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J/A+A/444/941      Effective temperature of B stars             (Paunzen+, 2005)

An empirical temperature calibration for the Δa photometric system. I. The B-type stars. Paunzen E., Schnell A., Maitzen H.M. <Astron. Astrophys., 444, 941-946 (2005)> =2005A&A...444..941P
ADC_Keywords: Stars, B-type ; Effective temperatures ; Photometry Keywords: stars: chemically peculiar - stars: early-type - techniques: photometric Abstract: We establish an empirical effective temperature calibration of main sequence, luminosity class V to III B-type stars for the Delta a photometric system which was originally developed to detect magnetic chemically peculiar objects of the upper main sequence (early B-type to early F-type) at 5200A. However, this system provides the index g1-y which shows an excellent correlation with B-V as well as b-y and can be used as an indicator of the effective temperature. This is supplemented by a very accurate color-magnitude diagram, y or V versus g1-y, which can be used, for example, to determine the reddening, distance and age of an open cluster. This makes the Delta a photometric system an excellent tool to investigate the HR diagram in more detail. Using the reddening-free parameters and already established calibrations within the Stromgren uvbybeta, Geneva 7-color and Johnson UBV systems, a polynomial fit of third degree for the averaged effective temperatures to the individual (g1-y)0 values was derived. For this purpose, data from the literature as well as new observations were taken resulting in 225 suitable bright normal B-type objects. The statistical mean of the error for this sample is 238K which is sufficient to investigate the HRD of distant galactic open clusters as well as extragalactic aggregates in the future. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 76 225 *List of 225 normal type stars used for the calibration
Note on table2.dat: see Geneva GCPD/75 for a short description of the Maitzen photometric system (1976A&A....51..223M)
See also: J/A+A/391/1039 : Teff of metal-poor A-type stars (Kinman+, 2002) J/A+A/411/559 : Teff for 181 F-K dwarfs (Kovtyukh+, 2003) J/A+A/429/235 : Teff of 119 C-rich giants (Bergeat+, 2005) J/A+A/442/281 : Late-type giants BVRIJHKL and Teff calibration (Kucinskas+, 2005) J/A+AS/117/227 : Dwarf effective temperatures (Alonso+ 1996) J/A+AS/122/131 : Delta Scuti rotational velocities and Teff (Solano+ 1997) J/ApJ/626/446 : Teff scale of FGK stars (Ramirez+, 2005) J/other/BSAO/38.152 : Teff of CP stars (Glagolevskij 1994) Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 6 I6 --- HD HD number 8- 11 I4 --- HR HR number 13- 19 F7.3 mag Vmag V magnitude 20- 26 F7.3 mag u-b Stroemgren u-b colour index 27- 33 F7.3 mag X Geneva reddenning-free parameter X 34- 40 F7.3 mag (B-V)0 (B-V)0 colour index 41- 47 F7.3 mag (g1-y)0 (g1-y)0 colour index 48- 53 I6 K Teff Adopted effective temperature 55- 58 I4 K e_Teff Error of the adopted Teff 60- 71 A12 --- SpType MK spectral type 72- 76 I5 km/s vsini ?=-99 vsini (1)
Note (1): Magic number -99 mean no available data
Acknowledgements: Ernst Paunzen, ernst.paunzen(at) History: * 17-Dec-2005: Original version * 13-Sep-2006: V magnitude of HD 62578 corrected into 5.572 (email from author)
(End) E. Paunzen (IfA, Vienna), Patricia Vannier [CDS] 17-Dec-2005
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