Tidal Interaction between the UX Tauri A/C Disk System Revealed by ALMA

Luis A. Zapata ... [et al.].

Serie: Trabajos publicados del IAR ; no. 1546

Resumen: We present sensitive and high angular-resolution (∼0"2-0"3)(sub)millimeter (230 and 345 GHz) continuum and CO(2-1)/CO(3-2) linearchive observations of the disk star system in UX Tauri carried outwith the Atacama Large Millimeter/Submillimeter Array. Theseobservations reveal the gas and dusty disk surrounding the young star UXTauri A with a large signal-to-noise ratio (>400 in the continuum and>50 in the line), and for the first time we detect the molecular gasemission associated with the disk of UX Tauri C (with a size for thedisk of <56 au). No (sub)millimeter continuum emission is detected atthe 5σ level (0.2 mJy at 0.85 mm) associated with UX Tauri C. For thecomponent UX Tauri C, we estimate a dust disk mass of ≤0.05M_⊕. Additionally, we report a strong tidal disk interactionbetween both disks, UX Tauri A/C, separated 360 au in projecteddistance. The CO line observations reveal marked spiral arms in the diskof UX Tauri A and an extended redshifted stream of gas associated withthe UX Tauri C disk. No spiral arms are observed in the dust continuumemission of UX Tauri A. Assuming a Keplerian rotation we estimate theenclosed masses (disk+star) from their radial velocities in 1.4 ± 0.6M_☉ for UX Tauri A, and 70 ± 30/sin i Jupiter masses for UXTauri C (the latter coincides with the mass upper limit value for abrown dwarf). The observational evidence presented here lead us topropose that UX Tauri C has a close approach of a possible wide,evolving, and eccentric orbit around the disk of UX Tauri A, causing theformation of spiral arms and a stream of molecular gas falling toward UXTauri C.