Hinkley, SashaCarpenter, J MKraus, Adam LIreland, Michael2015-12-102041-8205http://hdl.handle.net/1885/66694We report the results of Keck L′-band non-redundant aperture masking of HR 8799, a system with four confirmed planetary mass companions at projected orbital separations of 14-68 AU. We use these observations to place constraints on the presence of planeAuthor/s retain copyrightKeywords: instrumentation: adaptive optics; instrumentation: interferometers; planets and satellites: detection; stars: individual (HR 8799); techniques: high angular resolution201110.1088/2041-8205/730/2/L212016-02-24