THE PROPERTIES OF THE 500 K DWARF UGPS J072227.51–054031.2 AND A STUDY OF THE FAR-RED FLUX OF COLD BROWN DWARFS S. K. Leggett, D. Saumon, M. S. Marley, K. Lodders, J. Canty, P. Lucas, R. L. Smart, C. G. Tinney, D. Homeier, F. Allard, Ben B…