The Carina dwarf spheroidal is one of the Milky Way's most studied companions, and its stars refuse to behave like a simple pressure-supported ball. Spectroscopic campaigns find hints of internal velocity gradients, stars in different regions drifting at slightly different line-of-sight velocities, alongside kinematic substructures and an unusually episodic star formation history that built distinct stellar populations in separated bursts (Munoz et al. 2006; Fabrizio et al. 2011).
In ΛCDM, Carina is a dark-matter-dominated dwarf spheroidal: a dispersion-supported stellar population sitting in an isothermal CDM halo, where ordered rotation should be negligible and kinematic complexity should be erased by the dominant random motions. The observed gradients therefore need external causes, tidal stirring by the Milky Way being the leading candidate, but tides strong enough to torque the kinematics require close orbital passages that threaten the galaxy's survival and conflict with its apparently intact structure, forcing finely tuned orbits and halo shapes to let Carina be both stirred and unharmed (Lokas 2009; Battaglia and Starkenburg 2012). The chemodynamical patterns, different populations with different kinematics, compound the modeling burden.
The standing is a precision-kinematics frontier: the gradients sit near current measurement limits, and Gaia proper motions plus next-generation spectroscopy of thousands of member stars will decide whether Carina genuinely rotates, and around which axis.