As far as the science concerning the North Star, a triple star system, commonly called Alpha Ursae Minoris (α UMi), is the closest relatively bright star to the north celestial pole. It lies at an estimated distance between 323 and 433 light years (99 to 133 parsecs) from Earth and has an apparent magnitude that varies between 1.86 and 2.13 and Polaris is the closest Cepheid variable star to Earth. Polaris is around 4000 times brighter than our sun.
The North Star Polaris is not actually flickering. It is a bright trinary star system with a yellow giant (Aa) ~ 5 times more massive than our Sun, a yellow F6 (Ab) star ~ 1.26 Sols, and a third (B) class star ~ 1.39 Sols.
Aa is a cepheid variable star* which goes through cycles of months or years where its brightness increase and decreases, but this is not happening fast enough to appear as flashing.
Polaris sits above Earth’s north polar axis so it appears to be stationary in the sky in relation to our Earth’s rotation. If you take a multi-hour time elapsed photo of the night sky in the northern hemisphere, other stars will appear as curved lines, but Polaris will appear a stationary dot.
When Polaris appears to flash, it is most likely exhibiting fluctuating thermal distortions, or scintillations, in the atmosphere deflecting Polaris’s light to your eye. This is happening fast enough that it could appear that the star is flashing.
See:
https://www.britannica.com/place/Polaris-star
See:
https://www.quora.com/Why-is-Polaris-North-Star-flashing?share=1
See:
https://explainingscience.org/2020/09/25/the-changing-pole-star/
* Cepheid variable star: one of a class of
variable stars whose periods (i.e., the time for one complete cycle of brightening and dimming) of variation are closely related to their luminosity and that are therefore useful in measuring interstellar and intergalactic distances as standard candles.
Most Cepheid variable stars are spectral
type F (moderately hot) at maximum luminosity and
type G (cooler and Sun-like) at minimum. The
prototype star is
Delta Cephei, the variability of which was discovered by
John Goodricke in 1784. In 1912
Henrietta Leavitt of Harvard Observatory discovered the aforementioned period-luminosity relationship of the Cepheids.
Cepheids are now considered to fall into two distinct classes. The classical Cepheids have periods from about 1.5 days to more than 50 days and belong to the class of relatively young
stars found largely in the spiral arms of
galaxies and called
Population I.
Population II Cepheids are much older, less luminous, and less massive than their Population I counterparts. They fall into two groups—W Virginis stars with periods greater than about 10 days and BL Herculis stars with periods of a few days.
Classical Cepheids exhibit a relation between period and luminosity in the sense that the longer the period of the star, the greater its
intrinsic brightness; this period-luminosity relationship has been used to establish the distance of remote stellar systems. The absolute magnitude of a classical Cepheid can be estimated from its period. Once this is known, the distance of the star can be deduced from a comparison of absolute and apparent (measured) magnitudes. Population II Cepheids likewise obey a period-luminosity relationship, but it is different from that of the classical Cepheids. Since Population II Cepheids are less luminous than classical Cepheids, they are less useful as distance indicators.
See:
https://www.britannica.com/science/Cepheid-variable
The North Star, Pole Star or Polaris – is famous for holding nearly still in our sky while the entire northern sky moves around it. That’s because it’s located very close to the
north celestial pole, the point around which the entire northern sky apparently turns. Although it’s a common belief, Polaris is
not the brightest star in the nighttime sky. In fact, it’s only the
48th brightest star. But you can find it easily, and, once you do, you’ll see it shining in the northern sky every night from Northern Hemisphere locations.
Even when the
full moon obscures a good deal of the starry heavens, the North Star is relatively easy to see. That fact has made this star a boon to travelers throughout the Northern Hemisphere, both over land and sea. So finding Polaris means you know the direction north.
Best of all, you can readily find Polaris by using the prominent group of stars known as the
Big Dipper, called the Plough in the United Kingdom, which may be the Northern Hemisphere’s most famous star pattern. To locate Polaris, all you have to do is to find the Big Dipper
pointer stars Dubhe and Merak. These two stars outline the outer part of the Big Dipper’s bowl. Simply draw a line from Merak through Dubhe, and go about five times the Merak/Dubhe distance to Polaris.
Even when the
full moon obscures many stars, the North Star is relatively easy to see. That has made this star a boon to travelers throughout the Northern Hemisphere, on both land and sea. Finding Polaris means you know which direction is north.
Best of all, you can readily find Polaris by using the prominent group of stars known as the
Big Dipper, which may be the Northern Hemisphere’s most famous historical star pattern. To locate Polaris, all you have to do is to find the Big Dipper
pointer stars Dubhe and Merak. These two stars outline the outer part of the Big Dipper’s bowl. Simply draw a line from Merak through Dubhe, and go about five times the Merak/Dubhe distance to Polaris.
The Big Dipper is an object formed by seven bright stars in the constellation of Ursa Major, known as the Great Bear. It is one of the most recognizable star patterns in the night sky. This asterism is well-known in many cultures and goes by many other names, including the Plough, Charles' Wain, the Wain, the Northern Waggoner (In 1584 the Dutch pilot Lucas Janszoon Waghenaer published a volume of navigation principles, tables, charts, and sailing directions, which served as a guide for other such books for the next 200 years. These "Waggoners" as they came to be known, were very popular; and in 1588, an English translation of the original book was made.
Also see Edmund Spenser,
The Faerie Queene, Book I, Canto II, Stanza 1, lines 1-5,
"By this the Northerne wagoner had set
His sevenfold teme behind the stedfast starre,
That was in Ocean waves yet never wet,
But firme is fixt, and sendeth light from farre
To all that in the wide deepe wandring arre.),
also the Great Wagon, the Drinking Gourd, Northern Ladle, the Great Bear, Saptarishi, and the Saucepan.
Hartmann352
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