Asymmetries and Outflows in the Circumstellar Dust of Mira A

Asymmetries and motions in the dust shell surrounding Mira A (o Ceti) are reported. Measurements were taken with the UCBerkeley Infrared Spatial Interferometer (ISI), a three-element interferometer operating at 11.15 m. At the time of these observations, it was in a linear, east-west configuration with a maximum baseline of 12 m and thus had a resolution of better than 100mas. Three years of data (2003–2005) are presented and permit observation of the movement of dust shells over time. Fits are made to the visibility and closure-phase curves, which are then used to create one-dimensional profiles of the dust shells. Asymmetries in the circumstellar dust have been observed, and several possible explanations for these asymmetries are explored. Subject headingg s: binaries: symbiotic — infrared: stars — stars: individual (Mira AB) — stars: late-type — techniques: interferometric Online material: mpeg animation