Polaris, the North Star lies at the end of the handle of the Little Dipper, whose stars are rather faint. Its four faintest stars can be blotted out with very little moonlight or street lighting. The best way to find your way to Polaris is to use the so-called pointer stars in the bowl of the Big Dipper, Dubhe and Merak.
Just draw a line, between these two stars and prolong it about 5 times, and you eventually will arrive in the vicinity of Polaris. Exactly where you see Polaris in your northern sky depends on your latitude. From New York City it's almost halfway from the horizon to the overhead point called the zenith. At the North Pole , you would find it directly overhead.
At the equator, Polaris would appear to sit right on the horizon. Alpha Ursae Minoris is classified as a Cepheid variable. It is the nearest Cepheid variable to Earth. The star is believed to be much brighter today than it was when Ptolemy observed it. Polaris is really a multiple star system, consisting of the main star, two smaller companion stars, and two more distant components. The main component in the system is an F7 yellow supergiant with a mass 4. The two smaller stars are main sequence stars belonging to the spectral classes F3 and F6.
Polaris was not always the North Star, nor will it stay the northernmost star forever. In approximately 14, years, the bright star Vega in the constellation Lyra will take over, until Polaris takes over again in another 14, years. After the 21st century, the celestial pole will move away from Polaris and, by the 41st century, it will come near Gamma Cephei in Cepheus constellation. It lies at a distance of With a surface temperature of 4, K, Kochab is times more luminous than the Sun.
Kochab and Pherkad served as twin pole stars from BC to AD, but neither of them was as close to the celestial pole as Polaris is today.
Gamma Ursae Minoris is also classified as a shell star, which means that it has a circumstellar disk of gas around the equator. The star is times more luminous than the Sun and has a radius 15 times solar. However, the Earth's axis wobbles on a 26,year cycle, in a phenomenon known as precession.
The celestial pole therefore shifts as the centuries go by, meaning different stars have been the North Star at different times. Polaris is actually still drawing closer to the pole, and on March 24, , it will be as close to the pole as it ever will come — just Finally, many people believe that the North Star is the brightest star in the sky.
This is not true; Polaris actually ranks only 48th in brightness. The brightest is Sirius , the Dog Star. He writes about astronomy for Natural History magazine, the Farmer's Almanac and other publications, and he is also an on-camera meteorologist for News 12 Westchester, N.
Originally published on Space. Join our Space Forums to keep talking space on the latest missions, night sky and more! Many tales are associated with the Little Dipper, as it received great attention throughout the years. The Little Dipper should not be confused with the constellation of Ursa Minor, it is just a part of it.
With that being said, let us see what is the Big Dipper, and which stars are part of it. The Little Dipper is an asterism made up of seven stars. It is located in Ursa Major , which spreads for over square degrees in the sky, making it the 56 th largest constellation. The asterism gets usually confused for the entire constellation, but we have to keep in mind that the Little Dipper is not and will never be a constellation.
Even though the brightest stars of Ursa Major form the Little Dipper, this asterism is not an exceptionally bright one. Besides its most shining star, Polaris , only two other stars, Kochab and Pherkad, can be seen from an urban area during nighttime. Three of its stars, namely Polaris, Yildun, and Urodelus, are known as "the handle" of the dipper, and the other four, Kochab, Pherkad, Anwar al Farkadain, and Akhfa al Farkadain, as "the bowl" or "the body. Polaris is the brightest star of this asterism and the current North Star since it is near the celestial North Pole.
It is a yellow-white supergiant with an apparent magnitude of 2. Polaris is also the 50 th brightest star in the sky, and it is somewhere around 2, brighter than our Sun. In order to find the Little Dipper, you need to firstly find the Big Dipper. Once you have located it, continue the line between Merak and Dubhe upwards, and you will reach the North Star, which is the brightest star of the Little Dipper.
Afterward, it will be easy to spot the entire asterism as it has a unique pattern.
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