by rstevenson » Tue Jan 13, 2015 3:22 pm
Boom, you seem to be saying that a nicely symetrical bubble-like nebula cannot occur as the result of the death throws of a star. But it can. All it requires is that the forces are not thrown out of balance by something else -- a binary companion or close-in hot-Jupiter, for example, either of which could cause the nebula to take on an odd shape. So if this is indeed a planetary nebula resulting from the near-final processes of an old star, its simple shape may just mean that the star had few, small and distant planets -- or none at all, so its gaseous envelope was puffed off without disturbance.
As for whether there is a central star here, the most I could say from just this picture is that I can't see which star is the central star. I wouldn't state, just from that, that there is no central star. (But I would go looking for it, just to be sure.)
Rob
Boom, you seem to be saying that a nicely symetrical bubble-like nebula [i]cannot[/i] occur as the result of the death throws of a star. But it can. All it requires is that the forces are not thrown out of balance by something else -- a binary companion or close-in hot-Jupiter, for example, either of which could cause the nebula to take on an odd shape. So if this is indeed a planetary nebula resulting from the near-final processes of an old star, its simple shape may just mean that the star had few, small and distant planets -- or none at all, so its gaseous envelope was puffed off without disturbance.
As for whether there is a central star here, the most [i]I[/i] could say from just this picture is that I can't see which star is the central star. I wouldn't state, just from that, that there is no central star. (But I would go looking for it, just to be sure.)
Rob