J/A+A/506/213 B6-B9.5 stars abundance analysis (Niemczura+, 2009)
Abundance analysis of prime B-type targets for asteroseismology.
II. B6-B9.5 stars in the field of view of the CoRoT.
Niemczura E., Morel T., Aerts C.
<Astron. Astrophys. 506, 213 (2009)>
=2009A&A...506..213N 2009A&A...506..213N
ADC_Keywords: Stars, early-type ; Stars, B-type ; Abundances ;
Rotational velocities
Keywords: stars: abundances - stars: atmospheres - stars: chemically peculiar
Abstract:
The CoRoT satellite is collecting precise time-resolved photometry for
tens of asteroseismology targets. To ensure a correct interpretation
of the CoRoT data, the atmospheric parameters, chemical compositions,
and rotational velocities of the stars must be determined.
The main goal of the ground-based seismology support program for the
CoRoT mission was to obtain photometric and spectroscopic data for
stars in the fields monitored by the satellite. These ground-based
observations were collected in the GAUDI archive. High-resolution
spectra of more than 200 B-type stars are available in this database,
and about 45% of them is analysed here.
To derive the effective temperature of the stars, we used photometric
indices. Surface gravities were obtained by comparing observed and
theoretical Balmer line profiles. To determine the chemical abundances
and rotational velocities, we used a spectrum synthesis method, which
consisted of comparing the observed spectrum with theoretical ones
based on the assumption of LTE.
Atmospheric parameters, chemical abundances, and rotational velocities
were determined for 89 late-B stars. The dominant species in their
spectra are iron-peak elements. The average Fe abundance is
7.24±0.45dex. The average rotational velocity is 126km/s, but there
are 13 and 20 stars with low and moderate Vsini values, respectively.
The analysis of this sample of 89 late B-type stars reveals many
chemically peculiar (CP) stars. Some of them were previously known,
but at least 9 new CP candidates, among which at least two HgMn stars,
are identified in our study. These CP stars as a group exhibit Vsini
values lower than the stars with normal surface chemical composition.
Description:
The observational material consists of the high-resolution
(R∼40000-50000) spectroscopic observations of B-type stars obtained
with the ELODIE and FEROS spectrographs. The ELODIE spectrograph was
attached to the 1.93m telescope at the Observatoire de
Haute-Provence, France. The FEROS spectrograph was installed on the
1.52m and 2.2m telescopes at La Silla, Chile. Both instruments are
cross-dispersed, fibre-fed echelle spectrographs. Typical
signal-to-noise ratios of the spectra range from 100 to 150 at 550nm.
The wavelength intervals covered are 390-680nm and 380-910nm for
ELODIE and FEROS, respectively. In our initial sample, we have 160
FEROS spectra and 62 ELODIE spectra of B-type stars. Only the
spectroscopic observations of the B6-B9.5 stars available in the GAUDI
archive are analysed in this paper. We also excluded Be stars,
supergiants and spectroscopic binaries for which the lines of two
stars were visible in the spectra. Basic information about the
analysed stars, including spectral type, name of the spectrograph,
observation date in UT, V magnitude, interstellar reddening,
indications of binarity, and abundance determinations in the
literature are given in Table 1.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 137 93 Description of the analysed stars and their
observations
refs.dat 82 31 References of table1
table2.dat 337 89 Atmospheric parameters, abundances of chemical
elements and rotation velocities of all
analysed stars
table3.dat 33 21 Average abundances for the entire sample and
the non-CP stars
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- HD HD number
8- 15 A8 --- SpType MK spectral type
17- 22 A6 --- Inst Spectrograph
24- 33 A10 "YYYY/DD/MM" Obs.date Observation date
35- 42 A8 "h:m:s" Obs.time Obsertation time of the beginning of
the exposure
44- 47 F4.2 mag Vmag ? V magnitude
49- 52 F4.2 mag E(B-V) ? Interstellar extinction
54- 74 A21 --- Bin Informations about binarity, in refs.dat file
76-137 A62 --- Abun Previous abundance analysis, in refs.dat file
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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- 2 I2 --- Ref Reference number
4- 22 A19 --- BibCode BibCode
24- 43 A20 --- Aut Author's name
47- 82 A36 --- Com Comments
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 I6 --- HD HD number
8- 12 I5 K Teff Effective temperature
14- 16 F3.1 [cm/s2] logg Surface gravity
18- 20 I3 km/s Vsini Rotational velocity
22- 26 F5.2 [-] He ?=- He abundance log(epsilon_He)
28- 31 F4.2 [-] C ?=- C abundance log(epsilon_C)
33- 36 F4.2 [-] N ?=- N abundance log(epsilon_N)
38- 41 F4.2 [-] O ?=- O abundance log(epsilon_O)
43- 46 F4.2 [-] Ne ?=- Ne abundance log(epsilon_Ne)
48- 51 F4.2 [-] Mg ?=- Mg abundance log(epsilon_Mg)
53- 56 F4.2 [-] Al ?=- Al abundance log(epsilon_Al)
58- 61 F4.2 [-] Si ?=- Si abundance log(epsilon_Si)
63- 66 F4.2 [-] P ?=- P abundance log(epsilon_P)
68- 71 F4.2 [-] S ?=- S abundance log(epsilon_S)
73- 76 F4.2 [-] Cl ?=- Cl abundance log(epsilon_Cl)
78- 81 F4.2 [-] Ca ?=- Ca abundance log(epsilon_Ca)
83- 86 F4.2 [-] Sc ?=- Sc abundance log(epsilon_Sc)
88- 91 F4.2 [-] Ti ?=- Ti abundance log(epsilon_Ti)
93- 96 F4.2 [-] V ?=- V abundance log(epsilon_V)
98-101 F4.2 [-] Cr ?=- Cr abundance log(epsilon_Cr)
103-106 F4.2 [-] Mn ?=- Mn abundance log(epsilon_Mn)
108-111 F4.2 [-] Fe ?=- Fe abundance log(epsilon_Fe)
113-116 F4.2 [-] Ni ?=- Ni abundance log(epsilon_Ni)
118-121 F4.2 [-] Ga ?=- Ga abundance log(epsilon_Ga)
123-126 F4.2 [-] Sr ?=- Sr abundance log(epsilon_Sr)
128-131 F4.2 [-] Y ?=- Y abundance log(epsilon_Y)
133-136 F4.2 [-] Zr ?=- Zr abundance log(epsilon_Zr)
138-141 F4.2 [-] Ba ?=- Ba abundance log(epsilon_Ba)
143-144 I2 km/s e_Vsini The error of Vsini
146-149 F4.2 [-] e_He ?=- The error of He abundance
151-154 F4.2 [-] e_C ?=- The error of C abundance
156-159 F4.2 [-] e_N ?=- The error of N abundance
161-164 F4.2 [-] e_O ?=- The error of O abundance
166-169 F4.2 [-] e_Ne ?=- The error of Ne abundance
171-174 F4.2 [-] e_Mg ?=- The error of Mg abundance
176-179 F4.2 [-] e_Al ?=- The error of Al abundance
181-184 F4.2 [-] e_Si ?=- The error of Si abundance
186-189 F4.2 [-] e_P ?=- The error of P abundance
191-194 F4.2 [-] e_S ?=- The error of S abundance
196-199 F4.2 [-] e_Cl ?=- The error of Cl abundance
201-204 F4.2 [-] e_Ca ?=- The error of Ca abundance
206-209 F4.2 [-] e_Sc ?=- The error of Sc abundance
211-214 F4.2 [-] e_Ti ?=- The error of Ti abundance
216-219 F4.2 [-] e_V ?=- The error of V abundance
221-224 F4.2 [-] e_Cr ?=- The error of Cr abundance
226-229 F4.2 [-] e_Mn ?=- The error of Mn abundance
231-234 F4.2 [-] e_Fe ?=- The error of Fe abundance
236-239 F4.2 [-] e_Ni ?=- The error of Ni abundance
241-244 F4.2 [-] e_Ga ?=- The error of Ga abundance
246-249 F4.2 [-] e_Sr ?=- The error of Sr abundance
251-254 F4.2 [-] e_Y ?=- The error of Y abundance
256-259 F4.2 [-] e_Zr ?=- The error of Zr abundance
261-264 F4.2 [-] e_Ba ?=- The error of Ba abundance
266-267 I2 --- o_He ?=- Number of lines for He abundance determination
269-270 I2 --- o_C ?=- Number of lines for C abundance determination
272-273 I2 --- o_N ?=- Number of lines for N abundance determination
275-276 I2 --- o_O ?=- Number of lines for O abundance determination
278-279 I2 --- o_Ne ?=- Number of lines for Ne abundance determination
281-282 I2 --- o_Mg ?=- Number of lines for Mg abundance determination
284-285 I2 --- o_Al ?=- Number of lines for AL abundance determination
287-288 I2 --- o_Si ?=- Number of lines for Si abundance determination
290-291 I2 --- o_P ?=- Number of lines for P abundance determination
293-294 I2 --- o_S ?=- Number of lines for S abundance determination
296-297 I2 --- o_Cl ?=- Number of lines for Cl abundance determination
299-300 I2 --- o_Ca ?=- Number of lines for Ca abundance determination
302-303 I2 --- o_Sc ?=- Number of lines for Sc abundance determination
305-306 I2 --- o_Ti ?=- Number of lines for Ti abundance determination
308-309 I2 --- o_V ?=- Number of lines for V abundance determination
311-312 I2 --- o_Cr ?=- Number of lines for Cr abundance determination
314-315 I2 --- o_Mn ?=- Number of lines for Mn abundance determination
317-319 I3 --- o_Fe ?=- Number of lines for Fe abundance determination
321-322 I2 --- o_Ni ?=- Number of lines for Ni abundance determination
324-325 I2 --- o_Ga ?=- Number of lines for Ga abundance determination
327-328 I2 --- o_Sr ?=- Number of lines for Sr abundance determination
330-331 I2 --- o_Y ?=- Number of lines for Y abundance determination
333-334 I2 --- o_Zr ?=- Number of lines for Zr abundance determination
336-337 I2 --- o_Ba ?=- Number of lines for Ba abundance determination
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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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1- 2 A2 --- El Name of the element
5- 9 F5.2 [-] log(eps)all Average abundance for the entire sample
12- 15 F4.2 [-] e_log(eps)all Standard deviation
17- 21 F5.2 [-] log(eps)nor Average abundance for non-CP stars
24- 27 F4.2 [-] e_log(eps)nor Standard deviations
29- 33 F5.2 [-] log(eps)sun Abundance of the Sun (1)
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Note (1): The solar abundances are taken from Grevesse et al.
(2007SSRv..130..105G 2007SSRv..130..105G)
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Acknowledgements:
Ewa Niemczura, eniem(at)astro.uni.wroc.pl
References:
Morel et al., Paper I 2006A&A...457..651M 2006A&A...457..651M, Cat. J/A+A/457/651
(End) Patricia Vannier [CDS] 27-Oct-2009