We report multi-epoch VLBI H _ { 2 } O maser observations towards the compact cluster of YSOs close to the Herbig Be star LkH \alpha 234 .
This cluster includes LkH \alpha 234 and at least nine more YSOs that are formed within projected distances of \sim 10 arcsec ( \sim 9,000 au ) .
We detect H _ { 2 } O maser emission towards four of these YSOs .
In particular , our VLBI observations ( including proper motion measurements ) reveal a remarkable very compact ( \sim 0.2 arcsec = \sim 180 au ) , bipolar H _ { 2 } O maser outflow emerging from the embedded YSO VLA 2 .
We estimate a kinematic age of \sim 40 yr for this bipolar outflow , with expanding velocities of \sim 20 km s ^ { -1 } and momentum rate \dot { M } _ { w } V _ { w } \simeq 10 ^ { -4 } -10 ^ { -3 } M _ { \odot } yr ^ { -1 } km s ^ { -1 } \times ( \Omega / 4 \pi ) , powered by a YSO of a few solar masses .
We propose that the outflow is produced by recurrent episodic jet ejections associated with the formation of this YSO .
Short-lived episodic ejection events have previously been found towards high-mass YSOs .
We show now that this behaviour is also present in intermediate-mass YSOs .
These short-lived episodic ejections are probably related to episodic increases in the accretion rate , as observed in low-mass YSOs .
We predict the presence of an accretion disk associated with VLA 2 .
If detected , this would represent one of the few known examples of intermediate-mass stars with a disk-YSO-jet system at scales of a few hundred au .