Stellar bars reshape the spatial distribution of UV-bright clumps in nearby galaxies

Stellar bars are important drivers of secular evolution in disk galaxies. By redistributing gas and angular momentum, they can influence recent star formation, but their dominant effect on star-forming regions remains uncertain. We investigated how stellar bars affect the radial and azimuthal distributions of star-forming clumps and whether they modify the observed luminosities and sizes of individual clumps. We also examined how these effects depend on host-galaxy stellar mass and bar properties. We analyzed archival HST/WFC3 F275W imaging of 70 barred galaxies and 95 unbarred control galaxies matched in stellar mass, optical color, redshift, and image quality. Using a uniform dendrogram-based method, we identified 95,486 star-forming clumps bright in the ultraviolet. We compared their radial and azimuthal distributions, central F275W emission, and luminosity and size distribution functions. Barred galaxies show a clear deficit of UV-bright clumps at intermediate radii broadly corresponding to the bar region and a local recovery toward the bar ends. Their clumps are also preferentially concentrated along the bar major axis. These spatial differences are stronger in high-mass galaxies. The normalized bar length shows a clearer association with the radial redistribution and central F275W concentration than bar ellipticity, although its relation with the azimuthal distribution is less uniform. When the radius is normalized by bar size, the local recovery occurs near R/R_ ̊m bar suggesting that the bar provides a characteristic spatial scale for the redistribution. Despite these spatial differences, barred and control galaxies have broadly similar clump luminosity and size distribution functions. Stellar bars primarily regulate the spatial distribution of recent star formation on galactic scales rather than substantially changing the observed luminosities and sizes of individual UV clumps. In addition, the strength of this redistribution depends on host-galaxy mass and bar extent.