Disks around Young Planetary-mass Objects: Ultradeep Spitzer Imaging of NGC 1333

We report on a sensitive infrared search for disks around isolated young planetary-mass objects (PMOs) in the NGC1333 cluster, by stacking 70 Spitzer/IRAC frames at 3.6 and 4.5$\,\mu m$. Our co-added images go >2.3 mag deeper than single-epoch frames, cover 50 brown dwarfs, 15 of which have M9 or later spectral types. Spectral types >M9 correspond to masses giant planet domain, i.e., near below Deuterium-burning limit 0.015 Msol. Five 12 PMOs show definitive evidence excess, implying disk fraction 42%, albeit with large statistical uncertainty given small sample. Comparing measurements higher-mass objects, does not decline substantially decreasing mass sub-stellar consistent previous findings. Thus, free-floating potential form their own miniature planetary systems. note that only one six lowest-mass NGC1333, type L0 later, has confirmed disk. Reviewing literature, we find lowest firm detections ~0.01 Msol (or ~10 MJup). It is clear yet whether even lower harbor disks. If not, it may indicate MJup like stars. detection experiment deep Spitzer paves way studies JWST longer wavelengths higher sensitivity, will further explore prevalence formation PMOs.