by Ann » Wed Feb 15, 2017 3:36 pm
Okay, new post, because if the Calabash Nebula is indeed a member of open cluster M46, then we should be able to make a qualified guess as to the progenitor of this proto-planetary. According to
Wikipedia, the estimated age of M46 is about 300 million years. That means that the progenitor of the Calabash ran out of both hydrogen and helium in its core in about 300 million years. What kind of star runs through its main sequence
and its red giant lifetime so quickly?
Wikipedia wrote:
A-type stars are young (typically few hundred million years)
So it was not an A-type star, because it wouldn't have run through the full course of its life in 300 million years. It was a B-type star, therefore. (Not an O-type star, because they don't live for 300 million years, and they go supernova anyway.)
My software, Guide, suggests that there are still stars of late spectral type B in M46. So I'm going to guess that the progenitor star of the Calabash Nebula was a mid-to-late-type spectral type B star, of perhaps, say, spectral typ B7, starting its life with at least three solar masses under its belt, maybe as much as 3.5 or possibly four solar masses.
I repeat what I have said before: Almost all the planetary nebulas and proto-planetary nebulas that we see in the sky had progenitor stars that were (much) more massive than the Sun.
As Yoda would have said: Powerful stars, they were! Planetary nebulae, they are!
Ann
Okay, new post, because if the Calabash Nebula is indeed a member of open cluster M46, then we should be able to make a qualified guess as to the progenitor of this proto-planetary. According to [url=https://en.wikipedia.org/wiki/Messier_46]Wikipedia[/url], the estimated age of M46 is about 300 million years. That means that the progenitor of the Calabash ran out of both hydrogen and helium in its core in about 300 million years. What kind of star runs through its main sequence [i][b]and[/b][/i] its red giant lifetime so quickly?
[quote][url=https://en.wikipedia.org/wiki/A-type_main-sequence_star#Planets]Wikipedia[/url] wrote:
A-type stars are young (typically few hundred million years)[/quote]
So it was not an A-type star, because it wouldn't have run through the full course of its life in 300 million years. It was a B-type star, therefore. (Not an O-type star, because they don't live for 300 million years, and they go supernova anyway.)
[float=left][img2]http://tinyurl.com/z4u6cyg[/img2][c][size=70]Okay... this isn't a B-type star or a planetary nebula, but a pulsar. I just like the picture. Sue me!
Image credit: NASA/JPL-Caltech/SAO, source: https://www.nasa.gov/jpl/nustar/pia18836.[/size][/c][/float]My software, Guide, suggests that there are still stars of late spectral type B in M46. So I'm going to guess that the progenitor star of the Calabash Nebula was a mid-to-late-type spectral type B star, of perhaps, say, spectral typ B7, starting its life with at least three solar masses under its belt, maybe as much as 3.5 or possibly four solar masses.
[float=right][img2]https://pbs.twimg.com/media/CKSAugEWgAAUw0J.jpg[/img2][/float]I repeat what I have said before: Almost all the planetary nebulas and proto-planetary nebulas that we see in the sky had progenitor stars that were (much) more massive than the Sun.
As Yoda would have said: Powerful stars, they were! Planetary nebulae, they are!
Ann