Periodic photometric variability in the Becklin-Neugebauer object

The Becklin-Neugebauer object (BN) in the Orion Nebula cluster is a well-studied, optically invisible, infrared-bright young stellar object that is thought to be an intermediate-mass protostar. We report here that BN exhibited nearly sinusoidal periodic variability at the near-infrared H and K-s bands during a 1 month observing campaign in 2000 March/April. The period was 8.28 days, and the peak-to-peak amplitude was similar to0.2 mag. Plausible mechanisms for producing the observed variability characteristics are explored.