Measurements of binary stars with coherent integration of NPOI data

TL;DR

This paper demonstrates that using only the phase of complex visibility from NPOI data allows precise measurement of binary star properties such as separation, orientation, and brightness ratio across wavelengths, avoiding calibration issues.

Contribution

It introduces a phase-only coherent integration method for binary star measurements, improving accuracy over amplitude-based techniques.

Findings

Baseline phase can accurately determine binary star parameters.

Phase-only measurements avoid calibration errors inherent in amplitude data.

Method works across different wavelengths.

Abstract

In this paper we use coherently integrated visibilities (see separate paper in these proceedings, Jorgensen et al. 2008) to measure the properties of binary stars. We use only the phase of the complex visibility and not the amplitude. The reason for this is that amplitudes suffer from the calibration effect (the same for coherent and incoherent averages) and thus effectively provide lower accuracy measurements. We demonstrate that the baseline phase alone can be used to measure the separation, orientation and brightness ratio of a binary star, as a function of wavelength.