Context : Red supergiant stars possess surface features and extended molecular atmospheres .
Photospheric convection may be a crucial factor of the levitation of the outer atmospheric layers .
However , the mechanism responsible is still poorly understood .

Aims : We image the stellar surface of V602 Carinae ( V602 Car ) to constrain the morphology and contrast of the surface features and of the extended atmospheric layers .

Methods : We observed V602 Car with the Very Large Telescope Interferometer ( VLTI ) PIONIER instrument ( 1.53-1.78 \mathrm { \mu } m ) between May and July 2016 , and April and July 2019 with different telescope configurations .
We compared the image reconstructions with 81 temporal snapshots of 3D radiative-hydrodynamics ( RHD ) CO ^ { 5 } BOLD simulations in terms of contrast and morphology , using the Structural Similarity Index .

Results : The interferometric data are compatible with an overall spherical disk of angular diameter 4.4 \pm 0.2 mas , and an extended molecular layer .
In 2016 , the reconstructed image reveals a bright arc-like feature toward the northern rim of the photospheric surface .
In 2019 , an arc-like feature is seen at a different orientation and a new peak of emission is detected on the opposite side .
The contrasts of the reconstructed surface images are 11 % \pm 2 % and 9 % \pm 2 % for 2016 and 2019 , respectively .
The morphology and contrast of the two images are consistent with 3D RHD simulations , within our achieved spatial resolution and dynamic range .
The extended molecular layer contributes 10–13 % of the total flux with an angular diameter of 6–8 mas .
It is present but not clearly visible in the reconstructed images because it is close to the limits of the achieved dynamic range .
The presence of the molecular layer is not reproduced by the 3D RHD simulations .

Conclusions:3D RHD simulations predict substructures similar to the observed surface features of V602 Car at two different epochs .
We interpret the structure on the stellar surface as being related to instationary convection .
This structure is further convolved to larger observed patches on the stellar surface with our observational spatial resolution .
Even though the simulations reproduce the observed features on the stellar surface , convection alone may not be the only relevant process that is levitating the atmosphere .