We present radial velocities for five member stars of the recently discovered young ( age \simeq 100 - 150 Myr ) stellar system Price-Whelan 1 ( PW 1 ) , that is located far away in the Galactic Halo ( D \simeq 29 kpc , Z \simeq 15 kpc ) , and that is probably associated to the Leading Arm ( LA ) of the Magellanic Stream .
We measure the systemic radial velocity of PW 1 , V _ { r } = 275 \pm 10 km/s , significantly larger than the velocity of the LA gas in the same direction .
We re-discuss the main properties and the origin of this system in the light of these new observations , computing the orbit of the system and comparing its velocity with that of the \ion Hi in its surroundings .
We show that the bulk of the gas at the velocity of the stars is more than 10 \degr ( 5 kpc ) away from PW 1 and the velocity difference between the gas and the stars become larger as gas closer to the stars is considered .
We discuss the possibilities that ( a ) the parent gas cloud was dissolved by the interaction with the Galactic gas , and ( b ) that the parent cloud is the high velocity cloud HVC 287.5+22.5+240 , lagging behind the stellar system by \simeq 25 km/s and \simeq 10 \degr \simeq 5 kpc .
This HVC , that is part of the LA , has metallicity similar to PW 1 , displays a strong magnetic field that should help to stabilise the cloud agains ram pressure , and shows traces of molecular hydrogen .
We also show that the system is constituted of three distinct pieces that do not differ only by position in the sky but also by stellar content .