Talk:Tolman–Oppenheimer–Volkoff limit

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I've created a redirect page from the abbreviation "TOV limit" to here. Mostly this is a convenience for edit summaries and so forth, but it should be handy elsewhere too. --Christopher Thomas 06:32, 25 February 2006 (UTC)

Schwarzschild radius
How does this article relate to the Schwarzschild radius? http://en.wikipedia.org/wiki/Schwarzschild_radius Should there be a connection of ideas between these two ideas?

Reddwarf2956 (talk) 19:24, 31 August 2009 (UTC)

The TOV limit indicates the minimum mass of a stellar black hole. The minimum Schwarzschild radius of a stellar black hole can be derived from this:
 * $$ r_s = \frac{2 M_{TOV} G}{c^2} $$

Pulu (talk) 23:57, 6 December 2017 (UTC)

A large neutron star does not collapse into a black hole
The article states: "most astrophysicists assume, in the absence of evidence to the contrary, that a neutron star above the limit collapses directly into a black hole." All observed neutron stars have a maximum mass of about 2.0 SM. All observed black holes have a minimum mass of 5 SM. If any 2.0 SM neutron star accretes mass, the mass equivalent gets ejected as gamma rays. Neutron stars do not become black holes unless they get absorbed by an already existing black hole. 72.69.11.171 (talk) 01:35, 2 August 2014 (UTC)BG

Here's a list of known neutron stars and their masses:. It shows that neutron stars do not have masses that high. Pulu (talk) 01:47, 7 December 2017 (UTC)


 * The product of neutron star merger GW170817 had a mass close to 2.7 SM after GW emission, and it didn't emit 0.7 SM of gamma radiation. WolfmanSF (talk) 05:36, 5 February 2019 (UTC)
 * It is unclear what is upper mass for NS. If it is exactly 3 SM or even 2.9 it should'nt. Need more observation data.213.24.134.17 (talk) 17:36, 21 April 2021 (UTC)

Table of High Mass Neutron Stars
It's bothered me for a while that Wikipedia has lists of most massive stars and most massive black holes but not one for neutron stars, so I figured this article seemed to be a good place to create one as it is relevant to the subject matter. My thanks to WolfmanSF for fixing the table so that it can be sorted by mass. I've tried to include every candidate which realistically could claim to be the most massive neutron star known; there are ten now, and I don't want to add any more unless necessary as the table is already looking a little bloated. Sonicology (talk) 15:04, 21 September 2019 (UTC)

I've replaced the Location column of the table with a column for describing the stellar classification of the companion star. I think location was superfluous, as anyone who needs the coordinates would surely know how to look them up on SIMBAD. The companion class column makes it easier to tell the nature of the companion star or object at a glance, makes the table more visually pleasing, and reduces the size of the entries in the Notes column by removing the need to describe the nature of the companion there. --Sonicology (talk) 06:38, 5 November 2019 (UTC)

According to the reference listed (James M. Lattimer 2015), the mass of PSR J1748-2021B is more like an upper limit rather than an exact mass measurement. "The object PSR J1748-2021B has an estimated mass of  2.74±0.21Msun,  but its inclination angle is unknown and the errors reflect the 1σ uncertainty. Measurement of i could easily reduce the mass to 1.5Msun." I suggest there should be a note regarding this fact. Aardwolf first (talk) 22:34, 9 December 2019 (UTC)
 * It appears that if the rate of advance of the periastron is based solely on general relativity effects, it gives the total mass of the system (see eq. 1 here), so since a more inclined orbit is consistent with a more massive companion to account for the NS radial velocities, that implies a less massive primary NS. WolfmanSF (talk) 06:47, 10 December 2019 (UTC)
 * Correct, this is the case for all entries measured by rate of advance of periastron. It's part of the reason I felt it was important to include how the mass value was derived. Vela X-1 for example is at the bottom of the table at 1.88 solar masses, but the reference notes that a different inclination gives a mass of 2.27. Ultimately I went with 1.88 because that is the value commonly cited in the literature, and the value the researchers felt best fitted the data. The same is true for PSR J1748-2021B. Personally I would be against adding a caveat for the stated mass figure; it's well understood in astronomy that values are subject to change as better data becomes available, you only have to look at the constant editing of the lists of most massive and most luminous stars to see that in action. With that said I'm not going to get into an edit war over it, although for the sake of consistency I would suggest that if you must leave in the ≤ symbol then we should add similar symbols for all entries measured by rate of advance of periastron (for example adding ≥ for Vela X-1) Sonicology (talk) 08:59, 10 December 2019 (UTC)

Significant part of the article is not about the TOV Limit but the maximum mass
This article seems to confuse the TOV Limit with the maximum mass of a neutron star. This is wrong (see Rezola 2018 https://iopscience.iop.org/article/10.3847/2041-8213/aaa401/meta ). The entire third paragraph about GW170807 and the lists of neutron stars and black holes is about the maximum mass which can include rotating neutron stars (which are explicitly excluded from the TOV limit).

I removed the incorrect parts but I also heavily recommend removing the list of most massive neuntron stars, least massive black holes and the mass gap. Since those parts heavily imply they are related to the TOV (which is not the case). Highlow9 (talk) 4 January 2023.


 * Thanks for starting this discussion. This is not a heavily-edited article, although there are quite a number of watchers, so if you don't get much response then you might want to mention the discussion at relevant project pages: Wikipedia talk:WikiProject Physics and perhaps Wikipedia talk:WikiProject Astronomy.  Lithopsian (talk) 14:56, 5 January 2023 (UTC)


 * The Rezola article explicitly compares to the TOV limit in their discussion of maximum mass, so I don't understand why "this is wrong". Johnjbarton (talk) 18:21, 5 January 2024 (UTC)
 * Well the intro paragraph does sound "wrong", in that it starts with TOV then veers into maximum mass without explanation.
 * Is there are page on Neutron mass limits? Johnjbarton (talk) 18:29, 5 January 2024 (UTC)
 * You could reorganise the subsections under https://en.wikipedia.org/wiki/Neutron_star#Properties
 * There's currently a subsection on Mass and temperature. This could be divided & expanded. I suggest making use of this article in the temperature section: https://academic.oup.com/mnras/article/442/4/3484/1357581 MathewMunro (talk) 10:57, 7 January 2024 (UTC)

V723 Monocerotis is not a black hole
Follow-up work in 2022 argued that V723 Monocerotis does not contain a black hole, but is a mass-transfer binary containing a red giant and a subgiant star that has been stripped of much of its mass. Voproshatel (talk) 08:00, 3 April 2024 (UTC)

HR 6819 (QV Tel) is not a black hole
Later work found another explanation, namely that the moving star is actually much lighter, but emitting a similar amount of light. In that case there is no need to invoke the presence of a black hole. This explanation is supported by the detection of motion in the hydrogen disk surrounding the other star, with the 40-day period. The model with a Be star and a stripped giant star, but no black hole, has been confirmed in a further paper published in 2022. Voproshatel (talk) 08:07, 3 April 2024 (UTC)

GX 339-4 has a slightly different mass.
From spectroscopic measurements, the mass of the black-hole GX 339-4 was found to be at least of 5.8 solar masses. Voproshatel (talk) 08:17, 3 April 2024 (UTC)

GRO J0422+32/V518 Persei has a significantly smaller mass, so it is not in mass gap
Analysis in 2012 calculated a mass of. Voproshatel (talk) 08:30, 3 April 2024 (UTC)