supernova remnant versus planetary nebula

[arecibo (Miguel)]

Thank you Robert & Steven.

I've been too involved with academic hassle (as every first half of any week) to return to this issue.

It's very gratifying to read how, many scrap knowledge I had on the subject, is put together by your contribution.

I've done little progress meanwhile. My first setback was discovering that the Encyclopaedia is out of print

I was reluctant to resort to the Astrophysics Department in my University, but I'm reconsidering it. And, of course, I should raid the Library, just in case.

Anyways, please, keep contributing as you are doing.

PS: I'm starting to read Jacob's paper; it seems to answer half of my question: the distribution of the visible emission lines in PN. As I'm prone to jumping to conclusions (it's builtin, I can't avoid it, lol), please take it with as many grains of salt as convenient.

[madbadgalaxyman (Robert)]

Originally Posted by arecibo

Thank you Robert & Steven.

I've done little progress meanwhile. My first setback was discovering that the Encyclopaedia is out of print

PS: I'm starting to read Jacob's paper; it seems to answer half of my question: the distribution of the visible emission lines in PN.

Hello Miguel,

Yes, the Maran encyclopedia is out of print, but there are still plenty of secondhand copies of it, available for purchase on the internet.
Try one of the "book price comparison engines", and put in the ISBN of the encyclopedia into the search box:
www.abebooks.com
www.bookfinder.com
www.bookfinder4u.com
www.fetchbook.info
- also, can try the secondhand network of amazon.com

I agree, Jacob does address the issue of the distribution of emission lines in a planetary nebula. But, the situation within a SNR must be a lot more complex than in a planetary nebula, due to the existence of multiple shockwaves within the object.
(I seem to recall that planetary nebulae expand at a relatively low velocity of about 20-50 km/s)

cheers, Mad Galaxy Man

[Merlin66 (Ken)]

You should also have a look at Gaposchkin's "The Galactic Novae"
Chapter 10: "Comparative study of Spectral Development" gives a good insight into the subject.

Also James Kaler's "Stars and their Spectra" discusses both SN and Planetary spectra, with example spectra.

[madbadgalaxyman (Robert)]

Originally Posted by Merlin66

Also James Kaler's "Stars and their Spectra" discusses both SN and Planetary spectra, with example spectra.

Kaler's book is excellent.

"Stars and Their Spectra" by James Kaler is one of the clearest and most cogent "popular-level" introductions to stellar evolution, stellar spectra, the OBAFGKM sequence, and the Hertzprung-Russell Diagram(= color-magnitude diagram). The second edition was published in 2011.

It is quite remarkable how Kaler manages to effortlessly convey a detailed understanding of stellar evolution and stellar spectra, without muddy explanations and without unnecessary complexities and complications.

He takes the relatively easy approach of explaining and linking together the observables such as stellar spectra, stellar luminosity, stellar color, and stellar spectral type, instead of "getting really heavy" with a detailed discussion of the internal constitution of the stars.

I note that one of the reviewers at amazon.com says that the spectra are very poorly reproduced in the second edition. (I have the very nicely produced First Edition). One of the most important features of the book is the spectra, so this would be a major flaw.
____________________

Ken, is that Payne-Gaposchkin's book written in the early 1960s?
She was a very very good writer of astronomy books, but the date of publication would indicate that some caution is in order;
humankind's knowledge of planetary nebulae was only in its infancy in the 1960s.
Because much of the basic information about planetaries was obtained between 1960 and 1980, I would be a little cautious about the book's conclusions as to what is going on in these nebulae.
_______________________

[Merlin66 (Ken)]

Robert,
I have both the 1st and the 2nd Editions in hardcover and the printing of the spectra is 100% OK.
I did have a paperback copy of the 1st edition where the reproduction of the spectra (and illustrations in general) was very poor.

[arecibo (Miguel)]

Hi, all.

Good to see that my rather naïve question gave birth to a brain storm of far from naïve contributions.

I'm interested in almost everything Astrophysical, so you've given me enough food for thought for month or years to come.

I would like to summarize what I've learned in this thread: My question (I realize now) was one about morphology (and the underlying Physics, of course). Or, rather, two questions about morphology, with a third implicit.

When you see images of nebulae, you notice three kind of shapes:

Highly regular, in many planetary nebulae.

Highly irregular, like in M42, M78, IC1318, IC5146, NGC7000, The Cone Nebula region, M8, M20, etc (I mention ones that I've imaged or seen at a telescope).

And mildly regular, in supernova remnants (I've seen less of these).

So it was an easy jump (not really well founded) to associate shape with physical origin. I know that (bright) irregular nebulae are of two kinds (emission and/or reflection), and that some ENe and RNe can be rather regular in shape (The Rosette Nebula, for example).

Ok. So, the shape of PNe is more or less explained to (my) satisfaction. The "less" part is to account for new developments (and variations on the nebula formation process and "final" shape, not because I'm not satisfied). The general shape of emission and reflection nebulae does not need a general explanation.

And my observations of SN was too limited for allowing a general conclussion about their shapes.

Let's say that my quest is fulfilled. However, I'll read "con gusto" more contributions to the theme.

[Weltevreden SA (Dana)]

We shouldn't overlook (pardon the pun) the role of magnetohydrodynamics (MHD) in PN and SN remnant formation. Filaments and threads are magnetic sheets that we can see, and MHD turbulence plays a major role in stellar evolution, from coalescing molecular clouds to final dispersion into the intergalactic medium. Without magnetic forces our sun would be a hot but very boring object. There are so many papers on how MHD affects both PN shapes and SN remnant dispersion that one can get a bit addlepated trying to keep up with it all. Google Scholar lists the following references for MHD in PNs:

http://scholar.google.co.za/scholar?...1%2C5&as_sdtp=

amid which this paper is a good starter kit:

http://www.annualreviews.org/doi/abs...rnalCode=astro

For MHD in SNrs:

http://scholar.google.co.za/scholar?...1%2C5&as_sdtp=

arXiv weighs in as well, though less voluminously:

http://arxiv.org/find/all/1/all:+AND.../0/1/0/all/0/1

http://arxiv.org/find/all/1/all:+AND.../0/1/0/all/0/1

Most of this stuff is a lot chewier than the books Robert recommends. The turgid prose of professional papers is redeemed by their up-to-the-minute data, but they sure are a handful to read.

[Weltevreden SA (Dana)]

Hardly had I sent off my earlier message than I came across this brand-new paper (6 days old, publ. 22 Feb 13) on arXiv that lucidly explains all the basic terms and ideas in galactic MHD. The lead author is Rainer Beck, a familiar name on enthusiast forums. For a startling visual analog to a late-stage SNr only on a grand scale, check out the polarization map of the MW on p.13.

[madbadgalaxyman (Robert)]

Originally Posted by Weltevreden SA

We shouldn't overlook (pardon the pun) the role of magnetohydrodynamics (MHD) in PN and SN remnant formation. Filaments and threads are magnetic sheets that we can see, and MHD turbulence plays a major role in stellar evolution, from coalescing molecular clouds to final dispersion into the intergalactic medium. Without magnetic forces our sun would be a hot but very boring object. There are so many papers on how MHD affects both PN shapes and SN remnant dispersion that one can get a bit addlepated trying to keep up with it all. Google Scholar lists the following references for MHD in PNs:

Very interesting comment, Dana. You are quite obviously someone who loves astrophysics.

I hope that I am going to have the time to read the papers you mention!

I have read some of Beck's papers on the magnetic fields within galaxies, and I have managed to understand some current ideas about the effects of magnetic fields in the formation of protostars and stars.
On the whole, I do look at things from the "galaxies" point of view:
I mainly read papers on the morphology and classification of galaxies, the kinematics/dynamics of galaxies and their constituents, on AGNs, plus the necessary papers on Star Formation and the ISM and Supernovae (for the purpose of enhancing my understanding of galaxies. )

I do wish that I knew more astrophysics so as to better interpret astronomical data, as I am more of the practical astronomer, with a love of good data and observations, such as: mass & luminosity functions of various objects, galaxy magnitudes, spectral line emission, photometric systems, distance measurement techniques, the space distribution & the peculiar velocity field of galaxies, etc.
However, as the career of Fritz Zwicky conclusively proved , you can discover an awful lot of things in astronomy without knowing every part of the physics; he had great physical insight, and an enormously creative ability to come up with new and physically plausible ideas, plus he was so extremely arrogant that he didn't at all care if everybody else thought that one of his ideas was very wrong. )

cheers, Robert

[Weltevreden SA (Dana)]

Thanks to you, too, Robert. I didn’t know anything about the GALEX discoveries of hot gas cloud formation in galactic exurbs till I read your info in the SN 2013aa / NGC 5643 thread. Interestingly, the XMM-Newton time allocators haven’t ventured into intergalactic gas properties the way the GALEX team has.

The Carnegie-Irvine Galaxy Survey image of 5643 and other images you ferreted out were very informative, and likewise news to me. The same goes for the Lauberts and Valentijn Catalog (ESO-LV). I’ve been relying on WikiSky and RC3, neither of which give the depth of motion and spectral data that ESO and NED provides. I looked at Project Pluto at your behest. At present I’m been using AstroPlanner. I must decide whether Pluto’s data fits my needs better.

Interesting that you mentioned Fritz Zwicky. Before PhD programs were formalized in their current form, everyone was self-taught. E E Barnard was self-taught and made immense contributions to our understanding. I haven’t the time to look into self-trained astronomers of contemporary times, but the world of geology has, if anything, even more home-brew geniuses than astronomy. To say nothing of Linneus the botanist.

I really look forward to your comments in these and future topics. Learning something new every day is as good for mental health as an apple a day is for body health.