The Recurrent Eclipse of an Unusual Pre-Main-Sequence Star in IC 348

The recurrence of a previously documented eclipse of a solar-likepre--main-sequence star in the young cluster IC 348 has been observed. Therecurrence interval is 4.7 $\pm 0.1$ yr and portions of 4 cycles have now beenseen. The duration of each eclipse is at least 3.5 years, or $\sim 75$% of acycle, verifying that this is not an eclipse by a stellar companion. The lightcurve is generally symmetric and approximately flat-bottomed. Brightness atmaximum and minimum have been rather stable over the years but the light curveis not perfectly repetitive or smooth and small variations exist at all phases.We confirm that the star is redder when fainter. Models are discussed and it isproposed that this could be a system similar to KH 15D in NGC 2264.Specifically, it may be an eccentric binary in which a portion of the orbit ofone member is currently occulted during some binary phases by a circumbinarydisk. The star deserves sustained observational attention for what it mayreveal about the circumstellar environment of low-mass stars of planet-formingage.Comment: Accepted for publication in ApJ (Letters