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J/A+A/597/A137    HD 123999 and Alpha Cen A and B OIFITS files (Kervella+, 2017)

The radii and limb darkenings of Alpha Centauri A and B. Kervella P., Bigot L., Gallenne A., Thevenin F. <Astron. Astrophys. 597, A137 (2017)> =2017A&A...597A.137K (SIMBAD/NED BibCode)
ADC_Keywords: Interferometry ; Stars, bright ; Stars, double and multiple Keywords: stars: individual: alpha Centauri - techniques: interferometric - stars: solar-type - stars: fundamental parameters - stars: binaries: visual Abstract: The photospheric radius is one of the fundamental parameters governing the radiative equilibrium of a star. We report new observations of the nearest solar-type stars Alpha Centauri A (G2V) and B (K1V) with the VLTI/PIONIER optical interferometer. The combination of four configurations of the VLTI enable us to measure simultaneously the limb darkened angular diameter thetaLD and the limb darkening parameters of the two solar-type stars in the near-infrared H band (lambda=1.65um). We obtain photospheric angular diameters of θLD(A)=8.502±0.038mas (0.43%) and θLD(B)=5.999±0.025mas (0.42%), through the adjustment of a power law limb darkening model. We find H band power law exponents of α(A)=0.1404±0.0050 (3.6%) and α(B)=0.1545±0.0044 (2.8%), which closely bracket the observed solar value (alpha=0.15027). Combined with the parallax pi=747.17±0.61mas determined by Kervella et al. (2016), we derive linear radii of RA=1.2234±0.0053R (0.43%) and RB=0.8632±0.0037R (0.43%). The power law exponents that we derive for the two stars indicate a significantly weaker limb darkening than predicted by both 1D and 3D stellar atmosphere models. As this discrepancy is also observed on the near-infrared limb darkening profile of the Sun, an improvement of the calibration of stellar atmosphere models is clearly needed. The reported PIONIER visibility measurements of Alpha Cen A and B provide a robust basis to validate the future evolutions of these models. Description: The files contain all the PIONIER calibrated interferometric data obtained on Alpha Centauri A and B, as well as on the dimensional calibrator HD 123999. The data files follow the OIFITS standard of optical interferometry as defined by Pauls et al. (2005PASP..117.1255P). Objects: ---------------------------------------------------------- RA (2000) DE Designation(s) ---------------------------------------------------------- 14 10 23.93 +25 05 30.0 HD 123999 = * 12 Boo 14 39 36.49 -60 50 02.4 alpha Cen A = HD 128620 14 39 35.06 -60 50 15.1 alpha Cen B = HD 128621 ---------------------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file list.dat 139 13 List of OIFITS files oifits/* 0 13 Individual OIFITS files
See also: J/A+A/586/A35 : TZ For OIFITS files (Gallenne+, 2016) Byte-by-byte Description of file: list.dat
Bytes Format Units Label Explanations
1- 11 A11 --- Name Star name 13- 21 F9.5 deg RAdeg OI target right ascension (J2000) 23- 31 F9.5 deg DEdeg OI target declination (J2000) 33- 36 I4 km EffWave1 First Effective wavelength 38- 41 I4 km EffWave2 Second Effective wavelength 43- 46 I4 km EffWave3 Third Effective wavelength 48- 51 I4 km EffWave4 Fourth Effective wavelength 53- 56 I4 km EffWave5 Fith Effective wavelength 58- 61 I4 km EffWave6 sixth Effective wavelength 63- 66 F4.1 km EffBand Effective band 68- 69 I2 Kibyte size Size of OIFITS file 71- 95 A25 --- FileName Name of OIFITS file, in subdirectory oifits 97-139 A43 --- Title Title of the OIFITS file
Acknowledgements: Pierre Kervella, pierre.kervella(at)obspm.fr
(End) Patricia Vannier [CDS] 12-Oct-2016
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

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