Tidal Interaction between the UX Tauri Disk A/C System Revealed by ALMA
  We present sensitive and high angular resolution ($\sim$0.2-0.3$''$)
(sub)millimeter (230 and 345 GHz) continuum and CO(2$-$1)/CO(3$-$2) line
archive observations of the disk star system in UX Tauri carried out with ALMA
(The Atacama Large Millimeter/Submillimeter Array). These observations reveal
the gas and dusty disk surrounding the young star UX Tauri A with a large
signal-to-noise ratio ($>$400 in the continuum and $>$50 in the line), and for
the first time is detected the molecular gas emission associated with the disk
of UX Tauri C (with a size for the disk of $<$56 au). No (sub)millimeter
continuum emission is detected at 5$\sigma$-level (0.2 mJy at 0.85 mm)
associated with UX Tauri C. For the component UX Tauri C, we estimate a dust
disk mass of $\leq$ 0.05 M$_\oplus$. Additionally, we report a strong tidal
disk interaction between both disks UX Tauri A/C, separated 360 au in projected
distance. The CO line observations reveal marked spiral arms in the disk of UX
Tauri A and an extended redshifted stream of gas associated with the UX Tauri C
disk. No spiral arms are observed in the dust continuum emission of UX Tauri A.
Assuming a Keplerian rotation we estimate the enclosed masses (disk$+$star)
from their radial velocities in 1.4 $\pm$ 0.6 M$_\odot$ for UX Tauri A, and 70
$\pm$ 30 / $\sin i$ Jupiter masses for UX Tauri C (the latter coincides with
the mass upper limit value for a brown dwarf). The observational evidence
presented here lead us to propose that UX Tauri C is having a close approach of
a possible wide, evolving and eccentric orbit around the disk of UX Tauri A
causing the formation of spiral arms and the stream of molecular gas falling
towards UX Tauri C.
