One of the most easily recognized stars in the sky is Polaris. It is located near the northern celestial pole, and is the brightest star in the night sky. It is also one of the easiest stars to find, since it shines brightly in the northern sky on a daily basis. So, how do you spot it? Here are some tips: Keep an eye out for streetlight and moonlight. You can also look for the “Pointer” stars (Dubbhe and Merak) – these two are five times brighter than Polaris.
Although Polaris is visible to the naked eye, it is not particularly bright. In fact, it is the 48th brightest star in the sky and the ninth brightest in the constellation of Ursa Minor. It is a yellow supergiant, but because it is so far away, it looks faint. As a triple-star system, Polaris consists of the yellow supergiant Polaris Aa and two white main sequence stars.
In addition to pointing to the North Pole, Polaris also marks the closest location to the north celestial pole. The star is in the same direction as the Earth’s north axis. Therefore, for hypothetical observers at the North Pole, Polaris would be overhead. This is why it does not rise or set, but instead appears motionless in the sky. Its close proximity to the North Pole makes it important for navigation and astrometry.
Its brightness varies from magnitude 1.86 to 2.13. It had been over 0.1 magnitude before 1963, but it gradually declined until 1966. At that time, the star’s brightness decreased dramatically to less than 0.05. After that, the star has varied unpredictably and has been close to its original magnitude. The 2008 paper noted that its brightness has even increased. If this trend continues, Polaris is a very visible object in the night sky.
The Polaris star is a yellow supergiant. It has a rotational period of 119 days. Its color is blue and has 112% solar metallicity. It is the 50th brightest star in the night sky. Its brightness has a high luminosity, and is a double-star system. Its three stars, named ‘Pilot’, are similar in size and brightness. The brightest of these is called Polaris Aa, and the star is 5.4 solar masses in mass.
The magnitude of Polaris is 0.66 degrees away from the pole of rotation. The star moves around the pole in a circle 1.3 deg in diameter. It will be closest to the pole soon after the year 2100. Because of the precession of the earth’s axis, the right ascension of Polaris changes rapidly. It is the only object in the sky that has a fixed azimuth. But this is only one of the many ways to see Polaris.
The light of Polaris varies, and the star is the most obvious source of light. However, the star is not visible to the naked eye, and therefore, it is important to know where it is in order to find it in the sky. In the constellation of Ursa Minor, the brightest star in the constellation is the Sun. This polaris is the best spot to locate the southern celestial pole. A fainter one is Jupiter.
Another way to find Polaris is to observe its brightness. Its brightness varies from magnitude 1.86 to 2.13. In Antiquity, it was more than 0.1 magnitude. It was used as a single star, but not until the mid-16th century when it became visible to the human eye. By contrast, it is now ranked as the fifty-first brightest star in the night sky. Its light is also the closest star to the Earth.
The primary star of Polaris is the star ‘North Star’. Its radii are 0.5° apart, and its amplitude is 18.8 arcseconds. The other star, Polaris B, is a main sequence star. It is the northernmost of the two stars. Its radii are about six degrees. The arcseconds it takes to orbit the planet is 0.082°N.
Unlike the North Star, Polaris is not an absolute guide to latitude on Earth. It has been a great help for travelers in the Northern Hemisphere for centuries. It is a good indicator of the direction north, so it can be seen at any time. And, it is the brightest star in Ursa Minor. Interestingly, it is the nearest star to the North celestial pole. If you are in the northern hemisphere, it is easy to locate the “North Star” on a map.