Breathtaking image of a red giant star swallowing another star

Astronomers captured this incredible image of a double-star system where a red giant star appears to have "engulfed the other (star) which, in turn, spiraled towards its partner provoking it into shedding its outer layers." The scientists spotted this astounding event using the Atacama Large Millimeter/submillimeter Array (ALMA) radio telescope in the Chilean Andes. From the European Southern Observatory's (ESO) announcement:

Thanks to new observations with ALMA, complemented by data from the ESO-operated Atacama Pathfinder EXperiment (APEX), Olofsson and his team now know that what happened in the double-star system HD101584 was akin to a stellar fight. As the main star puffed up into a red giant, it grew large enough to swallow its lower-mass partner. In response, the smaller star spiralled in towards the giant’s core but didn’t collide with it. Rather, this manoeuvre triggered the larger star into an outburst, leaving its gas layers dramatically scattered and its core exposed.

The team says the complex structure of the gas in the HD101584 nebula is due to the smaller star’s spiralling towards the red giant, as well as to the jets of gas that formed in this process. As a deadly blow to the already defeated gas layers, these jets blasted through the previously ejected material, forming the rings of gas and the bright bluish and reddish blobs seen in the nebula.

A silver lining of a stellar fight is that it helps astronomers to better understand the final evolution of stars like the Sun.

Here's the scientific paper: HD 101584: circumstellar characteristics and evolutionary status (Astronomy Astrophysics)