Red nova

A "red nova" due to two stars merging might take place in 2022, and would likely be visible from Earth. (Alas, the linked article illustrates this with a picture of two merging bluish stars.)

The stars have been observed orbiting each other with an exponentially increasing angular velocity over the last three years, and they are believed to already be surrounded by a shared envelope of gas. If they are seen merging, this will be the first case of such an event being predicted in advance, making it possible to study the pre-collision phase.

Thanks to +Peter da Silva

The full paper is here:
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