The 1996-1997 Fading of V651 Monocerotis, the Binary Central Star of the Planetary Nebula NGC 2346
/ Abstract
V651 Mon is the binary central star of the bipolar planetary nebula NGC 2346. The star showed the second-ever deep fading in 1996–1997, which was presumably caused by obscuration by a dust cloud in the planetary nebula, as was proposed to explain the 1981–1985 event. The entire duration of the 1996–1997 event was ∼400d, remarkably shorter than the 1981–1985 event, suggesting that the obscuring body was smaller or had a larger tangential velocity. The most remarkable feature in this event was the presence of a sharply defined transient clearing (brightening). From the time-scale of the variation, we propose an upper limit of the projected scale of several times ∼ 10 11 cm of the structure responsible for the brightening. This observation provides the first evidence for a sharply defined,
Journal: Publications of the Astronomical Society of Japan