ALMA catches a dying star mid-transformation, with a ring from its last outburst
Stars are stubborn about their endings. Most of them take tens of thousands of years to die, and we usually only catch the before and after. What ALMA just caught is the middle, a star caught mid-shedding with a ring that looks like a snapshot of its last big heave. That ring is a fossil of a specific event, a record of how much material the star threw off and how fast.
I keep thinking about what that means for our own sun. It will do something like this in a few billion years, puffing away its outer layers before settling into a white dwarf. A ring like this one would be the last thing it writes into the sky. There is something quietly moving about that.
I would want to know what kind of star this is and how the ring's shape and speed line up with models of how these outbursts happen. The paper is fresh on arXiv, so the details are still settling. But any time we catch a star in the act of becoming something else, it feels like we are reading a page of the universe's diary.