Talk:Beta Centauri

Nighttime sky?

The opening reads:

"Beta Centauri (β Cen / β Centauri), also known as Hadar or Agena, is the second brightest star in the constellation Centaurus and the tenth brightest star in the nighttime sky."

I'm contemplating a grammatical correction. The term "nighttime sky" might read better as "night sky":

"Beta Centauri (β Cen / β Centauri), also known as Hadar or Agena, is the second brightest star in the constellation Centaurus and the tenth brightest star in the night sky." Ricardo10 18:52, 25 August 2007 (UTC)

Dubious distance

The distance given is dubious. The distance is given as 525 light years, however recent research suggests that the distance is more like 330 light years. The HIPPARCOS probe ran into systemic difficulties measuring the distance of this particular system. The two bright components have an orbital period of about 350 days, and when this was superimposed on the 365-day parallax cycle it skewed the results. The following references discuss this in more detail.

References

• http://kencroswell.com/BetaCentauri.html (352 +/- 13 light years)
• http://www.ingentaconnect.com/content/bsc/mnr/2005/00000356/00000004/art00014 (102.3 +/- 1.7 pc [333.7 +/- 5.5 ly])

-- B.D.Mills  (T, C) 05:20, 1 March 2008 (UTC)

I've been bold and edited to reflect the changes as well as the higher mass estimates (A,B) both being about 10 solar masses. Will change the remainder of the figures to reflect the new distance and mass estimates.Benkenobi18 (talk) 06:57, 2 January 2009 (UTC)

Confusing description and contradictions.

The description of this star system is rather confusing and redundant. In one paragraph it states that Hadar is a triple star and then in the following paragraph it repeats that as if the previous paragraph didn't exist. In the same paragraph it says that each member of the close binary pair weighs 9.1 solar masses and then in the following paragraph it says they weigh 10-11 solar masses. Which paragraph is correct? Also there are 2 contradictory orbital periods. One is 352 days while the other is 357 days. Again, which is correct? I'm going to try to correct the errors and improve the readability of this article. Dr. Morbius (talk) 00:18, 1 May 2010 (UTC)

Source of Name?

The article refers to the name Hadar being of Arabic origin, meaning "ground." I'm curious as to the source for this. It seems to me that a more reasonable source would be Hebrew, in which case the translation would be "glory", a more fitting explanation for a relatively bright star. Khommel (talk) 20:55, 18 June 2010 (UTC)

Copyvio

It appears that material introduced during this sequence of edits was copied almost word for word from Professor Jim Kaler's article on Beta Centauri. I've attempted to extract the inappropriate content per WP:COPYVIO. Regards, RJH (talk) 18:48, 19 December 2011 (UTC)

Disambiguation doesn't

"This article is about β Centauri and should not to be confused with Alpha Centauri B. For B Centauri, see B Centauri. For b Centauri, see HD 129116." Who's on first?

Orbit of Beta Centauri B

The article as of August 30, 2016 says "Beta Centauri B orbits the primary at 0.6 light years, or 100k AUs, with a period of roughly 1500 years." this is inconsistent with the box which says the period is 288.267 yr and the distance seems highly implausible. This web page says "Hadar B orbits the close pair at a minimum distance of 120 Astronomical Units (AU), taking at least 225 years to make the trip." which seems more likely. However, I have not been able to find a primary reference. Pmokeefe (talk) 09:50, 30 August 2016 (UTC)

Hi @Pmokeefe:, Kaler is a professor of astronomy so it is likely a good source. Still it'd be good to find the jounrnal I agree...Cas Liber (talk · contribs) 11:25, 30 August 2016 (UTC)

Kaler is a professor of astronomy, but he has a habit of making stuff up on the hoof (particularly names). Usually very credible, often a bit out of date, occasionally just "imaginative". One of the few blogs that might be a reliable reference for Wikipedia, better to refer to his book which is at least in print, but I always try to find a peer-reviewed source so people can see where the claims really came from. Lithopsian (talk) 15:47, 30 August 2016 (UTC)

The separation of 0.87" is from the Hipparcos catalog. The pair have been measured as recently as 2012/13 at a separation of 0.4". The period given in the MSC (in cases without a calculated orbit) is a guesstimate calculated from the apparent separation, parallax, and assumed mass sum. Obviously this varies with the changing apparent separation., but comes to 288 years for a separation of 0.87" Lithopsian (talk) 15:47, 30 August 2016 (UTC)

I found a more recent paper discussing Beta Cen and it states a probable orbital period between A and B of 125–220 yr, the uncertainty seems largely due to the current lack of constraint on eccentricity. This is clearly inconsistent with the claim in the article which lacks citation so I've removed it.

Massive pulsating stars observed by BRITE-Constellation I. The triple system β Centauri (Agena)

ChiZeroOne (talk) 10:32, 24 May 2018 (UTC)

References

Not Eleventh brightest?

Isn't it slightly lower in brightness than Betelgeuse? It is according to the list of brightest stars on wiki.77.100.156.159 (talk) 21:38, 2 October 2016 (UTC)

The list can change order from time to time. Betelgeuse in particular is variable, so trying to impose a rigid order on the brightness of stars is pointless. I re-worded it to a generally-true statement. Lithopsian (talk) 19:08, 3 October 2016 (UTC)

"Asterism"

Second paragraph referred to the Southern Cross as an "asterism". But asterism is defined here on Wikipedia as a group of stars NOT recognized as a constellation by the IAU, and the list of constellations officially recognized by IAU does include Crux (Southern Cross). Accordingly I will update article. 69.140.25.127 (talk) 16:39, 7 March 2020 (UTC)

Be careful, Wikipedia is not a reliable source. Lithopsian (talk) 15:16, 24 September 2020 (UTC)

Inconsistency in masses from text to table

The masses of the stars mentioned in the text and the tables seem to be incompatible. For example the text mentions "Aa is 12.02 ± 0.13 times as massive as the Sun", while the table lists 10.7 ± 0.1 solar masses. For Ab there is a smaller inconsistency too. This should be fixed as either the text or table is wrong or outdated. — Preceding unsigned comment added by 2A02:1812:1401:2300:1AE:70DF:AC35:8B96 (talk) 15:08, 24 September 2020 (UTC)

I made some updates. Should be more consistent now. Lithopsian (talk) 16:22, 24 September 2020 (UTC)

That's not the only inconsistency. The article says that B is a dwarf, but the infobox says its mass is 4.61 solar masses. So this dwarf is almost five times as massive as our Sun? —MiguelMunoz (talk) 18:47, 21 March 2024 (UTC)

"Pointers"

The article now says that A and B Centauri can be used to find Gacrux (which in turn together with Acrux points south). Which is true I guess. But the pointer can be used more directly to find the South Pole: at the point where the axis of the southern cross (from Gacrux through Acrux) intersects an imaginary line passing in between A and B Centauri. See the diagram that is used in the "Pole star" article. Greetings, RagingR2 84.27.42.152 (talk) 22:57, 4 March 2021 (UTC)