This is an archive of past discussions about Neutron star. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page.
The classification is introduced in Section 3 of that paper to interpret the model that the authors present. Given that the paper only has 38 citations, I'd say that the classification has not come into widespread use. Best, Wham2001 (talk) 06:47, 20 November 2019 (UTC)
Is there an article error in the escape velocity from neutron stars?
The escape velocity from a neutron star is often stated (as in the article) to be one-third to one-half c. If the heaviest, densist neutron star is 2.0 solar masses with a radius of 12-km, this corresponds to a Schwarzschild ratio of 2.0 .... Using the formula for escape velocity it seems the escape velocity is 0.7c Is this correct? 209.150.58.4 (talk)BG — Preceding undated comment added 02:30, 14 May 2022 (UTC)
Uncertainties in neutron star properties should be better emphasized (and updated)
Many of the estimates of neutron star properties reported in this article don't effectively represent the uncertainties associated with these quantities and are likely confusing to readers. For example the maximum TOV mass is quite uncertain, and I'm not sure where the 2.1 number quoted comes from, the Chamel paper explicitly gives an upper bound of about 3 solar masses, but both this paper and the Özel paper were published years before the mass measurements of J0740+6620, which gives about a 2.1 solar mass lower bound on the TOV mass. The Rezzolla paper (one of several based on multimessenger data from 170817) also has an associated uncertainty, which places a 90% credible region upper bound closer to 2.3 solar masses, which should be quoted in the article. Neither 2.1 or 2.16 are consistent with the 2.35 +- .17 solar mass number from the intro for PSR J0952–0607 at 90% confidence. In general I think the correct approach here is to quote broad ranges for these values where it is necessary, and report estimates from individual papers clearly with uncertainty. In many places it's impossible to tell if ranges quoted refer to theoretical uncertainties or just natural variation in the population of neutron stars such as: "The neutron star's density varies from... to 6×1017 or 8×1017 kg/m3", usually such a statement would explicitly say "a typical 1.4 solar mass neutron star has density such and such". I also have no idea where these numbers come from but they are certainly not from the Lattimer paper, though they may be from Cole Miller's neutron star website which is inexplicably linked to in the reference that's supposed to be Lattimer's intro to neutron stars paper. Even then these numbers don't seem to accurately reflect what the page says, which is that neutron stars will likely have central densities several times nuclear densities (i.e. several times 2.8×1017 kg/m3) a much larger range than is quoted. INLegred (talk) 07:05, 9 February 2023 (UTC)
"Mass Limit"
It is worth noting that mass limit of a neutron star is dependent on star's mass but also spin and make up. https://adsabs.harvard.edu/full/1975BAAS....7..546B - obese neutron star paper written by Harvard scholar. The Tolman–Oppenheimer–Volkoff limit (or TOV limit) is an upper bound to the mass of cold, non-rotating neutron stars, analogous to the Chandrasekhar limit for white dwarf stars. If the mass of a neutron star reaches the limit it will collapse to a denser form, most likely a black hole. This limit for a while was set at 2.1 solar mass, however this estimate was for non-rotating neutron star. However, fast spinning or rotating neutron stars mass could exceed this limit, for obvious reasons. Anyways, just wanted to ad few pointers here when talking about neutron star mass and that not everything is as clear cut as this wiki article puts it. — Preceding unsigned comment added by 81.78.138.229 (talk) 14:47, 16 February 2023 (UTC)
Debate on lead artist impression photo featuring bending light
In recent weeks, user Lithopsian has issued a complaint about the appropriateness of this image
as being a good artist's impression of a neutron star. The guideline Wikipedia:Artist's_impressions_of_astronomical_objects describes general criteria for including both government agency produced and third-party made artists' impressions of astronomical objects. According to NASA, a neutron star has enough gravity in such a small space that it bends lights similar to a black hole.[2]https://www.nasa.gov/feature/goddard/2021/nasa-s-nicer-probes-the-squeezability-of-neutron-stars The image is edited by myself from a NASA image of a black hole, but according to the NASA website it's a realistic depiction of a neutron star (with gravitational lensing) from a copyright-free source. In the past (years ago) I've uploaded space engine pictures that were deleted due to Wiki's policy. The image I've generated using editing software is public domain and has been on the Neutron Star article for nearly two years.
Lastly, Wikipedia's ASTROART guidelines are a general template but clearly state not absolute, meaning on a case-by-case basis good faith exceptions are allowed. I believe this case is applicable and request that this image be accepted back into the Neutron Star lead article. Raphael.concorde (talk) 15:34, 13 April 2023 (UTC)
The guideline is there for a reason. It was the result of discussion and essentially consensus. You are certainly free to ignore it, but should at the very least take account of what it says. If you do ignore it and don't present a very good reason why, you should expect some push-back. The guideline is there to prevent artistic impressions that essentially fall foul of Wikipedia's rules on verifiability, that is that are not directly supported by reliable sources (a blatant example would be an exoplanet image showing cloud patterns or colours that are not known to exist). Images from "official" sources are considered automatically to be reliable depictions based on accurate consensus knowledge, although many of them are actually rather "speculative" too. It seems to me that a claim that a neutron star looks a lot like a black hole, and then producing an artistic impression effectively copied from an artistic impression of a black hole fails all sorts of WP:OR and WP:SYNTHESIS tests, exactly the sort of thing the guideline is there to prevent. Lithopsian (talk) 13:17, 14 April 2023 (UTC)
So you're basically saying that my edited photo is "amateur" or "hobbyist" and it's not appropriate to meet the criteria listed in all the guidelines? Also, please explain why the photo was able to be used in the article for nearly two years without a hitch. I know nothing lasts forever but surely yourself or others may have identified its so-called "flaws". Here is another example of a self-made photo of a black hole that was published as original work by a researcher within CERN (the user/uploader worked for the organisation) , and by coincidence, I had an internship there. Also, other science articles such as this one [1] has used the image I edited.
To conclude, I do acknowledge that this is original work, but if its one that has been reviewed and approved by others on this article for so long (including use by third party science websites) that this constitutes an exception to the rule in Wikipedia:Artist's_impressions_of_astronomical_objects and related. I believe that your argument is simply a personal opinion on how you interpret the guidelines, which are not absolute.Raphael.concorde (talk) 14:39, 14 April 2023 (UTC)
I just noticed this discussion and am trying to understand the situation here. It looks like the original source of this image is a NASA press release with an illustration of an accretion disk and corona around a supermassive black hole in the Seyfert galaxy Markarian 335. From what I can gather, this NASA illustration was taken and modified to change the black hole to make it look white instead of black, along with some other modifications, and then the modified image was given the title "Artist's impression of a neutron star bending light”. Is that correct? If so, this doesn’t seem like something that would satisfy the WP:ASTROART guidelines. Aldebarium (talk) 15:45, 14 April 2023 (UTC)
Yeah thats right, but it was used in the article for nearly two years, giving the impression it would be okay. According to what I've written in the above paragraphs, a neutron star does indeed bend light very similarly just like a black hole. I've added a ref link to supporting NASA article. Raphael.concorde (talk) 16:12, 14 April 2023 (UTC)
Thank you for the reply. I would still prefer to remove the illustration from the WP article, for the reason that taking a reliable source's illustration of an AGN black hole and accretion disk and modifying the illustration doesn't really make it a reliable source illustration of a neutron star. Aldebarium (talk) 18:23, 14 April 2023 (UTC)
Endorse removal its an image of a black hole, with a neutron star placed in the centre. This is not a realistic illustration of a neutron star. It fails the first criterion of the guideline, is misleading, and should go. Polyamorph (talk) 18:41, 8 September 2023 (UTC)
> Neutron star material is remarkably dense: a normal-sized matchbox containing neutron-star material would have a weight of approximately 3 billion tonnes, the same weight as a 0.5-cubic-kilometer chunk of the Earth (a cube with edges of about 800 meters) from Earth's surface.
Some back of the envelope math makes me think this is wrong. If the cube is 500m to the side, then that's 500x500x500 = 125,000,000 (125 million) cubic meters. 3,000,000,000 / 125,000,000 = 24.
Does a cubic meter of earth's surface weigh 24 tons? That's about 5 wheelbarrows' worth of dirt. Data is being misused here somehow. Aerovistae (talk) 18:42, 18 September 2023 (UTC)
An 800m cube has a volume of 800x800x800 cubic meters: 512 million cubic meters, seems like about 0.5 cubic kilometers. One cubic meter of "average" Earth material weights about five tons, so the matchbox of neutron star doesn't quite get there, but "dirt" from at or near the surface is much less, more like two tons or even less. Everything seems close enough to me. Not sure why you started working with a 500m cube: although "0.5-cubic-kilometer" could be considered ambiguous, it is clarified by the actual 800m size of the cube. Lithopsian (talk) 19:12, 18 September 2023 (UTC)
@Greg L: I responded there. Thanks for the heads up. If more of this sort of behavior continues, please let me know here or on my talk page which I will finally set up. MLee1957 (talk) 20:25, 3 December 2023 (UTC)
