J/MNRAS/442/3604 Variability of the PGa star HD 19400 (Hubrig+, 2014)
Abundance analysis, spectral variability, and search for the presence of a
magnetic field in the typical PGa star HD 19400.
Hubrig S., Castelli F., Gonzalez J.F., Carroll T.A., Ilyin I., Schoeller M.,
Drake N.A., Korhonen H., Briquet M.
<Mon. Not. R. Astron. Soc. 442, 3604 (2014)>
=2014MNRAS.442.3604H 2014MNRAS.442.3604H
ADC_Keywords: Stars, peculiar ; Stars, variable ; Abundances ; Magnetic fields
Keywords: stars: abundances - stars: atmospheres - stars: chemically peculiar -
stars: individual: HD 19400 - stars: magnetic field -
stars: variables: general
Abstract:
The aim of this study is to carry out an abundance determination, to
search for spectral variability and for the presence of a weak
magnetic field in the typical PGa star HD19400. High-resolution, high
signal-to-noise HARPS spectropolarimetric observations of HD19400
were obtained at three different epochs in 2011 and 2013. For the
first time, we present abundances of various elements determined using
an ATLAS12 model, including the abundances of a number of elements not
analysed by previous studies, such as NeI, GaII, and XeII. Several
lines of As II are also present in the spectra of HD19400. To study
the variability, we compared the behaviour of the line profiles of
various elements. We report on the first detection of anomalous shapes
of line profiles belonging to Mn, and Hg, and the variability of the
line profiles belonging to the elements Hg, P, Mn, Fe, and Ga. We
suggest that the variability of the line profiles of these elements is
caused by their non-uniform surface distribution, similar to the
presence of chemical spots detected in HgMn stars. The search for the
presence of a magnetic field was carried out using the moment
technique and the SVD method. Our measurements of the magnetic field
with the moment technique using 22 MnII lines indicate the potential
existence of a weak variable longitudinal magnetic field on the first
epoch. The SVD method applied to the MnII lines indicates
Bz=-76±25G on the first epoch, and at the same epoch the SVD
analysis of the observations using the Fe II lines shows
Bz=-91±35G. The calculated false alarm probability values, 0.008
and 0.003, respectively, are above the value 10-3, indicating no
detection.
Description:
Table 3 contains line by line abundances of HD19400 from the ATLAS12
model with parameters Teff=13500K and logg=3.9.
The spectropolarimetric observations of HD 19400 have been obtained
with the HARPS instrument attached to ESO's 3.6m telescope at La Silla
during 3 nights: 2011-12-15, 2011-12-16, and 2013-07-19.
Objects:
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RA (2000) DE Designation(s)
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03 02 15.45 -71 54 08.8 HD 19400 = HR 939
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 103 197 Line by line abundances of HD19400 from the ATLAS12
model with parameters Teff=13500K, logg=3.9
refs.dat 139 16 log(gf) references
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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2- 10 F9.4 0.1nm lambda [3856/6718] Wavelength of line λ
12- 17 A6 --- Ion Element name and ionization stage
19- 24 F6.3 [-] log(gf) Oscillator strength
26- 31 A6 --- r_log(gf) Reference for oscillator strength,
in refs.dat file
33- 42 F10.3 cm-1 Xlow Lower state excitation potential
44- 48 F5.1 0.1pm EW ? Equivalent width of line (mÅ)
50 A1 --- n_log(N/Nt) [pn] "p" when the abundance is derived from
the profile, "n" for non-observed line
52- 53 A2 --- l_log(N/Nt) [≤ ] Limit flag on log(N/Nt)
(the line was not observed)
54- 59 F6.3 [-] log(N/Nt) Derived abundance (log(N(Ion)/Ntot))
60- 61 A2 --- u_log(N/Nt) [: ] Uncertainty flag on log(N/Nt)
63-103 A41 --- Remarks Notes on the fitting
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Ref Reference code for log(gf)
8- 26 A19 --- BibCode BibCode
28- 55 A28 --- Aut Author's name
57-139 A83 --- Com Comments
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Acknowledgements:
Swetlana Hubrig, shubrig(at)aip.de
(End) Patricia Vannier [CDS] 28-Jul-2014