Talk:Astrophysical jet

Anon rewrite

On 13 March 2006, this article was massively expanded by 81.76.3.42 (talk · contribs). The expanded version can be viewed via this link. I'm concerned about several aspects of it:

• The narrative tone is completely inappropriate. It reads like an essay or press release, not an encyclopedia article, and fixing this would require another massive rewrite.
• All of this material was added over about 15 minutes. Many paragraphs also look like they've been cut off at the end. This suggests that the material might have been cut-and-pasted from somewhere. The fact that nothing in the added material is wiki-linked would be consistent with cut-and-pasting, or could just be the result of inexperience.
• Many of the conjectures put forward are questionable. Most notable is the speculation that Nemesis, a hypothetical companion star to the Sun, was formed as a result of a polar jet emitted during the Sun's formation.

There's probably quite a bit of material worth folding back in, but it will take a lot of effort to properly source it and present it in an appropriate manner. --Christopher Thomas 08:49, 22 March 2006 (UTC)

Atmospheric Science

• 'Polar Jet' is also a term used in atmospheric science, perhaps a link or disambiguation text can be added? 74.60.11.18 (talk) 08:26, 5 July 2008 (UTC)

Merge

• Oppose merge I don't think it should be merged, the polar jets in Herbig Haro objects are not relativistic. --Keflavich 00:38, 18 April 2006 (UTC)
• Oppose merge - they're not the same thing at all. Worldtraveller 18:52, 18 April 2006 (UTC)

Expansion

The most obvious question left unanswered about polar jets is, what causes them? -- Beland 00:49, 21 April 2007 (UTC)

Jet origin inside the black hole

the current article reads: "whereas if it originates in the black hole it will likely be electron-positron in nature". This is confusing because jets can obviously only form on the 'outside' of the event horizon. 86.177.223.152 (talk) 22:07, 2 August 2011 (UTC)

Changed "in" to "from". This should partially address your concern. — Preceding unsigned comment added by 108.46.201.49 (talk) 23:33, 4 February 2016 (UTC)

Title

This article needs a lot of work, but let's start at the beginning. Why on Earth is it called 'polar jet'? Google 'polar jet' and you will see one article in the first few pages using the term in an astrophysical context -- this one. All the rest are meteorological. Nobody in the community calls them 'polar jets'. 'astrophysical jet' would be a lot better if you want a catch-all term; at least that's actually used outside of Wikipedia. Anyone objecting to a rename, please say so.

Mhardcastle (talk) 08:07, 4 March 2014 (UTC)

The article 'Relativistic jet' was merged with this one in August 2012. The mergerer Silent Key proposed it on the Talk:Relativistic jet, got no response, and merged it over the older objections registered above on this talk page. 'Astrophysical jet' would be a much better name for the article. At some point the relativistic version should have its own page again, since it also commonly used in the astronomical literature. StarryGrandma (talk) 01:24, 11 April 2014 (UTC)

OK, as the only comment was in favour, I've renamed the page. Mhardcastle (talk) 19:19, 20 April 2014 (UTC)

Relativistic

I found myself reading this page because of an interest in gamma ray bursts. I don't have any trouble understanding anything in the article except the use of the term "relativistic." I followed up a number of links seeking the answer on Wikipedia, but kept ending up on the page Special Relativity, which didn't help me understand the particular use that was being made of "relativistic." I finally sought enlightenment in the OED and found this lucid definition:

Of an object or a phenomenon: such that differences between the predictions of the theory of relativity and those of Newtonian mechanics or classical electromagnetism are significant, typically because of a speed close to that of light or a strong gravitational field; requiring the theory of relativity for an accurate description.

That made everything instantly clear to me. This definition, or something like it, needs to appear early in the discussion of relativistic jets if it is to make any sense to the nonspecialist.

I am not a scientist, so I would be extremely hesitant to make any changes in such a page. (I do however have a PhD in another field; if a Wikipedia page is incomprehensible to me, it's going to be widely useless.) I'm hoping that someone with the appropriate qualifications will take this on.

Thanks. 03:10, 29 August 2015 (UTC) KC 03:10, 29 August 2015 (UTC) — Preceding unsigned comment added by Boydstra (talk • contribs)

Some changes made to the lede and the body text along the lines of the suggestion above. Mhardcastle (talk) 16:35, 30 August 2015 (UTC)

Both relativistic and ultra-relativistic should be defined. There's a huge Lorentz factor difference between 0.1c and 0.9c ..... I think 0.886c is a Lorentz factor of 2.0 ....... So suggested starting points for this definition: (1) Relativistic velocity defined as > 0.1c ..... and (2) Ultra-relativistic velocity defined as > 0.866c or 0.9c. ....?..108.46.17.166 (talk) 18:31, 31 January 2016 (UTC)BG

More information on the chemical composition of ultra relativistic jets?

This is probably taking liberties but since this is identified as an unsolved problem in physics its probably worth raising some issues here to improve this carefully written article. Probably more information is needed about the chemical composition observations of jets with velocities arbitrarily >0.8c.

If a jet has a velocity >0.8c it should(?) be mostly composed of very tiny particles like electrons, positrons, neutrinos, maybe quarks, other leptons, etc. If full size atoms exist in quantity in an ultra relativistic jet (whew!).... but if full size atoms are present in a >0.8c jet they are probably small in quantity and just going along for the ride. Jets are a source of some cosmic rays? IMHO possibly revealing answers would be had from more chemical composition observations of >0.8C jets from neutron stars, which according to conventional explanations should not have jets roughly >0.5c. Also if >0.8c jets are not mostly composed of the same material as the accretion, what is the reaction and where is the reaction taking place, outside or inside the star? Also if neutron star jets and stellar black hole jets do not always occur simultaneously with accretion it’s a red flag. See these 2 links: http://www.slate.com/blogs/bad_astronomy/2014/02/19/neutron_star_jet_an_exploded_star_creates_a_truly_bizzare_scene.html https://translate.google.com/translate?hl=en&sl=pl&u=https://pl.wikipedia.org/wiki/IGR_J11014-6103&prev=search

According to conventional understanding the jet mechanism is supposed to originate from accretion. How can this neutron star be accreting? It has no binary companion. Was an accreting cloud dragged along with it for 15,000 years? Has this runaway star had this 0.8c jet since it was formed 15,000 years ago? There is some material the neutron star is dragging along but it could very well be side ejecta from the jet or from the star's "boiling" atmosphere. Accretion? Is the glow around the star from accretion radiation or from the star's hot surface or from the jet heating material? In other neutron stars, jet heating of the accretion disk could explain why the Eddington limit is sometimes exceeded. One logical scenario is the 0.8c jet originated within the neutron star all this time, which has interesting implications. There’s an unclear theory about “rotation powered” jets that doesn’t make great sense …… is a spinning magnetic field somehow supposed to suck up material from the poles at >0.8c? My personal belief for the jet origin is core neutrons in an overweight neutron star simply collapse to ultra-relativistic plasma (maybe electron-positron, or other type plasma) which ejects from the magnetic pole and/or rotation axis. This star probably was an almost-black hole that due to an off-center explosion became instead an overweight runaway neutron star. There are 15 known Accreting Millisecond X-Ray Pulsars (AMXPs), and IGR J11014-6103 is not among them.

The pulsar's speed is reported between 0.001 - 0.003c. ..... That seems rather imprecise.

"One of the biggest mysteries is that we only see these jets in x-rays, there's no radio signature.": http://www.abc.net.au/science/articles/2014/02/19/3948039.htm Intense radio emissions from typical neutron stars are likely caused by a jet from the surface blasting thru accretion material. IGR_J11014-6103 apparently has no accretion material and hence no intense radio emissions.

Numbers in the paragraph IGR J11014-6103 are tentative and need better sourcing, should be updated eventually. There should be a project or club for IGR J11014-6103. 173.56.18.42 (talk) 23:32, 6 February 2016 (UTC)BG

More pieces of the puzzle and possible links

Here are two more possible pieces of the puzzle. One is about compact stars possibly creating a large positron-electron cloud, and the other is about a transitional pulsar neutron star jet > 0.8c: http://www.nasa.gov/centers/goddard/news/topstory/2007/antimatter_binary.html http://www.dailygalaxy.com/my_weblog/2015/08/neutron-star-jets-near-speed-of-light-rival-those-of-black-holes.html Picture is artist rendition. 108.46.17.166 (talk) 23:16, 31 January 2016 (UTC)BG

What are the consequences (for the star) of: "reportedly the jet is only seen in x-rays and there is no radio signature[11], possibly due to absence of accretion material." Could the glow be almost all from a small area? Maybe the glow is mostly from the base of the jet. Likely the glow from the neutron star surface (it would be nice to know the surface temperature) is small compared to the base of the jet.

How much energy is emitted by IGR J11014-6103 each year? Is the power level known? ..... At the measured energy loss rate, what is the ratio of (mass-energy ejected)/(neutron star mass) that the star ejects each year? Today its probably a very small ratio. That could provide an estimate of the jet's future age. Has this jet existed for 15,000 years? Maybe initially it was stronger.

Soon there should be images of a super-nova (prior to explosion) which results in the creation of a black hole or neutron star. Neutron stars are preferably created in this process(?). Thats good because maybe a neutron star is more likely to be a runaway and give good images. Regardless if its a neutron star or black hole it will be good to know how soon after the explosion a jet forms, if a jet forms. — Preceding unsigned comment added by 173.56.18.42 (talk) 16:08, 7 February 2016 (UTC)

IGR J11014-6103 is too long for a name. Any suggestions for a shorter name?

IGR J11014-6103 is apparently a radio quite neutron star. See the wiki article: Radio-quiet neutron star These quiet stars are either runaway or an accretion disk disappeared or old! Changing brightness and temperature?

Note on IGR J11014-6103 relativistic jet

The article should have some statements about the history of IGR J11014-6103. Probably its had this jet and no accretion disk since it was ejected from the supernova 10,000+ years ago. Some source should be willing to suggest something. WHERE does the jet material come from? There’s an unclear theory about “rotation powered” jets that doesn’t make great sense ……is somehow a spinning magnetic field supposed to suck up material from the neutron star's poles and eject it at >0.8c?

My opinion: The relativistic jet from IGR J11014-6103 does not originate from an accretion disk and there hasn't been an accretion disk for 10,000 years. This jet originates from within the star, almost certainly from a core with a partially relativistic center. 173.68.155.15 (talk) 18:32, 10 February 2016 (UTC)BG

After the "Rotating black hole as energy source" section there should be a new section for theories about neutron star jets, focusing on jets near c.173.68.155.15 (talk) 01:58, 22 February 2016 (UTC)BG

Update: Added more theories and explanations, but prior to "Rotating black hole as energy source". Interesting that an electron or positron with a Lorentz factor of about 900 (450 MeV/0.5 MeV) can easily escape a neutron star core or even a theoretical 1.10 Schwarzschild radius star and still have most of its energy. Any trace nuclei swept up in this beam would achieve astounding energy. The energy of a swept up nucleus would be (nucleus mass/electron mass) X 450-MeV. Also, an internal jet heating accretion material might explain both some intense radio emission and how the Eddington limit is sometimes exceeded. 68.132.253.173 (talk) 15:00, 23 March 2016 (UTC)BG

Spin value for J11014-6103 ? And mass?

Is the spin rate estimated? A good source for this star is: http://www.aanda.org/articles/aa/pdf/2014/02/aa22588-13.pdf

On page 7 there is mention of spin: "which provides Pspin of the order of 0.1 s"

Does this mean the spin is only 0.1 seconds (6 RPM)? I'm hesitant to publish such a low value. 68.132.253.173 (talk) 14:26, 25 March 2016 (UTC)BG

This PSR has been oriented about the same way for at least 45 years (and probably a lot longer). Thats pretty stable. Very interesting the low RPM. This star could just be shedding excess weight via the jet and the jet is slowly dying. Maybe its mass was/is a little more than 2.0 solar masses. It would be good to have a mass estimate. Maybe its mass can be figured out some way. — Preceding unsigned comment added by 68.132.253.173 (talk) 16:03, 25 March 2016 (UTC)

See this Utube video of anti-matter production in Sagittarius

It indicates Sagittarius produces 15 billion tons/sec of electron-positron matter ?

https://www.youtube.com/watch?v=Sw-og52UUVg