A T8.5 brown dwarf member of the ξ ursae majoris system

Edward L. Wright, M. F. Skrutskie, J. Davy Kirkpatrick, Christopher R. Gelino, Roger L. Griffith, Kenneth A. Marsh, Tom Jarrett, M. J. Nelson, H. J. Borish, Gregory MacE, Amanda K. Mainzer, Peter R. Eisenhardt, Ian S. McLean, John J. Tobin, Michael C. Cushing