Analysing weak orbital signals in Gaia data

作者：Lucy L B^*

来源：Astronomy & Astrophysics, 2014, 571: A86.

DOI：10.1051/0004-6361/201424405

• binaries: visual
• stars: fundamental parameters
• methods: statistical

Anomalous orbits are found when minimum-chi(2) estimation is applied to synthetic Gala data for orbits with astrometric signatures comparable to the single-scan measurement error (Pourbaix 2002, A&A, 385, 686). These orbits are nearly parabolic, edge-on, and their major axes align with the line-of-sight to the observer. Such orbits violate the Copernican principle (CPO and as such could be rejected. However, the preferred alternative is to develop a statistical technique that incorporates the CPr as a fundamental postulate. This can be achieved in a Bayesian context by defining a Copernican prior. Pourbaix's anomalous orbits then no longer arise. Instead, the selected orbits have a somewat higher chi(2) but do not violate the CPr. The problem of detecting a weak additional orbit in an astrom.etric binary with a well-determined orbit is also treated.

• 出版日期2014-11