J/MNRAS/453/3766 Project VeSElkA: HD stars atomic-line analysis (LeBlanc+, 2015)
Project VeSElkA: results of abundance analysis
I - HD 71030, HD 95608, HD 116235 and HD 186568.
LeBlanc F., Khalack V., Yameogo B., Thibeault C., Gallant I.
<Mon. Not. R. Astron. Soc., 453, 3766-3771 (2015)>
=2015MNRAS.453.3766L 2015MNRAS.453.3766L (SIMBAD/NED BibCode)
ADC_Keywords: Stars, peculiar ; Spectroscopy
Keywords: diffusion - stars: abundances - stars: atmospheres -
stars: chemically peculiar
Abstract:
A portion of main-sequence stars, called chemically peculiar (CP) stars,
show important abundance anomalies mainly due to atomic diffusion of
the species within these stars. Certain CP stars have hydrodynamically
stable atmospheres where atomic diffusion may dominate and lead to
vertical abundance stratification there. Recently, Project VeSElkA (a
word meaning rainbow in Ukrainian and standing for "Vertical
Stratification of Element Abundances") was initiated with the goal to
detect vertical stratification of chemical abundances in selected CP stars
using high-resolution spectra with large signal-to-noise ratios. The
first extensive and detailed series of results from atomic-line analysis
is presented here for four stars of Project VeSElkA: HD 71030, HD 95608,
HD 116235 and HD 186568. These stars were recently observed with ESPaDOnS
at Canada-France-Hawaii Telescope. Strong evidence of iron stratification
in the atmospheres of HD 95608 and HD 116235 was found. Chromium also
shows a steep abundance gradient in the upper atmospheres of these two
stars. No evidence of stratification is found for HD 71030 and HD 186568.
Description:
The four stars studied here were observed with ESPaDOnS at CFHT.
High-resolution (R=65000) Stokes IV spectra with large signal-to-noise
ratios were obtained in the spectral range 3700-10500Å and were reduced
with the software package LIBRE-ESPRIT (Donati et al. 1997MNRAS.291..658D 1997MNRAS.291..658D).
Two or more spectra of each star were taken to verify for any spectral
variability. For the four stars studied here, no such variability is
detected. Also, no strong magnetic fields were found. More details about
these observations are given in Khalack & LeBlanc (2015AJ....150....2K 2015AJ....150....2K);
for instance, the exposure times and the signal-to-noise ratios are given
in their table 1 for each star studied here.
Objects:
----------------------------------------------------
RA (ICRS) DE Designation(s)
----------------------------------------------------
08 25 49.88 +17 02 46.6 HD 71030 = * d02 Cnc
11 02 19.78 +20 10 47.4 HD 95608 = * b Leo
13 22 09.69 +05 09 17.2 HD 116235 = * 64 Vir
19 43 51.45 +34 09 45.8 HD 186568 = GC 27310
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4a.dat 54 273 List of selected lines for HD 71030
table4b.dat 54 252 List of selected lines for HD 95608
table4c.dat 54 204 List of selected lines for HD 116235
table4d.dat 54 171 List of selected lines for HD 186568
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See also:
J/PASP/109/9 : Photometry of chemically peculiar stars (Adelman+ 1997)
Byte-by-byte Description of file: table4[abcd].dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- El Element
6- 13 F8.3 0.1nm lambda Wavelength λ (Å)
15- 20 F6.3 [-] loggf Oscillator strength
22- 29 F8.5 [-] logN Log of ratio (Nelem/Ntotal) (1)
31- 37 F7.5 [-] e_logN Uncertainty in logN
39- 44 F6.3 [-] logtau ? Log of optical depth at 5000Å
[log(τ5000)] (2)
46- 54 F9.2 cm-1 Ei Initial energy Ei
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Note (1): The abundance for element relative to the total number of atoms.
Note (2): The lines with no values for the optical depth of line formation
shown were treated within a single profile with a stronger line of
the same species.
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History:
From electronic version of the journal
(End) Tiphaine Pouvreau [CDS] 22-Dec-2017