It seems to line up well enough. And it is hard to imagine another explanation.
The gas arrived here 2.5 million years ago. According to https://en.wikipedia.org/wiki/Local_Bubble it seems that the Local Bubble was created 10-20 million years ago by a supernova, and we've been traveling through an area currently occupied it for the last 5-10 million years.
If we've been traveling through that region for 5 million years, and the bubble is expanding as fast as we are moving (and we are moving at a pretty good clip), then we would have encountered the edge of the bubble 2.5 million years ago. Which would be exactly right for that to be this.
And it is hard to imagine that there has been another supernova near us that it could have been, without it having left obvious signs of its existence. So Occam's razor says that this has to be right. The supernova that we know from astronomy had to happen near where we are now is the one that dumped detectable amounts of material on us 2.5 million years ago.
The gas arrived here 2.5 million years ago. According to https://en.wikipedia.org/wiki/Local_Bubble it seems that the Local Bubble was created 10-20 million years ago by a supernova, and we've been traveling through an area currently occupied it for the last 5-10 million years.
If we've been traveling through that region for 5 million years, and the bubble is expanding as fast as we are moving (and we are moving at a pretty good clip), then we would have encountered the edge of the bubble 2.5 million years ago. Which would be exactly right for that to be this.
And it is hard to imagine that there has been another supernova near us that it could have been, without it having left obvious signs of its existence. So Occam's razor says that this has to be right. The supernova that we know from astronomy had to happen near where we are now is the one that dumped detectable amounts of material on us 2.5 million years ago.