 0.1nm Lambda ? Wavelength expressed in Angstroem
19 A1 --- u_Lambda [:] Uncertainty flag on Lambda
22- 25 F4.2 --- Res1 ? Residual line intensity for observation
on 2002-12-02
26 A1 --- u_Res1 [:] Uncertainty flag on Res1
28- 32 F5.1 km/s HRV1 ? Heliocentric radial velocity for observation
on 2002-12-02
33 A1 --- u_HRV1 [:] Uncertainty flag on HRV1
36- 39 F4.2 --- Res2 ? Residual line intensity for observation
on 2003-09-09
40 A1 --- u_Res2 [:] Uncertainty flag on Res2
42- 46 F5.1 km/s HRV2 ? Heliocentric radial velocity for observation
on 2003-09-09
47 A1 --- u_HRV2 [:] Uncertainty flag on HRV2
50- 53 F4.2 --- Res3 ? Residual line intensity for observation
on 2004-01-10
54 A1 --- u_Res3 [:] Uncertainty flag on Res3
56- 60 F5.1 km/s HRV3 ? Heliocentric radial velocity for observation
on 2004-01-10
61 A1 --- u_HRV3 [:] Uncertainty flag on HRV3
64- 67 F4.2 --- Res4 ? Residual line intensity for observation
on 2004-03-08
68 A1 --- u_Res4 [:] Uncertainty flag on Res4
70- 74 F5.1 km/s HRV4 ? Heliocentric radial velocity for observation
on 2004-03-08
75 A1 --- u_HRV4 [:] Uncertainty flag on HRV4
76- 77 A2 --- n_HRV4 [em] emission
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Note (1): DIB = diffuse interstellar band
Table 2: Diffuse bands in the spectrum of BD+48 1220
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lambda Wlambda
Å mÅ
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5747 42
5780 227
5797 80
6195 25
6203 64
6270 64
6379 54
6425 13
6613 104
6699 17
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Byte-by-byte Description of file: tablea2.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- Ion Element
8- 15 F8.3 0.1nm Lambda Wavelength expressed in Angstroem
18- 24 F7.4 eV EP Excitation potentials of the lower level
28- 33 F6.3 [-] loggf Oscillator strength (log gf)
36- 38 I3 0.1nm EW Equivalent width
41- 46 F6.2 [-] log(eps) Abundance of the element (1)
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Note (1): For log(eps(H)=12 in atmosphere of BD+48 1220 obtained with
parameters Teff=7900K,logg=0.5, ξt=6.0. --------------------------------------------------------------------------------
(End) Veta Avedisova [INASAN] 08-Mar-2008