  High angular resolution observations of young stellar objects are required to
study the inner astronomical units of protoplanetary disks in which the
majority of planets form. As they evolve, gaps open up in the inner disk
regions and the disks are fully dispersed within ~10 Myrs. MWC 614 is a
pre-transitional object with a ~10au radius gap. We present a set of high
angular resolution observations of this object including SPHERE/ZIMPOL
polarimetric and coronagraphic images in the visible, KECK/NIRC2 near-infrared
aperture masking observations and VLTI (AMBER, MIDI, and PIONIER) and CHARA
(CLASSIC and CLIMB) long-baseline interferometry at infrared wavelengths. We
find that all the observations are compatible with an inclined disk (i ~55deg
at a position angle of ~20-30deg). The mid-infrared dataset confirms the disk
inner rim to be at 12.3+/-0.4 au from the central star. We determined an upper
mass limit of 0.34 Msun for a companion inside the cavity. Within the cavity,
the near-infrared emission, usually associated with the dust sublimation
region, is unusually extended (~10 au, 30 times larger than the theoretical
sublimation radius) and indicates a high dust temperature (T~1800 K). As a
possible result of companion-induced dust segregation, quantum heated dust
grains could explain the extended near-infrared emission with this high
temperature. Our observations confirm the peculiar state of this object where
the inner disk has already been accreted onto the star exposing small particles
inside the cavity to direct stellar radiation.
