Regulus observed with VLTI/AMBER

TL;DR

This paper reports the first high spectral resolution differential interferometry observations of Regulus A using VLTI/AMBER, confirming previous results and opening questions about gravity darkening effects.

Contribution

It introduces the application of differential interferometry at high spectral resolution to observe Regulus A, providing new insights and confirming prior findings.

Findings

Confirmed previous interferometry results within uncertainties

Demonstrated the feasibility of high spectral resolution differential interferometry

Identified open questions regarding gravity darkening effects

Abstract

The rapidly rotating primary component of Regulus A system has been observed, for the first time, using the technique of differential interferometry at high spectral resolution. The observations have been performed across the Br$_\gamma$ spectral line with the VLTI/AMBER focal instrument in high spectral resolution mode (R $\approx$ 12000) at $\approx$ 80-130m (projected on the sky) Auxiliary Telescopes triplet baseline configurations. We confirm, within the uncertainties, the results previously obtained using the techniques of classical long-baseline interferometry, although the question of anomalous gravity darkening remains open for the future study.