Leo T is a gas-rich dwarf located at 414 { kpc } ( 1.4 R _ { vir } ) distance from the Milky Way ( MW ) and it is currently assumed to be on its first approach .
Here , we present an analysis of orbits calculated backward in time for the dwarf with our new code delorean , exploring a range of systematic uncertainties , e.g . MW virial mass and accretion , M31 potential , and cosmic expansion .
We discover that orbits with tangential velocities in the Galactic Standard-of-Rest frame lower than | \vec { u } _ { t } ^ { GSR } | \leq 63 ^ { +47 } _ { -39 } { km } { s } ^ { -1 } result in backsplash solutions , i.e .
orbits that entered and left the MW dark matter halo in the past , and that velocities above | \vec { u } _ { t } ^ { GSR } | \geq 21 ^ { +33 } _ { -21 } { km } { s } ^ { -1 } result in wide orbit backsplash solutions with a minimum pericenter range of D _ { min } \geq 38 ^ { +26 } _ { -16 } { kpc } , which would allow this satellite to survive gas stripping and tidal disruption .
Moreover , new proper motion estimates match with our region of backsplash solutions .
We applied our method to other distant MW satellites , finding a range of gas stripped backsplash solutions for the gas-less Cetus and Eridanus II , providing a possible explanation for their lack of cold gas , while only first in-fall solutions are found for the H I rich Phoenix I .
We also find that the cosmic expansion can delay their first pericenter passage when compared to the non-expanding scenario .
This study explores the provenance of these distant dwarfs and provides constraints on the environmental and internal processes that shaped their evolution and current properties .