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Observations of First Hydrostatic Core candidates, a theoretically predictedevolutionary link between the prestellar and protostellar phases, are vital forprobing the earliest phases of star formation. We aim to determine thedynamical state of the First Hydrostatic Core candidate Cha-MMS1. We observedCha-MMS1 in various transitions with the APEX and Mopra telescopes. Themolecular emission was modeled with a radiative transfer code to deriveconstraints on the envelope kinematics. We derive an internal luminosity of0.08 - 0.18 Lsol. An average velocity gradient of 3.1(0.1) km/s/pc over 0.08 pcis found perpendicular to the filament in which Cha-MMS1 is embedded. Thegradient is flatter in the outer parts and at the innermost 2000 - 4000 AU.These features suggest solid-body rotation beyond 4000 AU and slower,differential rotation beyond 8000 AU. The origin of the flatter gradient in theinnermost parts is unclear. The classical infall signature is detected in HCO+3-2 and CS 2-1. The radiative transfer modeling indicates a uniform infallvelocity in the outer parts of the envelope. An infall velocity field scalingwith r^(-0.5) is consistent with the data for r < 9000 AU. The infallvelocities are 0.1 - 0.2 km/s at r > 3300 AU and 0.04 - 0.6 km/s at r < 3300AU. Both the internal luminosity of Cha-MMS1 and the infall velocity field inits envelope are consistent with predictions of MHD simulations for the firstcore phase. There is no evidence for a fast, large-scale outflow stemming fromCha-MMS1 but excess emission from the high-density tracers CS 5-4, CO 6-5, andCO 7-6 suggests the presence of higher-velocity material at the inner core. Itsinternal luminosity excludes Cha-MMS1 being a prestellar core. The kinematicalproperties of its envelope are consistent with Cha-MMS1 being a first corecandidate or a very young Class 0 protostar.(abridged).

The dynamical state of the First Hydrostatic Core Candidate Cha-MMS1