Volume 559, November 2013
|Number of page(s)||5|
|Section||Celestial mechanics and astrometry|
|Published online||19 November 2013|
Improved VLBI measurement of the solar system acceleration⋆
1 Geoscience Australia, PO Box 378, 2601 Canberra, Australia
2 Observatoire de Paris, SYRTE, CNRS, UPMC, GRGS, 75014 Paris, France
Received: 30 April 2013
Accepted: 8 October 2013
Aims. We propose new estimates of the secular aberration drift, which is mainly caused by the rotation of the solar system about the Galactic center, based on up-to-date VLBI observations and improved method of outlier elimination.
Methods. We fitted degree-2 vector spherical harmonics to the extragalactic radio source proper motion field derived from geodetic VLBI observations during 1979–2013. We paid particular attention to the outlier elimination procedure that removes outliers from (i) radio source coordinate time series and (ii) the proper motion sample.
Results. We obtain more accurate values of the Solar system acceleration than in our previous paper. The acceleration vector is oriented towards the Galactic center within ~7°. The component perpendicular to the Galactic plane is statistically insignificant. We show that an insufficient cleaning of the data set can lead to strong variations in the dipole amplitude and orientation, and hence to statistically biased results.
Key words: astrometry / reference systems
Proper motion data used for the DR solution is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (220.127.116.11) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/559/A95
© ESO, 2013
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