title: Water Vapor Maser "Turn-On" in the HII Region W3 (OH).
abstract: A line in the water vapor maser spectrum of the HII region W3(OH) was observed to increase in brightness over an 8-day period and then decline to its original intensity over the following 4 weeks. The intensity variation can be explained by a simple maser model, with an impulse of energy suddenly applied. The observed time scale and energy output are consistent with a maser on the outskirts of a dust cocoon surrounding an O5 star, with a momentary "leak," lasting a day or. two, supplying the necessary energy.
authors.forename: A D
authors.initials: AD
authors.lastname: Haschick
authors.forename: B F
authors.initials: BF
authors.lastname: Burke
authors.forename: J H
authors.initials: JH
authors.lastname: Spencer