This is the
talk page for discussing improvements to the
Canopus 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: | |||||||||||||
|
I added the detail of the star's ancient role as a 'southern pole-star', and turned the mention of Canopus in Argos into a working link. I also created subheaders and moved a couple of paragraphs to a more logical order.
-- GwydionM 19:20, 17 January 2006 (UTC)
"About 90,000 years ago, Sirius moved close enough that it became brighter than Canopus, and that will remain the case for another 210,000 years. But in 480,000 years, Canopus will once again be the brightest" - so what happens between 210k AD and 480k AD? — Preceding unsigned comment added by 92.14.30.2 ( talk) 23:52, 5 March 2012 (UTC)
Is identification of Canopus as the Arrakis in Frank Herbert's Dune correct, from the text of the novel itself? Arrakis is one form of the Arabic name for Mu Draconis, HR 6370. BSVulturis 22:06, 19 September 2006 (UTC)
Canopus is not "yellowish white". It's a white star. Look at the photo included--white with a tinge of blue. —Preceding unsigned comment added by 192.30.202.20 ( talk) 21:32, 23 November 2007 (UTC)
Canopus is a F-class supergiant star and essentially white when seen with the naked eye, though these stars are considered to be yellowish-white when viewed in greater detail.
Remember the stars colour was first examined by using a spectrum. The colours are O(blue) B(blue-white) A(white) F(yellow-white) G(yellow) K(orange) M(red), or Oh Be A Fine Girl and Kiss Me! Canopus is and F type star (yellow-white) while our Sun is a G(yellow). —Preceding unsigned comment added by 125.254.66.213 ( talk) 05:27, 5 July 2008 (UTC)
Would it be unreasonable of me to edit this by inserting "about 5 nano radians" in parentheses at the end of the sentence, like so?
-- arkuat (talk) 04:33, 8 June 2008 (UTC)
The article says Canopus is 65 times the size that of the sun and yet latter says that if placed in our solar system it would only come out to three quarters to Mercury's orbit. Those two things seem to conflict with each other. Mercury is very close to the sun. How can Canopus be 65 times the size of the sun and yet would only not envelop the inner planets?
-- 69.37.140.100 ( talk) 01:01, 8 February 2009 (UTC)
This isn't the only problem with the article. I agree with the OP regarding the size given as 65x Sol or 0.6 AU which would engulf Mercury and have Venus skimming over it's surface. Earlier in the same section it states "...distance estimates for the star varied widely, from 96 light years to 1200 light years. Had the latter distance been correct, Canopus would have been one of the most luminous stars in our galaxy." The "latter distance" is 1200 ly which is further than the article states it's distance is now, it should imply that if the star was only 96 ly it would be the most luminous. — Preceding unsigned comment added by 207.255.204.36 ( talk) 08:05, 7 October 2011 (UTC)
In the paragraph Etymology, Canopus appears to be known as Laorenxing in Chinese. I find this surprising as, to my knowledge, the sound "r" is not present in chinese language. Has this been checked by some chinese mother tongue expert?-- Franco3450 ( talk) 14:41, 9 April 2009 (UTC)
In an effort to make the section on the visibility of this star more universal, I chose to show a location from which Canopus would not be visible (Richmond, Virginia) and one in which it would be visible (Atlanta). Many people in the eastern USA don't realize how far south San Francisco is... but they realize well enough how far south Richmond and Atlanta are.
Universal? Really? This is absurdly American-centric. — Preceding unsigned comment added by 92.14.30.2 ( talk) 23:54, 5 March 2012 (UTC)
About 90,000 years ago, Sirius moved close enough that it became brighter than Canopus, and that will remain the case for another 210,000 years. But in 480,000 years, Canopus will once again be the brightest, and will remain so for a period of about 510,000 years.
I read this in the article and seriously doubt if it is something we can say with 100 percent certainty. Canopus is so massive that it evolves very quickly, and may not exist in its current form in half a million years, especially considering that it is already off the main sequence. Statements like this should really have a verifiable source.
71.49.46.224 (
talk)
13:49, 1 June 2012 (UTC)
If the star wasn't visible to the Greeks, how did it become associated with Argo Navis before the Age of Discovery? 137.205.120.187 ( talk) 16:45, 11 November 2013 (UTC)
Name of star < name of ancient port < name of mythological pilot. And I don't see how the star is the most notable of all. The lemma Canopus should lead to the disambig.-- 94.68.128.29 ( talk) 09:20, 4 November 2015 (UTC)
Hello fellow Wikipedians,
I have just modified one external link on Canopus. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
When you have finished reviewing my changes, please set the checked parameter below to true or failed to let others know (documentation at {{
Sourcecheck}}
).
This message was posted before February 2018.
After February 2018, "External links modified" talk page sections are no longer generated or monitored by InternetArchiveBot. No special action is required regarding these talk page notices, other than
regular verification using the archive tool instructions below. Editors
have permission to delete these "External links modified" talk page sections if they want to de-clutter talk pages, but see the
RfC before doing mass systematic removals. This message is updated dynamically through the template {{
source check}}
(last update: 5 June 2024).
Cheers.— InternetArchiveBot ( Report bug) 09:27, 14 November 2016 (UTC)
The article references Lopez (1993), page 66 and gives the spectral class as A9 II; the also referenced Cruzalebes (2013), p. 12 gives F0 II (both in infobox); but the Hiparcos catalogue (1997) gives it as F0 Ib ( [1] ). What is it? At least the values should agree with referenced sources. Kipala ( talk) 12:41, 31 December 2017 (UTC)
Hello fellow Wikipedians,
I have just modified one external link on Canopus. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
When you have finished reviewing my changes, you may follow the instructions on the template below to fix any issues with the URLs.
This message was posted before February 2018.
After February 2018, "External links modified" talk page sections are no longer generated or monitored by InternetArchiveBot. No special action is required regarding these talk page notices, other than
regular verification using the archive tool instructions below. Editors
have permission to delete these "External links modified" talk page sections if they want to de-clutter talk pages, but see the
RfC before doing mass systematic removals. This message is updated dynamically through the template {{
source check}}
(last update: 5 June 2024).
Cheers.— InternetArchiveBot ( Report bug) 09:20, 23 January 2018 (UTC)
I'm running short of (referenced) things to add to the article. Either I'm not looking hard enough or there isn't a lot else out there. It would be nice to write some more about evolution, but I can't find references that discuss it. It is probably a super-AGB star, although has also been considered as a low-mass supergiant. Its evolution is balanced between becoming an exotic type of white dwarf or an unusual type of supernova, but not many people are going on paper to discuss it. Lithopsian ( talk) 11:41, 24 May 2020 (UTC)
@ Lithopsian:, isn't Canopus on warm side not cool side of instability strip? Cas Liber ( talk · contribs) 21:16, 13 June 2020 (UTC)
Also - the bit about precession and it, Achernar and the south celestial pole need a rewrite and better/reliable sourcing. Anything else? Cas Liber ( talk · contribs) 21:44, 4 September 2020 (UTC) @ Lithopsian: - one thing that might be good is what exactly it is about the spectrum that tells us it's already been a RSG and is in a blue loop....(?) Cas Liber ( talk · contribs) 22:19, 4 September 2020 (UTC)
Also this paper already used (gives the high abs mag value in infobox). Helps explain (later outdated) view that it is 15000 times as luminous as the Sun. Cas Liber ( talk · contribs) 14:04, 5 September 2020 (UTC)
The Observation section of the article contains this paragraph (which I've already trimmed):
Is this interesting or not? I don't think this content is worthy of such a long paragraph, but what do others think? Attic Salt ( talk) 03:05, 30 May 2020 (UTC)
Thanks for asking me to join :-) My eye was caught by the sentence "Canopus pulsates slightly with a period of 6.9 d. " I have not been able to find any papers to confirm this. Those old radial velocity variation from 1906 are probably not worth mentioning. By the way, RV variations can have other causes so if you do keep the reference, I would replace "pulsates" by "varies". Timb66 ( talk) 07:00, 15 June 2020 (UTC)
Actually the whole name bit needs an overhaul. R.H.Allen was not a terrific researcher but is all we have on lots of stuff. The section needs rejigging chronologically but I wish we could find better sources. Hence I found this which talks of Eudoxus of Cnidus going to observe it but not naming it (see p. 88). Cas Liber ( talk · contribs) 10:49, 7 September 2020 (UTC)
First the paragraph says From the imperial capital Chang'an, the star made a low transit across the southern sky, indicating true south to observers, and was often obscured by clouds. Then just one sentence later, it says ...it cannot be seen from the Chinese capital of Chang'an. Which is it?! According to the lat/long listed for the current incarnation of the city, it's at 34°15′54″N 108°57′14″E. Earlier in the article, and discussed here in Talk above, it's stated in theory the northern limit of visibility is latitude 37° 18′N with some variations due to altitude. Does anybody know a Chinese astronomer who can clarify this, please?
Corgi ( talk) 23:30, 17 December 2022 (UTC)
This paper refers to Canopus as the closest supergiant (yellow supergiant) to the Solar System, although it still cites the A9II classification. It gives it a mass of 9.81 M☉, consistent with that of a super-AGB star (as Lithopsian suggested above) and the progenitors of electron-capture supernovae (the accepted supernova lower limit is around 8.5 M☉, although this is not well defined). I've heard Kaler (who suggested a white dwarf fate for Canopus) isn't that reliable compared to other sources. Also, how come Canopus is just a bright giant (II) at 10,700 L☉ when Iota Carinae has a spectral class of A9Ib and 4,900 L☉? Stanley Joseph "Stan" ( talk) 00:58, 28 March 2024 (UTC)
This is the
talk page for discussing improvements to the
Canopus 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: | |||||||||||||
|
I added the detail of the star's ancient role as a 'southern pole-star', and turned the mention of Canopus in Argos into a working link. I also created subheaders and moved a couple of paragraphs to a more logical order.
-- GwydionM 19:20, 17 January 2006 (UTC)
"About 90,000 years ago, Sirius moved close enough that it became brighter than Canopus, and that will remain the case for another 210,000 years. But in 480,000 years, Canopus will once again be the brightest" - so what happens between 210k AD and 480k AD? — Preceding unsigned comment added by 92.14.30.2 ( talk) 23:52, 5 March 2012 (UTC)
Is identification of Canopus as the Arrakis in Frank Herbert's Dune correct, from the text of the novel itself? Arrakis is one form of the Arabic name for Mu Draconis, HR 6370. BSVulturis 22:06, 19 September 2006 (UTC)
Canopus is not "yellowish white". It's a white star. Look at the photo included--white with a tinge of blue. —Preceding unsigned comment added by 192.30.202.20 ( talk) 21:32, 23 November 2007 (UTC)
Canopus is a F-class supergiant star and essentially white when seen with the naked eye, though these stars are considered to be yellowish-white when viewed in greater detail.
Remember the stars colour was first examined by using a spectrum. The colours are O(blue) B(blue-white) A(white) F(yellow-white) G(yellow) K(orange) M(red), or Oh Be A Fine Girl and Kiss Me! Canopus is and F type star (yellow-white) while our Sun is a G(yellow). —Preceding unsigned comment added by 125.254.66.213 ( talk) 05:27, 5 July 2008 (UTC)
Would it be unreasonable of me to edit this by inserting "about 5 nano radians" in parentheses at the end of the sentence, like so?
-- arkuat (talk) 04:33, 8 June 2008 (UTC)
The article says Canopus is 65 times the size that of the sun and yet latter says that if placed in our solar system it would only come out to three quarters to Mercury's orbit. Those two things seem to conflict with each other. Mercury is very close to the sun. How can Canopus be 65 times the size of the sun and yet would only not envelop the inner planets?
-- 69.37.140.100 ( talk) 01:01, 8 February 2009 (UTC)
This isn't the only problem with the article. I agree with the OP regarding the size given as 65x Sol or 0.6 AU which would engulf Mercury and have Venus skimming over it's surface. Earlier in the same section it states "...distance estimates for the star varied widely, from 96 light years to 1200 light years. Had the latter distance been correct, Canopus would have been one of the most luminous stars in our galaxy." The "latter distance" is 1200 ly which is further than the article states it's distance is now, it should imply that if the star was only 96 ly it would be the most luminous. — Preceding unsigned comment added by 207.255.204.36 ( talk) 08:05, 7 October 2011 (UTC)
In the paragraph Etymology, Canopus appears to be known as Laorenxing in Chinese. I find this surprising as, to my knowledge, the sound "r" is not present in chinese language. Has this been checked by some chinese mother tongue expert?-- Franco3450 ( talk) 14:41, 9 April 2009 (UTC)
In an effort to make the section on the visibility of this star more universal, I chose to show a location from which Canopus would not be visible (Richmond, Virginia) and one in which it would be visible (Atlanta). Many people in the eastern USA don't realize how far south San Francisco is... but they realize well enough how far south Richmond and Atlanta are.
Universal? Really? This is absurdly American-centric. — Preceding unsigned comment added by 92.14.30.2 ( talk) 23:54, 5 March 2012 (UTC)
About 90,000 years ago, Sirius moved close enough that it became brighter than Canopus, and that will remain the case for another 210,000 years. But in 480,000 years, Canopus will once again be the brightest, and will remain so for a period of about 510,000 years.
I read this in the article and seriously doubt if it is something we can say with 100 percent certainty. Canopus is so massive that it evolves very quickly, and may not exist in its current form in half a million years, especially considering that it is already off the main sequence. Statements like this should really have a verifiable source.
71.49.46.224 (
talk)
13:49, 1 June 2012 (UTC)
If the star wasn't visible to the Greeks, how did it become associated with Argo Navis before the Age of Discovery? 137.205.120.187 ( talk) 16:45, 11 November 2013 (UTC)
Name of star < name of ancient port < name of mythological pilot. And I don't see how the star is the most notable of all. The lemma Canopus should lead to the disambig.-- 94.68.128.29 ( talk) 09:20, 4 November 2015 (UTC)
Hello fellow Wikipedians,
I have just modified one external link on Canopus. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
When you have finished reviewing my changes, please set the checked parameter below to true or failed to let others know (documentation at {{
Sourcecheck}}
).
This message was posted before February 2018.
After February 2018, "External links modified" talk page sections are no longer generated or monitored by InternetArchiveBot. No special action is required regarding these talk page notices, other than
regular verification using the archive tool instructions below. Editors
have permission to delete these "External links modified" talk page sections if they want to de-clutter talk pages, but see the
RfC before doing mass systematic removals. This message is updated dynamically through the template {{
source check}}
(last update: 5 June 2024).
Cheers.— InternetArchiveBot ( Report bug) 09:27, 14 November 2016 (UTC)
The article references Lopez (1993), page 66 and gives the spectral class as A9 II; the also referenced Cruzalebes (2013), p. 12 gives F0 II (both in infobox); but the Hiparcos catalogue (1997) gives it as F0 Ib ( [1] ). What is it? At least the values should agree with referenced sources. Kipala ( talk) 12:41, 31 December 2017 (UTC)
Hello fellow Wikipedians,
I have just modified one external link on Canopus. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
When you have finished reviewing my changes, you may follow the instructions on the template below to fix any issues with the URLs.
This message was posted before February 2018.
After February 2018, "External links modified" talk page sections are no longer generated or monitored by InternetArchiveBot. No special action is required regarding these talk page notices, other than
regular verification using the archive tool instructions below. Editors
have permission to delete these "External links modified" talk page sections if they want to de-clutter talk pages, but see the
RfC before doing mass systematic removals. This message is updated dynamically through the template {{
source check}}
(last update: 5 June 2024).
Cheers.— InternetArchiveBot ( Report bug) 09:20, 23 January 2018 (UTC)
I'm running short of (referenced) things to add to the article. Either I'm not looking hard enough or there isn't a lot else out there. It would be nice to write some more about evolution, but I can't find references that discuss it. It is probably a super-AGB star, although has also been considered as a low-mass supergiant. Its evolution is balanced between becoming an exotic type of white dwarf or an unusual type of supernova, but not many people are going on paper to discuss it. Lithopsian ( talk) 11:41, 24 May 2020 (UTC)
@ Lithopsian:, isn't Canopus on warm side not cool side of instability strip? Cas Liber ( talk · contribs) 21:16, 13 June 2020 (UTC)
Also - the bit about precession and it, Achernar and the south celestial pole need a rewrite and better/reliable sourcing. Anything else? Cas Liber ( talk · contribs) 21:44, 4 September 2020 (UTC) @ Lithopsian: - one thing that might be good is what exactly it is about the spectrum that tells us it's already been a RSG and is in a blue loop....(?) Cas Liber ( talk · contribs) 22:19, 4 September 2020 (UTC)
Also this paper already used (gives the high abs mag value in infobox). Helps explain (later outdated) view that it is 15000 times as luminous as the Sun. Cas Liber ( talk · contribs) 14:04, 5 September 2020 (UTC)
The Observation section of the article contains this paragraph (which I've already trimmed):
Is this interesting or not? I don't think this content is worthy of such a long paragraph, but what do others think? Attic Salt ( talk) 03:05, 30 May 2020 (UTC)
Thanks for asking me to join :-) My eye was caught by the sentence "Canopus pulsates slightly with a period of 6.9 d. " I have not been able to find any papers to confirm this. Those old radial velocity variation from 1906 are probably not worth mentioning. By the way, RV variations can have other causes so if you do keep the reference, I would replace "pulsates" by "varies". Timb66 ( talk) 07:00, 15 June 2020 (UTC)
Actually the whole name bit needs an overhaul. R.H.Allen was not a terrific researcher but is all we have on lots of stuff. The section needs rejigging chronologically but I wish we could find better sources. Hence I found this which talks of Eudoxus of Cnidus going to observe it but not naming it (see p. 88). Cas Liber ( talk · contribs) 10:49, 7 September 2020 (UTC)
First the paragraph says From the imperial capital Chang'an, the star made a low transit across the southern sky, indicating true south to observers, and was often obscured by clouds. Then just one sentence later, it says ...it cannot be seen from the Chinese capital of Chang'an. Which is it?! According to the lat/long listed for the current incarnation of the city, it's at 34°15′54″N 108°57′14″E. Earlier in the article, and discussed here in Talk above, it's stated in theory the northern limit of visibility is latitude 37° 18′N with some variations due to altitude. Does anybody know a Chinese astronomer who can clarify this, please?
Corgi ( talk) 23:30, 17 December 2022 (UTC)
This paper refers to Canopus as the closest supergiant (yellow supergiant) to the Solar System, although it still cites the A9II classification. It gives it a mass of 9.81 M☉, consistent with that of a super-AGB star (as Lithopsian suggested above) and the progenitors of electron-capture supernovae (the accepted supernova lower limit is around 8.5 M☉, although this is not well defined). I've heard Kaler (who suggested a white dwarf fate for Canopus) isn't that reliable compared to other sources. Also, how come Canopus is just a bright giant (II) at 10,700 L☉ when Iota Carinae has a spectral class of A9Ib and 4,900 L☉? Stanley Joseph "Stan" ( talk) 00:58, 28 March 2024 (UTC)