Measuring the wind speed on a radio-emitting brown dwarf

We propose for photometric monitoring observations of 2MASS J10475385+2124234 using Spitzer/IRAC. 2MASS J1047+21 is a late spectral type (T6.5) radio emitter with a measured radio period of 1.77 hrs. As a part of our successful Cycle 13 program, we detected photometric variability for 2MASS J1047+21. Our proposed observations will not only characterize this variability of the coolest known radio emitter, but also provide a unique opportunity to measure the wind speed of this brown dwarf. Spitzer is currently the only facility capable of the photometric stability, continuous observations and 4.5 micron sensitivity necessary for the success of our program.