Talk:IK Pegasi

IK Pegasi is a featured article; it (or a previous version of it) has been identified as one of the best articles produced by the Wikipedia community. Even so, if you can update or improve it, please do so.

This article appeared on Wikipedia's Main Page as Today's featured article on October 17, 2008.

Article milestones
Date	Process	Result
May 19, 2007	Peer review	Reviewed
June 9, 2007	Good article nominee	Listed
June 19, 2007	Featured article candidate	Promoted

Current status: Featured article

Review[edit]

I fixed some problems in the article. However some issues remain: 1) the formulae in the notes section are IMO unnecessary; 2) detailed discussion of parallax (including image) should be left for an appropriate article (parallax); 3) the value of metallicity lacks a source and ref [2] provide different information; 4)if B component has a O-Ne core (as written in the section 'Component B'), it can not be a Ia type SN progenerator; 5) instead of A-type it is better to write A-class (since it refers to a spectral class) 6) it is necessary to find better sources for stellar evolution. Ruslik 10:25, 7 June 2007 (UTC)[reply]

(1) The formulae were in lieu of a suitable reference, which was unavailable in those instances. (Otherwise they'd get tagged with {{Fact}} templates and need to be clarified.) So I believe them necessary, and other article pages use formulae for the same reason.; (2) Sentence is needed per Wikipedia:Explain jargon. Image removed; (3) footnote [2], p. 1050, table 2 gives an adopted value of [M/H]=+0.07±0.20; (4) Done; (5) Done; (6) Done (or else further clarification of requirement is needed). Thanks for the review. — RJH (talk) 16:35, 7 June 2007 (UTC)[reply]

In (1) I wrote IMO so I won't insist, but I fixed some technical problems with formulas and now they look better (3) It is better to use ref [5] for metallicity and [2] for pulsations (in the lead section) (6) Thermal pusles in AGB stars arise because nuclear burning alternates between hydrogen and helium i.e. helium flashes extinguish hydrogen burning shell and when helium ends hygrogen starts to burn again. Such alternations result in an extreme instability. The current sentence is imprecise in this respect. Ruslik 07:54, 8 June 2007 (UTC)[reply]
- Thank you for the clarification. For (3) the paper in ref. [5] just adopts the [M/H] values from ref. [2]. Would it be better to just cite both? For (6) I rewrote the paragraph with another reference and left the details of the pulsations unspecified. — RJH (talk) 15:12, 8 June 2007 (UTC)[reply]
  - I think it is possible to cite both sources. I made few minor fixes myself (use of tenses) and passed the article. Ruslik 11:49, 9 June 2007 (UTC)[reply]
    - Thank you. — RJH (talk) 18:01, 9 June 2007 (UTC)[reply]

REFERENCES - the reference No.1 appears to be published June 10, 2007 but retrieved on 2006-05-24, which is one year earlier.

Is there any typing mistake in one of the dates? --Franco3450 (talk) 16:06, 29 December 2008 (UTC)[reply]

Problem[edit]

The article states : In fact progenitor for this star is estimated to have contained as much as 5 solar masses.. However, when reading the reference (P282), it sounds that the progenitor mass was at least 5 solar masses (between 5 and 8 solar masses). There may be a mistake in the article. Poppypetty 18:47, 16 August 2007 (UTC)[reply]

The problem has been fixed. Spacepotato 22:09, 16 August 2007 (UTC)[reply]

Thanks. — RJH (talk) 22:41, 16 August 2007 (UTC)[reply]

I agree, Sirius B progenitor star was 9 solar masses, therefore it is quite likely progenitor star might have been as large as 12 solar masses. Betelgeuse when it goes supernova will also leave a remnant white dwarf near 1.2 - 1.25 solar mass.

Also OK Pegasi A has at least 100 million years left before it goes giant stage, someone should put a note as many might think this star might go nova very soon and kill all life on Earth. —Preceding unsigned comment added by 46.64.64.36 (talk) 02:17, 14 April 2011 (UTC)[reply]

Page Vandalism[edit]

Fixed page due to vandalism (see previous version detailed below.) —Preceding unsigned comment added by The Eagle1989 (talk • contribs) 07:49, 17 October 2008 (UTC) The Eagle1989 (talk) 07:53, 17 October 2008 (UTC)[reply]

[as edited by 217.65.238.154 (Talk) at 07:43, 17 October 2008.]

You might have a look at section 2.1 of http://relativity.livingreviews.org/Articles/lrr-2003-2/, per the citation.—RJH (talk) 01:14, 18 October 2008 (UTC)[reply]

B radius[edit]

Are you sure about the white dwarf radius being 0.6% of the Earth's radius (ie. <40 km)? The original source says 0.006 * R(sun) which yields around 4200km or about 60% of the Earth's radius, and more in line with the following statement: "...a mass greater than the Sun into a volume roughly the size of the Earth". (I would normally be bold here but this is on the front page and I could be wrong :-)) Astronaut (talk) 21:16, 17 October 2008 (UTC)[reply]

I'm not sure you read it correctly, or perhaps there was some temporary vandalism. It says 0.6% of the Sun's radius.—RJH (talk) 01:10, 18 October 2008 (UTC)[reply]

Seems User:Spacepotato changed it 5 mins after I left this comment. Thanks. Astronaut (talk) 15:30, 18 October 2008 (UTC)[reply]

It was correct prior to the front page exposure, so looks like it was the usual vandalism then. Thanks.—RJH (talk) 15:34, 18 October 2008 (UTC)[reply]

Contradiction on Chandrasekhar limit[edit]

This article reports there's a Chandrasekhar limit of 1.44 solar masses, but the article on electron degeneracy pressure limits itself to 1.38 solar masses. Which is correct? —Preceding unsigned comment added by 81.155.236.153 (talk) 22:40, 17 October 2008 (UTC)[reply]

The value varies, as mentioned on the Chandrasekhar limit article. Unfortunately, the electron degeneracy pressure article is not properly cited.—RJH (talk) 01:07, 18 October 2008 (UTC)[reply]

Neutron star[edit]

I don't know for sure, but I never heard of a "collapsing white dwarf" forming a neutron star. I understand that neutron stars are formed by Type II, Type I-b and Type I-c supernovas, which are the result of the collapse of a massive star, not a white dwarf. White dwarfs can form novae, or Type 1-a supernovae, but neither of these involve collapse. In a Type 1-a supernova, the white dwarf star is destroyed, it doesn't collapse.—Preceding unsigned comment added by Franco3450 (talk • contribs)

You might find the following paper useful:

Canal, R. (1997). "The possible white dwarf-neutron star connection". Astrophysics and Space Science Library. 214: 49. Retrieved 2007-02-01. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

Thanks.—RJH (talk) 17:53, 29 December 2008 (UTC)[reply]

References[edit]

I have already typed this note, but it was probably not perceived. Ref No.1 appears to have been published June 10, 2007 but retrieved on 2006-05-24, which is one year earlier than publishing date. Is there any typing mistake in one of the two dates?--Franco3450 (talk) 20:32, 2 January 2009 (UTC)[reply]

Yes, it was likely a copy-paste error. I updated the citation to fix the date and use the new URL. Thank you for pointing it out.—RJH (talk) 21:04, 2 January 2009 (UTC)[reply]

Change of Distance with time[edit]

In the Future Evolution section of the article there is a calculation suggesting that the star will be over 500 lyrs away from the sun in 5 mill yrs. This is based on the space velocity of 20.4 km/s. I am not 100% sure but I would have expected that the calc should be based on the radial velocity, 11.4 km/s, which I believe to be the true indicator of the change in distance to the star. If I am correct only the numbers would change as the conclusion of the paragraph is not affected. 212.2.2.5 (talk) 12:50, 8 May 2009 (UTC)DS[reply]

As the system moves transversely to the line of sight, the radial velocity will change. Hence, you need to take into account all components of the motion.—RJH (talk) 17:04, 14 April 2011 (UTC)[reply]

Image[edit]

It's kind of amusing to find that an illustration I made for this page is showing up on a Universe Today web page and is being credited to NASA. I guess what comes around goes around, eh? ;-) Regards, RJH (talk) 22:31, 19 December 2011 (UTC)[reply]

External links modified[edit]

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Timescale for the supernova explosion[edit]

The doomsday circuits have now picked it up (probably from "IK Pegasi B is the nearest known supernova progenitor candidate."), but anyone coming for information here to dispel them will not find much.

Despite being featured, the article is too vague on the timescales. From the article:

"in the time it will take for the system to evolve to a state where a supernova could occur"

"It is thought that the primary star, IK Pegasi A, is unlikely to evolve into a red giant in the immediate future."

What is "the immediate future"? It must be possible come up with an order of magnitude estimate or a lower limit. Presumably it is at least tens of millions of years. First IK Pegasi A must evolve and the accretion by IK Pegasi B also takes time.

--Mortense (talk) 19:04, 8 February 2023 (UTC)[reply]

I updated the statement based on a source. Praemonitus (talk) 22:21, 8 February 2023 (UTC)[reply]