Access to Astronomical Catalogues

← Click to display the menu
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
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:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 182 40 Reddening and atmospheric parameters for the gamma Dor stars table2.dat 182 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
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
Bytes Format Units Label Explanations
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)
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); 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 Gen = Kunzli et al., 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) and Faraggiana & Gerbaldi (2004ASPC..318..316F). For HD 108100 there is a controversy on its SB2 nature (Henry & Fekel (2002PASP..114..988H) and Faraggiana & Gerbaldi (2004ASPC..318..316F). b = Henry & Fekel, 2003AJ....126.3058H c = Henry et al. (2005AJ....129.2815H) d = Kaye et al. (2004PASP..116..558K) and Fekel et al. (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.
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
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
Byte-by-byte Description of file: notes.dat
Bytes Format Units Label Explanations
1- 6 I6 --- HD HD number 8- 80 A73 --- Note Note
Acknowledgements: Michele Gerbaldi, gerbaldi(at)iap.fr
(End) Patricia Vannier [CDS] 15-Jun-2007
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

catalogue service

© UDS/CNRS

Contact