GG Tau: the fifth element

Abstract

We aim at unveiling the observational imprint of physical mechanisms that govern planetary formation in young, multiple systems. In particular, we investigate the impact of tidal truncation on the inner circumstellar disks. We observed the emblematic system GG Tau at high-angular resolution: a hierarchical quadruple system composed of low-mass T Tauri binary stars surrounded by a well-studied, massive circumbinary disk in Keplerian rotation. We used the near-IR 4-telescope combiner PIONIER on the VLTI and sparse-aperture-masking techniques on VLT/NaCo to probe this proto-planetary system at sub-AU scales. We report the discovery of a significant closure-phase signal in H and Ks bands that can be reproduced with an additional low-mass companion orbiting GG Tau Ab, at a (projected) separation rho = 31.7 +/- 0.2mas (4.4 au) and PA = 219.6 +/- 0.3deg. This finding offers a simple explanation for several key questions in this system, including the missing-stellar-mass problem and the asymmetry of continuum emission from the inner dust disks observed at millimeter wavelengths. Composed of now five co-eval stars with 0.02 <= Mstar <= 0.7 Msun, the quintuple system GG Tau has become an ideal test case to constrain stellar evolution models at young ages (few 10^6yr).

5pages, 3 figures, 1 appendix (online material)

References in corpus (3)

• The Transiting Circumbinary Planets Kepler-34 and Kepler-35
• Few Skewed Disks Found in First Closure-Phase Survey of Herbig Ae/Be stars
• The inner radius of T Tauri disks estimated from near-infrared interferometry: the importance of scattered light

Cited by in corpus (5)

• Dynamical Masses of Low Mass Stars in the Taurus and Ophiuchus Star Forming Regions
• Multiplicity and clustering in Taurus star-forming region. I. Unexpected ultra-wide pairs of high-order multiplicity in Taurus
• Planets Around Low-Mass Stars (PALMS). V. Age-Dating Low-Mass Companions to Members and Interlopers of Young Moving Groups
• Circumbinary Ring, Circumstellar disks and accretion in the binary system UY Aurigae
• Testing dust trapping in the circumbinary disk around GG Tau A