Talk:Polaris

--67.133.79.98 14:46, 27 October 2006 (UTC)The figure for the semimajor axis of the companion, given as 5 AU, is obviously in error. Here's why: a = cuberoot of the total mass times the period squared (say, 30 years). For any reasonable value of M (which can hardly be less than 10 times our sun's, given the luminosity of Polaris A), the size of the orbit comes out at about the distance of Pluto from the sun--not Jupiter!--for having extra mass in the system, causes them to revolve FASTER.[reply]

Addendum. When i wrote the foregoing, i didn't have precise figures for Polaris's mass. By the Cepheid relation M = .58 + .24 log P (in days) the mass of the primary should be about 5.29 times the Sun (not 8 to 10, which is more typical of a F-type supergiant of this luminosity). Assuming for the moment that the unseen companion is about 300 times dimmer than the visible primary, this comes out to a mass ratio of about Ma/Ma+Mb of 0.75; & the semimajor axis is 18.35 Astronomical Units (or 18.7, if you use Burnham's period of 30.5 years)...more like the distance of Neptune. (Its eccentricity takes the two stars from 7 to 29 AU separation.) The displacement of the primary amounts to about 4.58 AU, or 426 million miles, presumably the source of the quoted figures (with 290 million miles, given by Burnham, the mass of the companion becomes very small indeed). But this is a small portion of the entire orbit.

This is a good subject for calculating derived figures on, for the values derived from Cepheid equations can be tallied with the observed type F3 main sequence third star; thus the range of distances possible is fairly narrow, in comparison with many other supergiant stars, e.g. Canopus or Rigel.

Exterior Cosmology

Is is known yet whether the Earth rotates in a Galactic or Exterior Object cosmology? That can be boiled down to whether the Earth's axis is stable in relation to the Milky Way Galaxy or to the exterior galaxies such as Andromeda and the zillions of others.

SyntheticET (talk) 17:45, 17 November 2007 (UTC)[reply]

Dominance of the North?

I once read that a major factor contributing to the dominance of the northern hemisphere in such activities as ocean navigation and widespread colonization and travel was due to the fact that there is a North Star, but no South Star. Has anyone else heard this? --Golbez 21:31, Sep 27, 2004 (UTC)

Nope I haven't seen that one, but see also Guns, Germs, and Steel. — RJH 20:01, 17 January 2006 (UTC)[reply]

I could figure out the point in the sky thats south based on the constellations in one night of looking up there. Ancient people have figured out things a lot more complicated than that.

It is definitely nothing to do with the pole star - it's quite simple there is far more land and resources in the Northern hemisphere and so there have always been far more people in the Northern hemisphere. In any case, around the time of Christ there was no bright star within 5° of the pole whereas Miaplacidus was quite close to the South pole --AssegaiAli 18:05, 9 October 2007 (UTC)[reply]

Join this article?

This article is of the same subject as North star, and Pole star. i think it would be good to join these articles.

above by 12:54, user:Gxojo at 12:54, 28 Jan 2005

No, North Star is not about Alpha Ursae Minoris per se. It is about all North Stars, such as will be Vega in the future. And pole star covers both North Star and South Star (or should). Polaris, inappropriately named, covers only Alpha Ursae Minoris. 132.205.15.43 04:00, 1 Feb 2005 (UTC)

Visibility from the Southern Hemisphere

Polaris can be visible from locations near the equator in the southern hemisphere. Polaris is about 0.75° from true north. At an elevation of 3km, horizon dip is 1.75°, and atmospheric refraction can be good for another 0.5°, depending on conditions. Adding these up, Polaris can rise over the horizon at locations as far as 3°S.

At 3km elevation, atmospheric extinction at 3° from the horizon can be as low as 2 magnitudes, and as low as 5 magnitudes at the horizon itself. Under these near perfect circumstances, Polaris could be a naked eye magnitude 4 at (or just south of) the equator, and up to magnitude 7 at 3°S.

Distance from the north pole

Shouldn't it be 42', not 42" ? Or what exactly does " mean (compare the coordinates)? Otoomet 16:45, 2 July 2006 (UTC)[reply]

Oops, that's embarrassing. I actually wrongified that part of the article months ago. The HTML should have read ′ instead of ″. I've fixed it. -- Xerxes 20:58, 2 July 2006 (UTC)[reply]

Polaris Ab

This 10 Jan 2006 news release contained material an amateur like me would be interested to read in the article:

"The companion proved to be less than two-tenths of an arcsecond from Polaris — an incredibly tiny angle equivalent to the apparent diameter of a quarter located 19 miles away."
By watching the companion star in its 30-year orbit, astronomers expect to learn not only the stars' orbits but also their masses, valuable because it is the nearest Cepheid variable, the brightness variations of which are used to measure the distances of galaxies and the expansion rate of the universe.

--Wetman 06:10, 18 October 2006 (UTC)[reply]

General complaints

"Rust in Peace...Polaris". Is a reference to the nuclear missile system, and nothing to do with the star apart from the missile system beign named after it, which is just daft.

From the linked article on the album:-

"I was driving home from Elsanon... um, Lake Elsanon. I was tailgating somebody, racing down the freeway, and I saw this bumper
 sticker on their car and it said... you know, this tongue in cheek stuff like, 'One nuclear bomb could ruin your whole day,' and
 then I looked on the other side and it said, 'May all your nuclear weapons rust in peace,' and I'm goin', ' 'Rust in Peace.' Damn,
 that's a good title.' And I'm thinkin' like, 'What do they mean, rust in peace?' I could just see it now - all these warheads
 sittin' there, stockpiled somewhere like Seal Beach, you know, all covered with rust 'n' stuff with kids out there spray-painting
 the stuff, you know." - Dave Mustaine, the band's main songwriter.

Obviously and from the horses mouth, nothing to do with the star. Perhaps the song should be linked in an article about bumper stickers?

As for "In the song, Polaris is the name of a disease." lyrics from the song:-
    "I am a nuclear murderer I am Polaris
     Ready to pounce at the touch of a button"

"Load Star" Load of BS. It was Lode only, until the bloody educational collapse of the late 20th century meant that no-one can spell anything anymore. Lodestone points to the lode star, a load of stone just sits there.

While I'm on it, the diameter of quarters is only a useful example to people in the US who regularly see quarters. 195.27.13.34 13:13, 8 June 2007 (UTC)[reply]

Star chart for North Pole

I suggest it would be useful to draw a diagram of the stars near celesial north pole, and trace a rough path of the pole over time. --206.75.168.235 05:15, 2 August 2007 (UTC) :( Actually, I'm Kevinkor2 (talk · contribs) but too lazy to log in. ):[reply]

Culture section

Does a list of bands really belong in an encyclopedia article about an astronomical object? Keeping in mind that Wikipedia is not a trivia collection, are there any reasons to keep it? Feezo (Talk) 19:08, 19 August 2007 (UTC)[reply]