A binary in outburst
In our last issue we looked at how to make a variable star brightness estimate, using the Mira-type variable TT Monocerotis as our example. If you’ve got that issue handy,. I latched on to this star in 2005 because, like a baited hook, the chart I had at the time labelled the variable as ‘type unknown’. V694 Mon is in fact a symbiotic star, an interacting binary system comprising a red giant and white dwarf. In V694 Mon’s case the system has an accretion disc expelling a jet of gas that just happens to be pointed at us along our line of site.
