Talk:Tau Ceti/Archive 1

Luminosity
I believe the figure given for the luminosity of Tau Ceti (0.62 Solar Luminosities) is incorrect, based on other information that is given in Wikipedia and elsewhere on the Web.

The absolute visual magnitude of Tau Ceti is given as 5.68, and the sun's absolute visual magnitude is 4.77. The difference is 0.91, which means the Sun is almost a full magnitude brighter than Tau Ceti, or about 2.312 times (five standard magnitudes = 100 times brighter, one magnitude = 100^0.2, or about 2.512). The figure for luminosity can be calculated when you do the following calculation:

1 / 100^(0.2*0.91) = 1 / 100^0.182 = 0.432.

I have not yet corrected the luminosity figure in the entry because I wish to check my calculations and confirm the results from other sources on the Web and reference books. --B.d.mills 02:34, 19 Oct 2004 (UTC)

UPDATE: I have checked the calculations and they are correct. I have updated the absolute magnitude of Tau Ceti to 0.43.--B.d.mills 23:54, 19 Oct 2004 (UTC)

In fiction - Complaints Department of Sirius Cybernetics Corporation
The Hitchhiker's Guide to the Galaxy mentions the Complaints Department of Sirius Cybernetics Corporation to be in Sirius Tau in some versions, and in Sirius Tau Ceti in some other versions. Would that be the same Tau Ceti that this article is about? --(boxed) 00:19, 4 December 2005 (UTC)

Very likely. It would mean that the Sirius Corporation has settled, or artificially created, a planet in orbit around Tau Ceti and named it after itself. One more world for the already crowded Tau Ceti System. I hope somebody creates a "Rainbow Tau Ceti" in which all of these worlds, over a dozen of them, are real - similar to Larry Niven's Rainbow Mars, in which the various Martian races and cultures created by great Science Fiction writers - Bradbury, Burroughs, Lewis, Wells, etc. - are all real and competing with each other. Das Baz 16:38, 12 August 2006 (UTC)

Expansion
The introduction paragraph describes the metallicity of the star and rest of the article is about the debris disk. This star deserves much more.--JyriL talk 16:57, 12 August 2006 (UTC)
 * Content has been significantly expanded. &mdash; RJH (talk) 21:30, 15 November 2006 (UTC)

Artificial Worlds
The asteroidal and cometary material can be used to create artificial planets and habitats for human settlement. Das Baz 18:10, 2 September 2006 (UTC)

Durre Menthor
The following text was removed from the main article because I could not find a valid reference to confirm this assertion:
 * However, Tau Ceti once had the now obsolete name of Durre Menthor, derived from the Arabic درر منثور Al Durr' al-Manthur, meaning "Scattered Pearls".

It was inserted into the article by an anonymous user with no talk page. I'm adding it here in the hopes that a reference can be found in the future. Thanks. &mdash; RJH (talk) 19:54, 16 November 2006 (UTC)
 * Possibly here: DavidMalin.com: Durre Menthor, a blacklisted source said from: Al Durr al Manthur, translation not found, yet. The name seems to be a real one, not a hoax. ... said: Rursus (bork²) 15:18, 24 June 2009 (UTC)
 * Now, let's test another site: Omnipelagos.com: Cetus: &lt; الدرر المنثور al durr' al-manthūur The Scattered Pearls (of the Broken Necklace). ... said: Rursus (bork²) 15:22, 24 June 2009 (UTC)
 * There might be a small issue with the reliability of those sources, per Reliable sources. It would be good if we had something more authoritative, but I couldn't find any book or journal (in English) to corroborate that name.&mdash;RJH (talk) 18:44, 24 June 2009 (UTC)

Good Article
This article appears to meet all of the criteria for a Good Article. The prose could be cleaned up further, and a more photographic image would be a nice addition, but the article is pretty extensive and well-referenced. (Additional references in the "Observations" section would also not be amiss, unless that entire section is drawn from the single source cited.) Congratulations, and thanks for your hard work. Shimeru 22:46, 11 December 2006 (UTC)


 * Thank you. I've added in some more references to the Observations section. Unfortunately I'm not sure where I can get a good photograph at present. At best it would be a bright splotch on a dark background. (Maybe some day when there's better telescopes...) Hopefully some kind visitors will work on polishing the prose a little more; it's sometimes difficult to find such issues with one's own contributions. &mdash; RJH (talk) 22:52, 11 December 2006 (UTC)
 * (Me too vote). I think this looks good too. Good work! --Ling.Nut 22:55, 11 December 2006 (UTC)
 * I know that all too well. I realize the technical limitations on actual photographs, too, but I still think it would add something to the article.  Maybe it's just me.  It's not exactly a major issue, in any case. Shimeru 23:48, 11 December 2006 (UTC)
 * Okay I added an illustration. &mdash; RJH (talk) 16:23, 5 January 2007 (UTC)

Temperature, Rotation and Duskdisk...
In the first : sorry for my weak english. I came to this article, because the german article to "tau ceti" is very empty. I'm very interested about tau ceti, because i write a story, that based on this star. So i search a lot of material about this star. And so i recognize, that the temperature, that is given here, is not a "true temperature" - it's only based on a equation of black-body-temperature, at a same emission of energy, given by a real measured radius of a body (in this case: star). But no Star is a perfect black-body - so the calculated temperature by a black-body-equation only can be a nearing to the real temperature. And then, there is a caution given by the luminisity through the whole spektrum of radiation, to the visual spektrum. Thats the reason, why there exists : bolometric (whole spektrum of radiation) magnitude (Mbol), and visual magnitude (Mv). The black-body-equation means whole spektrum - but it still be a nearing to the real temperature, and not the exact temperature of the star.In the references there are published measurements of the american astronomical society (through 1984 to 1992), and they came to a temperature : 5528.9 K plus-minus 1.1 K), (http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?letter=.&classic=YES&bibcode=1994ApJ...427.1042G&page=&type=SCREEN_VIEW&data_type=PDF_LOW&send=GET&filetype=.pdf) - on Site 1043 - if i'm understand the publishing in the right way. I also read for the rotation-time 31 days, in other sources.I think the way, to measure the rotation, was the same, like it the way it stands in the link i'm given here. So the reason for the differences are only in a error-range ? In this case, it would be better to write in the wikipedia-article : "rotation: 31 - 34 day's" - or not ? Then: the duskdisk. I wonder how they measured the distance to tauceti. Are they counted the pixels from the picture each for each ? I hope not. Because the angle from which we see to the tau-ceti-system is unknowned (by the measurements about the activities from tau ceti (and for sure his rotation too) the scientists only can "thinking" that we are look to the bottom or top, of the tau-ceti-system (because the results are speaking for a "to little" rotation-velocity). The mesurements give a temperature of the duskdisk about 210 K. I would approximate the albedo of body's like those in the kuiper-belt, and asteroid-belt, and then calculate the distance, in which those objects has 210 K, at a star-radiation which tau ceti has - to came to a distance-value. This value can be compare with the image of the dusk-cloud (seen here : http://www.solstation.com/stars/tau-ceti.htm > http://www.solstation.com/stars/tau3ceti.jpg) - and also could compared for a reconstruction of the angle, from which we are look to tau-ceti (because the dusk-belt, is always in a angle near 90 degrees to the rotationaxis of a star, i think (for sure, when there's not a 2-star-system)). The age of tau ceti is also not sure (like they seems to given in this article) - the measurements only allows a result between 4 billion and 10 billion years. I think, this would good to correct in the article to "4 billion to 10 billion years" - because : on the base of which measurement can explain an exact result of 10 billion years ? All measurements have a error-range, and i think, this would be good to taking in the article - for a higher sensibility of scientific caution in "publishing of facts". Lots of Greets from Austria, Pygmalion1 (24. February 9:27 CET)
 * Hi Pygmalion1. I think I understand most of what you're asking. In most cases I think it's usually better to go with the most recent estimates.
 * Yes the Teff is at an appropriate level in the photosphere. I updated the Teff to 5,344 K based on a 2004 paper in A&A. This was, in turn, based on Santos et al [2004, A&A, 415, 1153]. The listed error range is about &plusmn;50. Rammacher and Cuntz [2003, ApJ, 594:L51-54] give Teff = 5,320 &plusmn; 70 K. Ecuvillon [2004, A&A, 418:703-715] gives 5344 &plusmn; 29 K.
 * For the rotation rate, Sarra and Olsen [1996, MNRAS] give 34.5 days. Baliunas, Sokoloff, & Soon [1996, ApJ] give 34 days. I couldn't find a more recent estimate, but Rammacher and Cuntz [2003, ApJ, 594:L51] use the 1996 Baliunas, Sokoloff, & Soon estimate.
 * Yes the 10 Gyr age in the infobox is a best estimate; the actual modelled range is described in the text. I added a tilde to indicate it's an approximation; the estimated age is from the referenced paper by Folco et al.
 * The distance to Tau Ceti was measured via parallax; particularly based on the Hipparcos results. The reference is the SIMBAD data page.
 * The location of the dusty disk, I believe, is based on the radiation output from the star and a model of absorbtion and infrared radiation from the dust. This is described in the text.
 * Thanks. &mdash; RJH (talk) 17:11, 26 February 2007 (UTC)

Thank you for your answer - but the fourth point would'nt nescessary - because : i'm NOT meaning the distance from earth to tau ceti - i mean the distance of the dusk-cloud to tau ceti. In the 5th point you gave me a answer to this question, and in the other points to the other questions. I'm pleased :-) - Thank you. Greetings from Austria, Pygmalion1 (2. March 2007, 19:46 CET)
 * Good. I thought your meaning might not have translated accurately, so I gave both answers. Glad to help. &mdash; RJH (talk) 19:00, 4 March 2007 (UTC)

for later
http://caao.as.arizona.edu/publications/woolf1998_astronomical.pdf —Preceding unsigned comment added by Marskell (talk • contribs) 23:13, 21 September 2007 (UTC)

Unsourced assertion
The following was inserted into the text without a reference:
 * Advanced age is also suggested by a lack of variability.

I think it's correct, but the page is in the middle of an FAC so a proper reference would be appreciated. Thanks. &mdash; RJH (talk) 14:50, 1 October 2007 (UTC)

Solar analog
Hello,

I think it would be interesting to add a reference to the fact that Tau Ceti is a solar-analog. Thanks in advance. Poppy 10:48, 3 November 2007 (UTC)
 * I don't have access to the original paper, Stars resembling the Sun, but the "Hipparcos Results for Solar Analogs" postscript page (accessed from google) does not list Tau Ceti as a solar-analog star. So it may be considered more solar-like. The Chromospheric Activity and Variability of Cycling and Flat Activity Solar-Analog Stars lists Solar-analog stars as having $$\begin{smallmatrix}0.58 \le B - V \le 0.72\end{smallmatrix}$$, which would thus barely include Tau Ceti. So I think it's borderline, but the lack of variability probably weighs in its favor. &mdash; RJH (talk) 18:12, 3 November 2007 (UTC)

Neighbourhood
Tau Ceti is a "southern sky" star in the constellation Cetus ("the whale"); assuming perfect viewing conditions, it is visible below latitude 75°N. The constellation is large and lies just south of the celestial equator. Notable stars include the highly variable Mira. Although in the same general direction as seen from Earth, stars in a constellation may not be especially close to one another. For instance, the orange giant Beta Ceti, the brightest star in Cetus, is nearly one hundred light years from Sol, compared to Tau Ceti's twelve. As with the Sun, most of Tau Ceti's neighbours are faint M dwarfs and are not visible with the naked eye. YZ Ceti and Luyten 726-8 are the two closest known stars to Tau Ceti.

I have a number of concerns about this section:


 * "The constellation is large..." lacks precision. How large is it and compared to what? It should say something like it is the Xth largest constellation, then give a reference.
 * "...and lies just south of the celestial equator" is redundant with the first sentence.
 * "Notable stars include the highly variable Mira." This material belongs on the Cetus page. This article isn't about the constellation.
 * "As with the Sun, most of Tau Ceti's neighbours are faint M dwarfs and are not visible with the naked eye." Where's the reference?
 * The image provided looks like a black box on my screen. The contents are essentially invisible.

I think the section needs significant re-work for it to be included in a featured article. Sorry.&mdash;RJH (talk) 17:09, 9 March 2008 (UTC)

Trying to rework it:

The constellation Cetus ("the whale") is located just south of the celestial equator, making Tau Ceti a "southern sky" star; assuming perfect viewing conditions, it is visible below latitude 75°N. Although the other stars in Cetus appear in close proximity to Tau Ceti, many are located at much greater distances. For example, Beta Ceti, the brightest star in Cetus, is nearly one hundred light years from the Sun, compared to Tau Ceti's twelve. YZ Ceti and Luyten 726-8 are the two closest known stars to Tau Ceti.

debris dis[ck]
I'm not so familar with english, but in the text "debris disc" and "debris disk" are mixed up. --FrancescoA (talk) 09:17, 3 April 2008 (UTC)


 * Fixed. Thank you.&mdash;RJH (talk) 21:56, 3 April 2008 (UTC)

pronunciation
[siːtaɪ]? Every time I've heard this star's name, or anything else in this constellation, I've heard it pronounced [sɛtiː], rhyming with "jetty". Is there any source for it being [siːtaɪ]? I know scientists generally don't seem to follow the pronounciation rules observed in classical latin, but since the genitive of Cetus would be pronounced [keti], I struggle to believe that all astronomers insist on pronouncing three out of four letters completely differently. - file lake  shoe  21:06, 12 April 2009 (UTC)
 * I have no idea where the pronunciation was obtained. To me the pronunciation entries belong in the wiktionary. Feel free to tag it with a Fact template and we can remove the entry later if it does not get addressed. Thanks.&mdash;RJH (talk) 23:38, 12 April 2009 (UTC)
 * Hm, well a bit of searching has actually suggested [siːtaɪ] is the "accepted" pronunciation at least. Found an interesting well sourced article on pronunciations of constellations here, which explains why they're not pronounced like latin words. - file lake  shoe  00:35, 13 April 2009 (UTC)


 * I wonder if the "settee" pronunciation could be interference from SETI. It's not pronounced as in Latin because we're not speaking Latin. kwami (talk) 01:06, 13 April 2009 (UTC)