  The physical conditions leading the sunspot penumbra decay are poorly
understood so far. We investigate the photospheric magnetic and velocity
properties of a sunspot penumbra during the decay phase to advance the current
knowledge of the conditions leading to this process. A penumbral decay was
observed with the CRISP instrument at the Swedish 1m Solar Telescope on 2016
September 4 and 5 in active region NOAA 12585. During these days, full-Stokes
spectropolarimetric scans along the Fe I 630 nm line pair were acquired over
more than one hour. We inverted these observations with the VFISV code in order
to obtain the evolution of the magnetic and velocity properties. We complement
the study with data from instruments onboard the Solar Dynamics Observatory and
Hinode space missions. The studied penumbra disappears progressively in both
time and space. The magnetic flux evolution seems to be linked to the presence
of Moving Magnetic Features (MMFs). Decreasing Stokes V signals are observed.
Evershed flows and horizontal fields were detected even after the disappearance
of the penumbral sector. The analyzed penumbral decay seems to result from the
interaction between opposite polarity fields in type III MMFs and penumbra,
while the presence of overlying canopies rules the evolution in the different
penumbral sectors.
