Multi-wavelength observations of the young binary system Haro 6-10: The case of misaligned discs

TL;DR

This study uses multi-wavelength high-resolution observations to analyze the young binary system Haro 6-10, revealing highly misaligned circumstellar discs likely formed through cloud fragmentation rather than gravitational capture.

Contribution

It provides detailed insights into the physical and geometrical properties of the circumstellar material in Haro 6-10, highlighting the misalignment of discs and proposing a formation scenario via cloud fragmentation.

Findings

Both components are embedded in a common envelope with interstellar-like dust.

The discs around each star are highly misaligned, with one edge-on and the other face-on.

The system likely formed through molecular cloud fragmentation, not gravitational capture.

Abstract

Context. We present a multi-wavelength, high-resolution observational survey of the young binary system Haro 6-10 (GV Tau, IRAS 04263+2426), which is harbouring one of the few known infrared companions. Aims. The primary goal of this project is to determine the physical and geometrical properties of the circumstellar and circumbinary material in the Haro 6-10 system. Methods. High-resolution optical (HST/WFPC2) and near-infrared (VLT/NACO) images in different bands were analysed to investigate the large-scale structures of the material around the binary.Mid-infrared interferometry (VLTI/MIDI) and spectroscopy (TIMMI2 at the 3.6m ESO telescope) were carried out to determine the structure and optical depth of the circumstellar material around the individual components. Results. The multi-wavelength observations suggest that both components of the binary system Haro 6-10 are embedded in a common envelope. The measured extinction indicates a dust composition of the envelope similar to that of the interstellar medium. Each component of the system has a circumstellar disc-like structure typical of young stars. The discs are highly misaligned: the northern component is seen almost edge-on and the southern component is an almost face-on disc. Conclusions. The two main formation scenarios of binary systems with misaligned discs are the gravitational capture of a passing object in a dense environment, and the fragmentation of the collapsing molecular cloud. Given the low-density environment of the Taurus-Aurigae star-forming region, the first scenario is unlikely for Haro 6-10. The binary system most probably formed via fragmentation of two different parts of the collapsing molecular cloud combined with other dynamical processes related to the cloud and/or the protostars. This can be the explanation also for other binary systems with an infrared companion.