J/A+A/472/241 UV Flux distributions of gamma Dor stars (Gerbaldi+, 2007)
UV Flux distributions of gamma Dor stars.
Gerbaldi M., Faraggiana R., Caffau E.
<Astron. Astrophys. 472, 241 (2007)>
=2007A&A...472..241G 2007A&A...472..241G
ADC_Keywords: Stars, variable ; Binaries, spectroscopic ; Stars, atmospheres
Keywords: stars: atmosphere - stars: binaries: spectroscopic -
stars: variable: general - stars: peculiar
Abstract:
It seems that the recently identified class of pulsating stars,
the gamma Dor type-variables, includes objects with different
metal abundances and a large percentage of binaries. We looked for
indicators of metal abundance peculiarities and stellar binarity in
a sample of 40 confirmed gamma Dor stars. Absolute magnitudes from
Hipparcos parallaxes and UV magnitudes, from the S2/S68 experiment on
board the TD1 satellite, are retrieved from databases and compared
with predicted values. A set of non variable normal stars is used to
check the consistency of this analysis and also serve as reference
stars. Twenty-nine stars of the gamma Dor star sample, which is 73%
of it, are discovered having abnormal UV fluxes constantly showing
UV flux excesses compared to those computed with the atmospheric
parameters (Teff, logg, and metallicity) determined from calibration
of the uvbyBeta indices. The reason for this UV excess of flux at
196.5nm and at 236.5nm, which was previously known only for HD 209295,
cannot be ascribed to binarity alone. An extra source of UV flux or
less UV absorption - yet unknown - must be present.
Description:
Reddening and atmospheric parameters (Teff, logg, metallicity, and
visual absolute magnitude) for the gamma Dor stars and a set of
reference stars.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 182 40 Reddening and atmospheric parameters for the
gamma Dor stars
table2.dat 42 41 Reddening and atmospheric parameters for a
sample of reference stars
table3.dat 28 10 Visual magnitude for the 10 SB2 or close VB
gamma Dor stars
notes.dat 80 15 Individual notes
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See also:
J/A+A/450/715 : Differential uvby photometry of HD 218427 (Rodriguez+, 2006)
J/A+A/456/261 : Differential uvby photometry of HD 239276 (Rodriguez+, 2006)
Byte-by-byte Description of file: table[12].dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- HD HD number (1)
8- 9 A2 --- n_HD [no] "no" indicates star without Beta-index
measurement
11- 16 F6.3 mag E(b-y) Reddening computed with the Moon program (2)
18- 21 I4 K Teff1 Effective temperature computed with the
Moon & Dworetsky program (MD) (2)
23- 26 F4.2 [cm/s2] logg1 Surface gravity computed with the
Moon & Dworetsky program (MD) (2)
28- 31 I4 K Teff2 ? Effective temperature computed with the
Kunzli et al. program (Gen) (2)
33- 36 F4.2 [cm/s2] logg2 ? Surface gravity computed with the
Kunzli et al. program (Gen) (2)
38- 42 F5.2 [Sun] [M/H] ? Metallicity computed with the
Kunzli et al. program (Gen) (2)
44- 47 F4.2 mag VMAG1 ? Visual absolute magnitude photometrically
derived using calibration of uvbyBeta
photometry adopted by Moon (1985) (2)
49- 52 F4.2 mag VMAG0 ? Visual absolute magnitude derived using
Hipparcos parallaxes
54 A1 --- Note [abcd] Note about binarity (3)
56-182 A127 --- Rem Remarks (4)
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Note (1):
In the case of a binary system, the gamma Dor is the A component,
except for HD 221866 where the gamma Dor star is likely to be the
B component.
For the SB2 stars, HD 86371 and HD 113867, it is not clear
which component is the gamma Dor variable (Henry & Fekel,
2003AJ....126.3058H 2003AJ....126.3058H); in fact, both components could pulsate
(Henry et al., 2005, Cat. J/AJ/129/2815)
Note (2): Program references as follows:
Moon (1985) = Moon program, 1985, Comm. from the Univ of London Obs.
78 and revision in 1985, private comm.
MD = Moon & Dworetsky, 1985MNRAS.217..305M 1985MNRAS.217..305M
Gen = Kunzli et al., 1997A&AS..122...51K 1997A&AS..122...51K
Note (3): For the individual components of the SB2 systems the Vmag and
the spectral types are taken as follows:
a = Henry & Fekel (2002PASP..114..988H 2002PASP..114..988H) and Faraggiana & Gerbaldi
(2004ASPC..318..316F 2004ASPC..318..316F). For HD 108100 there is a controversy on
its SB2 nature (Henry & Fekel (2002PASP..114..988H 2002PASP..114..988H) and
Faraggiana & Gerbaldi (2004ASPC..318..316F 2004ASPC..318..316F).
b = Henry & Fekel, 2003AJ....126.3058H 2003AJ....126.3058H
c = Henry et al. (2005AJ....129.2815H 2005AJ....129.2815H)
d = Kaye et al. (2004PASP..116..558K 2004PASP..116..558K) and
Fekel et al. (2003AJ....125.2196F 2003AJ....125.2196F).
Note (4): The remarks are from Henry et al. (2005, Cat. J/AJ/129/2815)
complemented by duplicity detection from the Hipparcos Catalogue
(1997, Cat. I/239), the Washington Visual Double Star Catalogue
(WDS, 1997, Cat. I/237) and the Fourth catalogue of interferometric
measurements (Hartkopf et al., 2003,
http://ad.usno.navy.mil/wds/int4.html). In case of several values of
the separation taken from WDS, the smallest one is retained.
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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- 6 I6 --- HD HD number
10- 13 F4.2 mag Vmag V-Johnson magnitude from the Hipparcos
Catalogue (Cat. I/239)
16- 19 F4.2 mag V(A) ? V-Johnson magnitude for the component A
22- 26 F5.2 mag V(B) ? V-Johnson magnitude for the component B
28 A1 --- n_HD [*] * indicates a note in notes.dat file
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Byte-by-byte Description of file: notes.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- HD HD number
8- 80 A73 --- Note Note
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Acknowledgements:
Michele Gerbaldi, gerbaldi(at)iap.fr
(End) Patricia Vannier [CDS] 15-Jun-2007