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#11
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Eureka! The Proverbial Smoking Gun
In article , "Robert L.
Oldershaw" writes: [Mod. note: this paper suggests that the X-ray emission comes from the corona of the star or from star-disc interactions; they certainly do not say it is a 'point source at the center of the star' -- which is of course impossible -- or that it is associated with the jets. -- mjh] It is true that I "jumped the shark" a bit on my characterization of the X-ray data. That should probably be "jumped the gun" (a metaphor arising from track and field sports where one should not start before the starting gun is fired). "Jump the shark" refers to an episode of 1970s sitcom "Happy Days" (which was set in the 1950s) where the Fonz character did indeed jump a shark while waterskiing. It has since come to refer to an event which is so lame that it is clear to all that there is no hope left (usually within the context of television serials). Well, maybe you did jump the shark here. :-) [Mod. note: I've allowed this because it's informative and amusing, but let's try to stay on topic -- mjh.] |
#12
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Eureka! The Proverbial Smoking Gun
On Dec 19, 8:15*am, Phillip Helbig---undress to reply
wrote: In article , "Robert L. Solar models are so detailed and so well checked that, after the experiments were deemed good enough, people decided on "new physics" (hence confirmed: neutrino oscillations, implying that neutrinos have mass) rather than doubt the models. But can these "so detailed" and "so well checked" models explain how the Sun gets its magnetic field, and can these models tell us what is going on with the Sun's enigmatic 22-year solar magnetic cycle, in which the global dipole field and the sunspots flip polarity roughly every 11 years?! Only with many untested assumptions and a whole lot of mathematical hand-waving can the theorists come up with something halfway plausible. No one regards these problems as solved with present models. In astrophysics, many things can be explained; many things cannot be explained. We would do well to keep an open mind regarding the extent of our knowledge, and the lack thereof. Most importantly, let us not pre-judge the outcome of the definitive prediction before the testing is done. I say the jets of PB Piscium will be traced to within 10 km of its geometric center. Conventional astrophysics says that is completely impossible. Perfect! Now let us allow NATURE to say who is right. [Mod. note: how exactly do you propose to 'test' this proposition? -- mjh] RLO www.amherst.edu/~rloldershaw |
#13
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Eureka! The Proverbial Smoking Gun
[Mod. note: how exactly do you propose to 'test' this proposition? -- mjh] In qualitative terms, exactly the same way as the jets in the giant elliptical galaxy M87 were gradually traced to the very center of the galaxy. [Mod. note: M87 is transparent to photons at a wide range of wavelengths. A star is not -- mjh] And exaxctly the same way that "totally unobservable" atoms can now be, at least indirectly, observed. To be perfectly honest I have no idea what methods that are currently well-known and/or those that are currently unknown will be required to test this prediction. However, I have very little doubt that the definitive prediction will be tested. Hopefully direct tests will be possible, but if not, then at least indirect testing will be posible. Perhaps very sophisticated stellar seismology will be required to be developed and then utilized in the case of BP Piscium. Perhaps clever research scientists will figure out a way to test this prediction using methods we know about but have never considered applying in this type of context. Bottom line: The deep internal structure of stars is far too important a research area to remain largely unexplored. If there is a will, then a way will be found. RLO www.amherst.edu/~rloldershaw |
#14
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Another Very Promising Test System
Quick Version: The central regions of some "coreless" planetary
nebulae should contain Kerr-Newman ultracompact objects and/or neutron stars. Longer Version: Planetary nebulae offer a good class of test systems for testing the definitive prediction that all stellar objects have K- NU nuclear objects at their centers. In these systems the star has ejected one or more plasma envelopes, which have such beautiful and highly suggestive morphologies (a comparison with the morphologies of the electronic wavefunctions of atoms is quite remarkable). Note that the energies involved in PNs are are roughly 6 orders of magnitude lower than the energies of supernova. Therefore, according to conventional astrophysics, K-NU nuclei and neutron stars are 'not supposed to form' in PN events. In some cases a low-mass star could conceivably eject all of its plasma envelopes and the only thing remaining at the center would be one of the hypothesized K-NUs or neutron stars. It would not be a trivial matter to identify such an object at the center of a PN because the PN are very large and many candidate central sources would have to be asessed and ruled out. However, this test is definitely feasible now with existing technology. Some relevant information: (1) A significant fraction of PN do not have confidently identified central objects. Some are referred to as "coreless". These would be good target systems. (2) The lower the mass of the original star, the higher the probability of an event that removes everything but he hypothesized K- NU nucleus. (3) The recently (2008?) discovered undesignated "Cygnus Bubble" PN, which is very faint and almost perfectly spherical, is a very interesting test system. After detective work by astronomers, a very blue stellar object was detected at geometric center. Isolated neutron stars also have been found to be blue in color when they have been imaged. Obviously, this central object needs to be looked at very carefully, but I have not yet found a really thorough scientific study of it. (4) The hyothesized K-NU nuclei would be expected to be potential emitters of Gamma-rays, X-rays and radio waves, depending on their state of excitation and mode of de-excitation. Therefore the Chandra and Fermi data might provide very useful identification and diagnostic information. (5) If one neutron star turned up near the center of a "coreless" PN, one could not infer too much about it. But if many ultracompact objects were found at the centers of "coreless" PN, then random chance could rapidly be ruled out. Happy Solstice, RLO www.amherst.edu/~rloldershaw |
#15
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Stellar Magnetic Fields
At this point I would like to refine the R and B estimates used to
arrive at the 1/R^2 scaling for the global dipole B fields of "magnetic" subclasses of several major classes of stars. The equation under consideration is: B = B* / (R/R*)^2 , where the * designates the average values of B and R for neutron stars. In log form the equation is: log B = 13.25 - 2 log R/R* For neutron stars: log R* = 6.0 and log B* = 13.25 For white dwarf stars: log R = 9.0 and log B = 6.0 For M dwarfs: log R = 10.3 and log B = 3.5 For beta Cepheids: log R = 11.3 and log B = 2.2 For O,B,A,F,G Giant stars: log R = 11.9 and log B = 0 When you plot this up, you get a straight line that is approximated by the log equation given above. If one should doubt that the R and B values I use are appropriate, I would appreciate being directed to empirical data that would suggest other R and B values that might be more appropriate. Happy Holidays, RLO www.amherst.edu/~rloldershaw |
#16
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planetary nebulae and neutron stars
[[Mod. note -- I've taken the liberty of changing the subject line from
" Stellar Magnetic Fields" to "planetary nebulaa and neutron stars", since this article really doesn't have much to do with stellar magnetic fields. -- jt]] If you read "Central Stars of Planetary Nebulae:...catalogue" which can be obtained at this link: http://arxiv.org/PS_cache/arxiv/pdf/...010.5376v1.pdf , then you know that: (1) of roughly 3,000 PNs that are known, the majority of their central stars have not been identified and spectroscopically studied, and (2) of the the central stars that have been studied, a significant percent are classified as "blue" objects. Isolated neutron stars have been observed optically, for example see: http://iopscience.iop.org/1538-4357/..._588_1_L33.pdf and the Nature paper of 1997 by Walter and Matthews. One can also search on Mignani's research on the spectroscopy of neutron stars via arxiv.org. The main point is that the above references note that neutron stars are observed as being very "blue" objects when they can be observed in the optical range. My question, and here I need more than a little help from experienced astrophysicists, is as follows. Could the "blue" objects at the centers of many (some) planetary nebulae be neutron stars? If one compares the spectroscopic (and other) data for the two classes of "blue" objects, might there be a provocative overlap? If there is a significant overlap, then I think we have something to write home about, so to speak. Happy New Year (but I suggest that you drink fine coffee instead of that crankcase oil), RLO www.amherst.edu/~rloldershaw |
#17
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planetary nebulae and neutron stars
In article
, "Robert L. Oldershaw" writes: (1) of roughly 3,000 PNs that are known, the majority of their central stars have not been identified and spectroscopically studied, OK. and (2) of the the central stars that have been studied, a significant percent are classified as "blue" objects. OK. Isolated neutron stars have been observed optically, for example see: http://iopscience.iop.org/1538-4357/..._588_1_L33.pdf and the Nature paper of 1997 by Walter and Matthews. One can also search on Mignani's research on the spectroscopy of neutron stars via arxiv.org. The main point is that the above references note that neutron stars are observed as being very "blue" objects when they can be observed in the optical range. OK. My question, and here I need more than a little help from experienced astrophysicists, is as follows. Could the "blue" objects at the centers of many (some) planetary nebulae be neutron stars? If one compares the spectroscopic (and other) data for the two classes of "blue" objects, might there be a provocative overlap? If there is a significant overlap, then I think we have something to write home about, so to speak. Save your stationery. Most have not been observed. Some have been observed. Neutron stars are blue. It's a big jump to assume that the unobserved ones are neutron stars. Lots of stellar objects are blue. More significantly, those that have been observed are NOT neutron stars. I don't know who owns most of the expensive cars in my town. The few owners I do know are rich. NBA players are rich. Should I assume that most of the expensive cars in my town are owned by NBA players? |
#18
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planetary nebulae and neutron stars
On Jan 3, 11:15 pm, (Phillip Helbig---
undress to reply) wrote: I don't know who owns most of the expensive cars in my town. The few owners I do know are rich. NBA players are rich. Should I assume that most of the expensive cars in my town are owned by NBA players? Be my guest. But these quaint analogies bear no resemblance to my reasoning, thank you. Save your stationery. Most have not been observed. Some have been observed. Neutron stars are blue. It's a big jump to assume that the unobserved ones are neutron stars. Lots of stellar objects are blue. More significantly, those that have been observed are NOT neutron stars. If one has an adequate understanding of the new paradigm I work within, then one knows that I expect the overwhelming majority of PN nuclei to compact high-temperature stars, as is observed in the small fraction of PN nuclei that have been studied carefully. The case wherein all of the original star's shells have been ejected, leaving a bare neutron star-like nucleus, should be far less probable. Perhaps only 1% to 10% of PNN will be of this type. So it is very premature for you to assume that my prediction is ruled out. It most certainly has not been ruled out, if we are deciding by scientific methods. The type of system I am predicting: a planetary nebula with a neutron star-like nucleus will most likely be found at the center of faint spherical PN such as the Soap Bubble Nebula PN G75.5+1.7, which was mentioned earlier in this thread. When we have characterized the PN nuclei of 100 faint systems, and at least 100 of the more typical PN systems, then we will have enough hard data to say with some scientific confidence, rather than bluster or wishful thinking, whether or not there is a definite overlap between the observed properties of isolated neutron stars and some PN nuclei. RLO www.amherst.edu/~rloldershaw PS: If anybody wants to see a graph showing that the B and B-max values for various star classes fit my 1/R^2 conjecture rather well, send me an email and I will attach the graph to the return email. |
#19
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planetary nebulae and neutron stars
In article ,
"Robert L. Oldershaw" writes: (2) of the the central stars that have been studied, a significant percent are classified as "blue" objects. "Blue" isn't quantitative, but all PN central stars should have temperatures above 30000 K. Could the "blue" objects at the centers of many (some) planetary nebulae be neutron stars? Nothing I know rules out a PN central star having a neutron star companion, but I don't see how a neutron star (only a few km in diameter) could produce enough ionizing photons to keep the nebula ionized. Central star temperatures are known from the nebular line ratios, so you can't do it just by cranking up the temperature. This is aside from pretty good stellar evolution theory. -- Help keep our newsgroup healthy; please don't feed the trolls. Steve Willner Phone 617-495-7123 Cambridge, MA 02138 USA |
#20
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planetary nebulae and neutron stars
In article ,
"Robert L. Oldershaw" writes: I am formally proposing that the central nuclei of a subset of PNae will consist of SINGLE objects, and that these nuclei can be approximated by unaccompanied neutron stars. ..... Let's do the observational testing FIRST Perhaps you might have another look at the part about ionizing photons. Where do you think they're coming from, if the central object is something like a neutron star? -- Steve Willner Phone 617-495-7123 Cambridge, MA 02138 USA |
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