Accretion process, magnetic fields, and apsidal motion in the pre-main sequence binary DQ Tau

Abstract

Classical T Tauri stars (CTTSs) are young stellar objects that accrete materials from their accretion disc influenced by their strong magnetic field. The magnetic pressure truncates the disc at a few stellar radii and forces the material to leave the disc plane and fall onto the stellar surface by following the magnetic field lines. However, this global scheme may be disturbed by the presence of a companion interacting gravitationally with the accreting component. This work is aiming to study the accretion and the magnetic field of the tight eccentric binary DQ Tau, composed of two equal-mass ($\sim$ 0.6 \msun ) CTTSs interacting at different orbital phases. We investigated the variability of the system using a high-resolution spectroscopic and spectropolarimetric monitoring performed with ESPaDOnS at the CFHT. We provide the first ever magnetic field analysis of this system, the Zeeman-Doppler imaging revealed a stronger magnetic field for the secondary than the primary (1.2 kG and 0.5 kG, respectively), but the small-scale fields analysed through Zeeman intensification yielded similar strengths (about 2.5 kG). The magnetic field topology and strengths are compatible with the accretion processes on CTTSs. Both components of this system are accreting, with a change of the main accretor during the orbital motion. In addition, the system displays a strong enhancement of the mass accretion rate at periastron and apastron. We also discovered, for the first time in this system, the apsidal motion of the orbital ellipse.

18 pages, 20 figures. Accepted for publication in MNRAS

References in corpus (13)

• A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
• X-Shooter spectroscopy of young stellar objects in Lupus: Accretion properties of class II and transitional objects
• An Optical Spectroscopic Study of T Tauri Stars. I. Photospheric Properties
• Magnetospheric accretion-ejection processes in the classical T Tauri star AA
• Magnetic fields of M dwarfs
• Magnetic field topology of the unique chemically peculiar star CU Virginis
• Magnetic fields and chemical peculiarities of the very young intermediate-mass binary system HD 72106
• Accretion and Magnetic Reconnection in the Classical T Tauri Binary DQ Tau
• Magnetic Field of the Eclipsing M Dwarf Binary YY Gem
• The Inner Disk and Accretion Flow of the Close Binary DQ Tau
• The large-scale magnetic field of the eccentric pre-main-sequence binary system V1878 Ori
• Small-scale magnetic fields of the spectroscopic binary T Tauri stars V1878 Ori and V4046 Sir
• The Interior Structure Constants as an Age Diagnostic for Low-Mass, Pre-Main Sequence Detached Eclipsing Binary Stars