Your post hits on the key words. Gravity and drag.
I dont mean to get all geeky, but there is a fundamental question that I dont see addressed here. Correct me if I missed it. But for the planet to spiral in, one of two things has to happen:
A) the suns gravity has to increase, which means more mass has to come from somewhere (i dont know how that occurs), or
B) the planet has to encounter drag in its orbit, and a lot of it for a spiral to occur. This implies an atmosphere in space, which is normally a vacuum. Without drag, the planets orbit has no reason to decay.
I am not saying this is a non-believable report, but I am skeptical without some theory explaining it. Are they saying that space around this gas giant is as dense as an atmosphere? If so, it would be a 1 in 1 trillion chance that we just happen to be looking at this 1 in a billion stars at this exact moment in time to see this event.
“ This implies an atmosphere in space, which is normally a vacuum..”
Not near a star it isn’t. Charged particles and solar mass ejections would provide drag.
L
This death spiral may have taken a billion years..............
Exactly my earlier observation. The galaxy is big, with lots of opportunity for variation in stochastic events. But how the hell did they stumble on this one far enough in advance to detect the decay in that orbit to document this event?
It blew me away.