Bands of brothers: detecting banded structures in the atmospheres of Luhman 16A and B

To date three brown dwarfs in the L/T transition show signs of planetary-wave light-curve beating. Here, the differential rotation of wave-derived structure in various latitudinal bands causes their individual light curves alternately to constructively and destructively interfere. Luhman 16AB is an intriguing target, with both components exhibiting peculiar behaviors that hint to the existence of bands in their atmospheres. Recently, indirect evidence for bands on Luhman 16A were found using polarization. However, no data exists to date that is able to verify the existence of bands on 16A or B. We propose to observe Luhman 16AB with WFC3 to test the existence of bands in these two L/T transition brown dwarfs. Our observations will 1) test the hypothesis that there are planetary-scale waves and bands in L/T transition atmospheres, 2) verify the ability of polarization to detect bands in exoatmospheres, and 3) nearly double the sample of long-temporal-baseline observations available to detect planetary-scale waves in L/T transition brown dwarfs.