Talk:Crab Nebula

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Former featured article Crab Nebula is a former featured article. Please see the links under Article milestones below for its original nomination page (for older articles, check the nomination archive) and why it was removed.
Main Page trophy This article appeared on Wikipedia's Main Page as Today's featured article on June 14, 2006.
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Date Process Result
May 21, 2006 Featured article candidate Promoted
March 17, 2015 Featured article review Demoted
Current status: Former featured article
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Version 0.5      (Rated B-Class)
Peer review This Natsci article has been selected for Version 0.5 and subsequent release versions of Wikipedia. It has been rated B-Class on the assessment scale.

Origins[edit]

SN 1054 was unquestionably the first astronomical object recognized as being connected to a supernova explosion. The statement refers to when the connection was claimed, not when the supernova occurs. Other systems such as SN 185 might have happened earlier, but they were not recognized as being possibly associated with a supernova remnant until quite recently. (And SN 185 is a bad example because it is a controversial association in any case.) Tubbs334 21:17, 27 May 2007 (UTC)

Dating[edit]

Is it possible to confirm the dating of SN 1054 by some other studies, not based on dates from Chinese chronicles? For example, a paper by R. Nugent, http://www.journals.uchicago.edu/PASP/journal/issues/v110n749/980055/980055.text.html - together with the sources cited there - suggests the year of 1130 ± 16, rather than 1054, based on linear expansion model. The obvious discrepancy is explained as the effect of the "well-known acceleration in the Crab's expansion", but no estimations are provided. FedorB 21:13, 20 June 2007 (UTC)

There is a possibility that is was recorded by irish monks in one of the numerous irish annals. I am a bit dubious as to the validity of the annal as it lists a star visible during the day for one day on april 24 1054, sometime before the Chinese accounts were made. And supernovae do not release a flash that would be required for both accounts to be reconciled. — Preceding unsigned comment added by 86.43.94.254 (talk) 12:12, 30 August 2011 (UTC)

Triple Composite NASA Image[edit]

Sig06-028.jpg

The Crab Nebula composite image using data acquired by the Chandra X-ray Observatory, Hubble Space Telescope and Spitzer Space Telescope released by NASA on 2006-10-25.

I've chosen the above image as a Portal:Astronomy picture of the week. Since I can't truthfully claim a neutral point of view with respect to this image, I post here to draw attention for consideration by future editors. – Conrad T. Pino (talk) 03:08, 10 June 2008 (UTC)

Distance[edit]

I think it is misleading to say that <<Tracing back its expansion consistently yields a date for the creation of the nebula several decades after 1054>>. Rather, the explosion of the supernova took place 6300 years before 1054 A.D., that is at roughly 5300 B.C. (provided that the distance between the supernova and the solar system did not appreciabely change during this time). 141.51.191.59 (talk) 11:30, 30 June 2008 (UTC)

  • It is common practice in astronomy to date an event by when it was observed from Earth, because distance, and thus how long the light took to reach us, can be very uncertain. --Etacar11 14:59, 30 June 2008 (UTC)

Image[edit]

Hello,

you may want to include this image in the article.

Position of Crab Pulsar in the Milky Way. Crédit : NASA/DOE/International LAT Team.

Poppy (talk) 23:58, 28 August 2008 (UTC)

A 3-D animated GIF may be helpful, like this one: http://www.flickr.com/photos/hindt3d/2141719273/ —Preceding unsigned comment added by 192.154.91.225 (talk) 20:17, 4 March 2010 (UTC)

Radius of the Nebula[edit]

The radius of the nebula reported in the right column once was "6.5 ± 1.5 ly" and contradicted the diameter of the nebula reported in the last sentence of the first paragraph "the nebula has a diameter of 11 ly (3.4 pc)" which gives a radius of 5.5 ly (1.7 pc). Hence, I changed the value in the right column to "5.5 ly (1.7 pc)". Determining the radius of an irregular nebula that isn't all that circular may be unscientific, but this value (5.5 ly) is cited in "An Introduction to Modern Astrophysics", Second Edition. By Bradley W. Carroll and Dale A. Ostlie, agrees with the 1st paragraph of this same article, and agrees much better with an extrapolation of the radius using its know expansion rate and the date it was observed (July 4th, 1054), including the accelerated expansion since the supernova.

Some Old Man (talk) 12:28, 30 April 2009 (UTC)

Arab astronomers[edit]

Per this Scientific American article, Arab astronomers did not actually record SN 1054, so I've removed the mentions to them in the "Origins" section. howcheng {chat} 00:36, 4 July 2011 (UTC)

Apparently they were added back. As the SN 1054 article makes clear, which is really the appropriate place to discuss this in any detail, SN 1054 was "recorded by Chinese astronomers in 1054". Mentions of Japanese or Islamic astronomers would be more tenuous. Apparently there is one record by an Islamic astronomer, who lived in the 13th century, and one by a Japanese astronomer, who also lived in the 13th century. So it may be argued (i.e., over at SN 1054) that the event did not go entirely unrecorded in both Japan and the Islamic world, but it would be wrong (or unsubstantiated) to say that it was "recorded by astronomers in 1054" in those places. --dab (𒁳) 20:31, 14 April 2013 (UTC)

3C number[edit]

Does this object have a 3C catalogue number. Other similar radio objects do, but this one seems to have it omitted? — Preceding unsigned comment added by 193.167.170.47 (talk) 19:11, 11 November 2013 (UTC)

Featured article review[edit]

I was disappointed while addressing a citation needed tag to discover that neither of the citations given in the paragraph on Herschel actually supported the content of the paragraph. One was a book review of an offline source and one was linked to a library catalog entry for an article that supported some details in the paragraph but not all of it. I have amended these two references so that they point directly to the sources rather than reviews or catalog entries of them. I think this article would benefit from a more in-depth source review and spot check and the addition of sources where they appear to be lacking. DrKiernan (talk) 15:18, 30 December 2014 (UTC)

Absolute magnitude[edit]

Does it make sense to quote a magnitude at 10 parsecs for an object that is over 3 parsecs across? Especially one calculated by the author of this article from dubious data? Who says the distance modulus is 11.5? Has this just been calculated from the distance? That isn't appropriate as a Crab suffers from non-trivial extinction. One old source I checked quickly gave a value of 1.6 magnitudes for the visual extinction. Lithopsian (talk) 22:18, 17 February 2015 (UTC)