STAR SYSTEM. Polaris is not a single star, but a multiple star system. The main component, Alpha Ursae Minoris Aa, is an evolved yellow supergiant star belonging to the spectral class F7. It is 2,500 times more luminous than the Sun, 4.5 times more massive, and has a radius 46 times that of the Sun.
This of course begs the query “What is the leading edge of the Polaris constellation?”
The leading edge (defined by the stars Dubhe and Merak ) is referenced to a clock face, and the true azimuth of Polaris worked out for different latitudes. The apparent motion of Polaris towards and, in the future, away from the celestial pole, is due to the precession of the equinoxes.
In 2019, a study by R. I. Anderson gave a period of 29.32 ± 0.11 years with an eccentricity of 0.620 ± 0.008. There were once thought to be two more widely separated components—Polaris C and Polaris D—but these have been shown not to be physically associated with the Polaris system.
Where is Polaris located on the sky?
For observers at the equator, Polaris sits right on the horizon. The star clmbs higher in the sky the farther north you go and drops below the horizon for observers in the southern hemisphere. Polaris was used as the pole star by navigators at least from Late Antiquity.
What kind of star is Altair?
Altair forms a line of stars known as the Shaft of Aquila, or the Family of Aquila, along with the stars Beta and Gamma Aquilae, better known by their proper names, Alshain and Tarazed. Altair has three optical companions, stars that are not physically close to it but appear along the same line of sight in the sky.
At a distance of 16.73 light years, Altair is one of the nearest stars to Earth visible to the unaided eye. Altair is one of the vertices of the Summer Triangle, a prominent asterism also formed by the bright stars Vega in the constellation Lyra and Deneb in Cygnus. Altair is the nearest of the three stars.
What is Altair in the Summer Triangle?
Altair is one of the vertices of the Summer Triangle, a prominent asterism also formed by the bright stars Vega in the constellation Lyra and Deneb in Cygnus. Altair is the nearest of the three stars. It is also the coolest and least luminous. It appears brighter than Deneb, but not quite as bright as Vega.
What is Altair (Alpha Aquilae)?
Altair is also known as Alpha Aquilae, and it is the brightest star in the constellation Aquila the Eagle. What’s more, stargazers know Altair as part of an entirely different and much-larger – but very recognizable – pattern.