SIMBAD references

Photometry and spectroscopy of the unique pre-main-sequence eclipsing object KH 15D in the young cluster NGC 2264 are presented. The orbital period is 48.34 days, and both the length (∼16 days) and depth (∼3 mag) of the eclipse have increased with time. A brightening near the time of central eclipse is confirmed in the recent data but at a much smaller amplitude than was originally seen. Spectra taken when the star is bright show that the primary is a weak T Tauri star of spectral type K7. During eclipse there is no detectable change in spectral type or reddening, indicating that the obscuration is caused by rather large dust grains and/or macroscopic objects. Evidently, the star is eclipsed by an extended feature in its circumstellar disk orbiting with a semimajor axis of ∼0.2 AU. Continued photometric monitoring should allow us to probe the disk structure with a spatial resolution of ∼3x10⁶ km or better.