出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：o Ceti is known as the prototype of the Mira stars and yet it is a highly atypical object. It was first detected in the OH ground state at 1665 MHz in 1975, but stopped emitting for about 15 years. In the 1990’s, it underwent an OH eruptive event leading to long lasting 1665 MHz emission and also to intermittent 1667 MHz emission in mid-1992, and finally faded away in early 1999. After another 10 years of non-emissivity, in November 2009 we detected with the Nançay Radio Telescope (NRT) a new outburst in the OH 1665 MHz line towards Mira Ceti. This prompted us to start frequent monitoring of this source with the NRT, and to apply for a EVN-MERLIN ToO which led to a successful phase-referenced observation in February 2010. The superb angular resolution achieved with the EVN in February 2010 allowed us to locate the maser at 200 mas (∼26 AU) east of o Ceti.
