The chemodynamical memory of a major merger in a NIHAO-UHD Milky Way analogue – II. Were Splash stars heated or already born hot?

One of the most debated consequences of the Milky Way’s last major merger is the so-called Splash: stars with disc-like chemistry but halo-like kinematics, often interpreted as evidence for the violent heating of an early protodisc. Using the same high-resolution NIHAO-UHD cosmological simulation an