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Some of the masses in the table for the companion object are impossibly small. I notice Cygnus X-1 in particular, where the companion star is an O9.7Iab, and must have a mass of roughly ≥20 solar masses. The table gives 0.25, and I think this might be the so-called mass function. The Uhuru X-ray source 4U 1543-475 is a similar case, but I do not know the lower limit.
Comment: The lower limit for a start to turn into a black hole is probably something like 20 solar masses. 8 solar masses is the limit for a supernova. At this mass a core of more than 1.44 solar masses remains, above the Chandrasekhar limit. The limiting mass of a neutron star is unknown (only that most neutron stars have a mass close the 1.4 solar masses), and it is also unkown how much of the mass will end up in the compact object in a supernova explosion. Therefore, the exact mass a star must minimally have to end in a black hole is unknown as well. —Preceding unsigned comment added by 212.123.164.6 ( talk) 19:50, 27 July 2010 (UTC)
I don't have time to check all these right now, but will put it on my list (meaning it could be a while). For now I have changed the "Mass" column heading to be BH mass, and the other to be "Companion Mass", but estimates for the mass of the optical companion need to be distinguished from the mass functions (which are easier to determine observationally, but only constrain the masses, don't determine them unless the orbital inclination is known). If the mass function is meant, then the column heading should so indicate, and define it (we don't seem to have an article that does that, but I only checked the article on binary stars). Wwheaton ( talk) 00:05, 10 April 2008 (UTC)
The end of the first paragraph reads "with a mass 3.8 solar masses and a diameter of only 9 kilometers (15 miles)." I suspect the numbers are reversed since 15 kilometers is roughly 9 miles.
The article currently states:
"A black hole can only have three fundamental properties: mass, electric charge and angular momentum (spin)."
Wouldn't a black hole also have a velocity in space, relative to other objects? Gravitational attraction is a two-way street, after all.
-- Rogermw ( talk) 22:00, 27 October 2009 (UTC)
Im not challenging the "citation needed" tags, just so its clear. But there seem to be a silly amount of them. Should we just replace it with a template stating such? Since theres not many people who could really write up the accurate information, i think the citation needed template would make the article, flawed though it may be, much more readable. Not going to change it right away incase there are disagreements. 74.132.249.206 ( talk) 07:12, 9 August 2011 (UTC)
The article states: "The process is observed as a supernova explosion". 1) This sentence is only partially true: BHs can indeed be formed via prompt collapse, i.e. no intermediate protoneutron star stage. Within this scenario, no SN happens: matter directly collapses into the BH. For reference: http://arxiv.org/abs/1110.1635 2) Also, it is not very correct to speak about "observing" the process. Shesinastro ( talk) 21:45, 21 October 2011 (UTC)
The article says:
Since 2007 there have been some claims of significantly larger stellar black holes. Are these solid enough to be worth adding? This NASA press release discusses an object claimed to be between 24 and 33 solar masses, citing a paper to that effect, which seems reasonably legit. I'm not knowledgeable enough about the literature here to feel comfortable adding it, though. Our article in general already seems a little bit hodge-podge on these kinds of claims; do any recent survey papers of this area exist that we could cite for a more solid overview? -- Delirium ( talk) 16:02, 17 December 2011 (UTC)
The arcticle states:
"In February 2016, a black hole of 62±4 solar masses was discovered in gravitational waves as it formed in a merger event of two smaller black holes."
Wouldn't this item more properly belong on the page for Intermediate-mass black holes? The formation process, a merger, would seem more important than the exact mass of the resulting black hole (i.e. above an arbitrary 100 M_sol). The object formed is also substantially more massive than the most massive previously known stellar black hole. Pnikula ( talk) 06:43, 12 February 2016 (UTC)
This is probably where that "threshold" of 100 M☉ (the threshold that is being questioned) was mentioned. -- Mike Schwartz ( talk) 23:11, 27 April 2016 (UTC)An intermediate-mass black hole (IMBH) is a hypothetical class of black hole with mass in the range 100 to one million citation needed solar masses: significantly more than stellar black holes but less than supermassive black holes.
The article states:
"In February 2016, a black hole of 62±4 solar masses was discovered in gravitational waves as it formed in a merger event of two smaller black holes."
IMHO that is wrong. The paper about the discovery was published (and the public announcements were released) "In February 2016"; but the "discovering" itself (by the LIGO project) had taken place during September 2015.
So, IMHO, either the "as of" date in that sentence (the sentence that is "blockquote"ed above) should be changed to "September 2015" -- as is clearly supported by many reliable sources, such as those that are cited in the article about First observation of gravitational waves (in the section about " The GW150914 event") -- or else, the verb in that sentence should be saying something about when the paper was published, and/or when the announcement was made publicly, instead of talking about when the large black hole was "discovered".
(Comment: the name "GW150914" itself -- as in " The GW150914 event" -- is derived from the date "September 14, 2015".)
(another comment): The footnote or "reference" will not have to change. It already points to a reliable source with a URL of http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.061102 and -- in the full text of that paper [which is available at that URL, even though part of the URL might "seem" to be implying that it is (only) the "abstract"!] -- it clearly states, at the beginning of section "[Roman numeral] II" (the section with a title of "II. OBSERVATION"), that
On September 14, 2015 at 09:50:45 UTC, the LIGO Hanford, WA, and Livingston, LA, observatories detected the coincident signal GW150914 shown in Fig. 1.
...So, actually, making the "edits" (changes) suggested here, will make this Wikipedia article more consistent (not less) with what that source says.
"In September 2015, a black hole of 62±4 solar masses was discovered in gravitational waves as it formed in a merger event of two smaller black holes."
"In February 2016, it was announced that the LIGO project had detected, via gravitational waves, the formation of a black hole of 62±4 solar masses in a merger event of two smaller black holes."
I vote for the first option (the "date change"). -- Mike Schwartz ( talk) 18:04, 19 April 2016 (UTC)
With no dissent (at least, on this "Talk:" page) after about a week, the first option (the "date change") was implemented by this simple edit.
-- Mike Schwartz ( talk) 22:53, 27 April 2016 (UTC)
The article Supermassive black hole estimates the tidal force at the event horizon of a supermassive black hole as roughly similar to that experienced on Earth. The present article needs a similar estimate for stellar-sized BHs. David Spector ( talk) 16:02, 20 August 2018 (UTC)
I plan to put this into the article soon as you recommended, but have held back so far because the original data point is extremely vague. "About the same" might be off by as much as a factor of 10. I could do the math properly by just starting with the tidal force equation, but havent gotten around to it yet. — Soap — 22:55, 10 December 2019 (UTC)
I have read that "108 black holes are estimated to reside within the Milky Way". A reader might get the impression from the article that there are much fewer. Could someone knowledgeable write something about the expected abundance? Keith McClary ( talk) 22:34, 19 March 2019 (UTC)
Schwarzschild_Radius is given by
Computationally, =(2*(6.67408*10^-11)*M*(1.9884*10^30))/((299792458)^2)/10^3
Name | BHC_Solar_mass (M☉) |
Lower_Limit | Schwarzschild_Radius (in Km) |
---|---|---|---|
A0620-00/V616 Mon | 11 ± 2 | 9 | 26.578 |
GRO J1655-40/V1033 Sco | 6.3 ± 0.3 | 6 | 17.719 |
XTE J1118+480/KV UMa | 6.8 ± 0.4 | 6.4 | 18.901 |
Cyg X-1 | 11 ± 2 | 9 | 26.579 |
GRO J0422+32/V518 Per | 4 ± 1 | 3 | 8.860 |
GRO J1719-24 | ≥4.9 | 4.9 | 14.471 |
GS 2000+25/QZ Vul | 7.5 ± 0.3 | 7.2 | 21.263 |
V404 Cyg | 12 ± 2 | 10 | 29.531 |
GRS 1124-683/GU Mus | 7.0 ± 0.6 | 6.4 | 18.900 |
XTE J1550-564/V381 Nor | 9.6 ± 1.2 | 8.4 | 24.806 |
4U 1543-475/IL Lupi | 9.4 ± 1.0 | 8.4 | 24.806 |
XTE J1819-254/V4641 Sgr | 7.1 ± 0.3 | 6.8 | 20.081 |
GRS 1915+105/V1487 Aql | 14 ± 4.0 | 10 | 29.531 |
XTE J1650-500 | 9.7 ± 1.6 | 8.1 | 23.920 |
GW150914 (62 ± 4) M☉ | 36 ± 4 | 32 | 94.500 |
GW151226 (21.8 ± 3.5) M☉ | 14.2 ± 6 | 8 | 23.625 |
GW170104 (48.7 ± 5) M☉ | 31.2 ± 7 | 24 | 70.875 |
Bkpsusmitaa ( talk) 14:48, 2 December 2018 (UTC)
This article appears to be ambitious in range but it has been identified in this talk section as early in its development.
Is there a standard way to alert the Wikipedia reader when a source is Start-class in the way Stub-class articles are flagged?
It may even prompt a student or professor to make it an assignment. ReedScarce ( talk) 17:54, 24 February 2022 (UTC)
Analysis in 2012 calculated a mass of 2.1 M☉. [1] Voproshatel ( talk) 08:30, 3 April 2024 (UTC) Voproshatel ( talk) 08:33, 3 April 2024 (UTC)
References
This is the
talk page for discussing improvements to the
Stellar black hole article. This is not a forum for general discussion of the article's subject. |
Article policies
|
Find sources: Google ( books · news · scholar · free images · WP refs) · FENS · JSTOR · TWL |
![]() | This ![]() It is of interest to the following WikiProjects: | ||||||||||||||||||||||||||
|
Some of the masses in the table for the companion object are impossibly small. I notice Cygnus X-1 in particular, where the companion star is an O9.7Iab, and must have a mass of roughly ≥20 solar masses. The table gives 0.25, and I think this might be the so-called mass function. The Uhuru X-ray source 4U 1543-475 is a similar case, but I do not know the lower limit.
Comment: The lower limit for a start to turn into a black hole is probably something like 20 solar masses. 8 solar masses is the limit for a supernova. At this mass a core of more than 1.44 solar masses remains, above the Chandrasekhar limit. The limiting mass of a neutron star is unknown (only that most neutron stars have a mass close the 1.4 solar masses), and it is also unkown how much of the mass will end up in the compact object in a supernova explosion. Therefore, the exact mass a star must minimally have to end in a black hole is unknown as well. —Preceding unsigned comment added by 212.123.164.6 ( talk) 19:50, 27 July 2010 (UTC)
I don't have time to check all these right now, but will put it on my list (meaning it could be a while). For now I have changed the "Mass" column heading to be BH mass, and the other to be "Companion Mass", but estimates for the mass of the optical companion need to be distinguished from the mass functions (which are easier to determine observationally, but only constrain the masses, don't determine them unless the orbital inclination is known). If the mass function is meant, then the column heading should so indicate, and define it (we don't seem to have an article that does that, but I only checked the article on binary stars). Wwheaton ( talk) 00:05, 10 April 2008 (UTC)
The end of the first paragraph reads "with a mass 3.8 solar masses and a diameter of only 9 kilometers (15 miles)." I suspect the numbers are reversed since 15 kilometers is roughly 9 miles.
The article currently states:
"A black hole can only have three fundamental properties: mass, electric charge and angular momentum (spin)."
Wouldn't a black hole also have a velocity in space, relative to other objects? Gravitational attraction is a two-way street, after all.
-- Rogermw ( talk) 22:00, 27 October 2009 (UTC)
Im not challenging the "citation needed" tags, just so its clear. But there seem to be a silly amount of them. Should we just replace it with a template stating such? Since theres not many people who could really write up the accurate information, i think the citation needed template would make the article, flawed though it may be, much more readable. Not going to change it right away incase there are disagreements. 74.132.249.206 ( talk) 07:12, 9 August 2011 (UTC)
The article states: "The process is observed as a supernova explosion". 1) This sentence is only partially true: BHs can indeed be formed via prompt collapse, i.e. no intermediate protoneutron star stage. Within this scenario, no SN happens: matter directly collapses into the BH. For reference: http://arxiv.org/abs/1110.1635 2) Also, it is not very correct to speak about "observing" the process. Shesinastro ( talk) 21:45, 21 October 2011 (UTC)
The article says:
Since 2007 there have been some claims of significantly larger stellar black holes. Are these solid enough to be worth adding? This NASA press release discusses an object claimed to be between 24 and 33 solar masses, citing a paper to that effect, which seems reasonably legit. I'm not knowledgeable enough about the literature here to feel comfortable adding it, though. Our article in general already seems a little bit hodge-podge on these kinds of claims; do any recent survey papers of this area exist that we could cite for a more solid overview? -- Delirium ( talk) 16:02, 17 December 2011 (UTC)
The arcticle states:
"In February 2016, a black hole of 62±4 solar masses was discovered in gravitational waves as it formed in a merger event of two smaller black holes."
Wouldn't this item more properly belong on the page for Intermediate-mass black holes? The formation process, a merger, would seem more important than the exact mass of the resulting black hole (i.e. above an arbitrary 100 M_sol). The object formed is also substantially more massive than the most massive previously known stellar black hole. Pnikula ( talk) 06:43, 12 February 2016 (UTC)
This is probably where that "threshold" of 100 M☉ (the threshold that is being questioned) was mentioned. -- Mike Schwartz ( talk) 23:11, 27 April 2016 (UTC)An intermediate-mass black hole (IMBH) is a hypothetical class of black hole with mass in the range 100 to one million citation needed solar masses: significantly more than stellar black holes but less than supermassive black holes.
The article states:
"In February 2016, a black hole of 62±4 solar masses was discovered in gravitational waves as it formed in a merger event of two smaller black holes."
IMHO that is wrong. The paper about the discovery was published (and the public announcements were released) "In February 2016"; but the "discovering" itself (by the LIGO project) had taken place during September 2015.
So, IMHO, either the "as of" date in that sentence (the sentence that is "blockquote"ed above) should be changed to "September 2015" -- as is clearly supported by many reliable sources, such as those that are cited in the article about First observation of gravitational waves (in the section about " The GW150914 event") -- or else, the verb in that sentence should be saying something about when the paper was published, and/or when the announcement was made publicly, instead of talking about when the large black hole was "discovered".
(Comment: the name "GW150914" itself -- as in " The GW150914 event" -- is derived from the date "September 14, 2015".)
(another comment): The footnote or "reference" will not have to change. It already points to a reliable source with a URL of http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.061102 and -- in the full text of that paper [which is available at that URL, even though part of the URL might "seem" to be implying that it is (only) the "abstract"!] -- it clearly states, at the beginning of section "[Roman numeral] II" (the section with a title of "II. OBSERVATION"), that
On September 14, 2015 at 09:50:45 UTC, the LIGO Hanford, WA, and Livingston, LA, observatories detected the coincident signal GW150914 shown in Fig. 1.
...So, actually, making the "edits" (changes) suggested here, will make this Wikipedia article more consistent (not less) with what that source says.
"In September 2015, a black hole of 62±4 solar masses was discovered in gravitational waves as it formed in a merger event of two smaller black holes."
"In February 2016, it was announced that the LIGO project had detected, via gravitational waves, the formation of a black hole of 62±4 solar masses in a merger event of two smaller black holes."
I vote for the first option (the "date change"). -- Mike Schwartz ( talk) 18:04, 19 April 2016 (UTC)
With no dissent (at least, on this "Talk:" page) after about a week, the first option (the "date change") was implemented by this simple edit.
-- Mike Schwartz ( talk) 22:53, 27 April 2016 (UTC)
The article Supermassive black hole estimates the tidal force at the event horizon of a supermassive black hole as roughly similar to that experienced on Earth. The present article needs a similar estimate for stellar-sized BHs. David Spector ( talk) 16:02, 20 August 2018 (UTC)
I plan to put this into the article soon as you recommended, but have held back so far because the original data point is extremely vague. "About the same" might be off by as much as a factor of 10. I could do the math properly by just starting with the tidal force equation, but havent gotten around to it yet. — Soap — 22:55, 10 December 2019 (UTC)
I have read that "108 black holes are estimated to reside within the Milky Way". A reader might get the impression from the article that there are much fewer. Could someone knowledgeable write something about the expected abundance? Keith McClary ( talk) 22:34, 19 March 2019 (UTC)
Schwarzschild_Radius is given by
Computationally, =(2*(6.67408*10^-11)*M*(1.9884*10^30))/((299792458)^2)/10^3
Name | BHC_Solar_mass (M☉) |
Lower_Limit | Schwarzschild_Radius (in Km) |
---|---|---|---|
A0620-00/V616 Mon | 11 ± 2 | 9 | 26.578 |
GRO J1655-40/V1033 Sco | 6.3 ± 0.3 | 6 | 17.719 |
XTE J1118+480/KV UMa | 6.8 ± 0.4 | 6.4 | 18.901 |
Cyg X-1 | 11 ± 2 | 9 | 26.579 |
GRO J0422+32/V518 Per | 4 ± 1 | 3 | 8.860 |
GRO J1719-24 | ≥4.9 | 4.9 | 14.471 |
GS 2000+25/QZ Vul | 7.5 ± 0.3 | 7.2 | 21.263 |
V404 Cyg | 12 ± 2 | 10 | 29.531 |
GRS 1124-683/GU Mus | 7.0 ± 0.6 | 6.4 | 18.900 |
XTE J1550-564/V381 Nor | 9.6 ± 1.2 | 8.4 | 24.806 |
4U 1543-475/IL Lupi | 9.4 ± 1.0 | 8.4 | 24.806 |
XTE J1819-254/V4641 Sgr | 7.1 ± 0.3 | 6.8 | 20.081 |
GRS 1915+105/V1487 Aql | 14 ± 4.0 | 10 | 29.531 |
XTE J1650-500 | 9.7 ± 1.6 | 8.1 | 23.920 |
GW150914 (62 ± 4) M☉ | 36 ± 4 | 32 | 94.500 |
GW151226 (21.8 ± 3.5) M☉ | 14.2 ± 6 | 8 | 23.625 |
GW170104 (48.7 ± 5) M☉ | 31.2 ± 7 | 24 | 70.875 |
Bkpsusmitaa ( talk) 14:48, 2 December 2018 (UTC)
This article appears to be ambitious in range but it has been identified in this talk section as early in its development.
Is there a standard way to alert the Wikipedia reader when a source is Start-class in the way Stub-class articles are flagged?
It may even prompt a student or professor to make it an assignment. ReedScarce ( talk) 17:54, 24 February 2022 (UTC)
Analysis in 2012 calculated a mass of 2.1 M☉. [1] Voproshatel ( talk) 08:30, 3 April 2024 (UTC) Voproshatel ( talk) 08:33, 3 April 2024 (UTC)
References