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Ursa Minor: Difference between revisions
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Ursa Minor (Latin: "Smaller She-Bear", contrasting with Ursa Major), also known as the Little Bear, is a constellation in the northern sky. Like the Great Bear, the tail of the Little Bear may also be seen as the handle of a ladle, hence the name Little Dipper. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations. Ursa Minor is notable as the location of the north celestial pole, although this will change after some centuries due to the precession of the equinoxes. | Ursa Minor (Latin: "Smaller She-Bear", contrasting with Ursa Major), also known as the Little Bear, is a constellation in the northern sky. Like the Great Bear, the tail of the Little Bear may also be seen as the handle of a ladle, hence the name Little Dipper. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations. Ursa Minor is notable as the location of the north celestial pole, although this will change after some centuries due to the precession of the equinoxes. | ||
Polaris, the brightest star in the constellation, is a yellow-white supergiant and brightest Cepheid variable star in the night sky, ranging from apparent magnitude 1.97 to 2.00. Beta Ursae Minoris, also known as Kochab, is only slightly fainter, with its apparent magnitude of 2.08. An ageing star that has swollen and cooled to become an orange giant, it has a been found to have a planet orbiting it in 2014. It and magnitude 3 Gamma Ursae Minoris have been called the 'guardians of the pole star'. Three other stellar systems have been discovered to contain planets.<ref>[http://en.wikipedia.org/wiki/Ursa_Minor Ursa Minor]</ref> | Polaris, the brightest star in the constellation, is a yellow-white supergiant and brightest Cepheid variable star in the night sky, ranging from apparent magnitude 1.97 to 2.00. Beta Ursae Minoris, also known as Kochab, is only slightly fainter, with its apparent magnitude of 2.08. An ageing star that has swollen and cooled to become an orange giant, it has a been found to have a planet orbiting it in 2014. It and magnitude 3 Gamma Ursae Minoris have been called the 'guardians of the pole star'. Three other stellar systems have been discovered to contain planets. | ||
Ursa Minor is notable as the location of the north celestial pole, although this will change after some centuries due to the precession of the equinoxes. It is bordered by [[Camelopardalis]] to the west, [[Draco]] to the west, and [[Cepheus]] to the east. Covering 256 square degrees, it ranks 56th of the 88 constellations in size. Ursa Minor is colloquially known as the Little Dipper because its seven brightest stars seem to form the shape of a dipper (ladle or scoop). The star at the end of the dipper handle is [[Polaris]], the North Star. Polaris can also be found by following a line through the two stars that form the end of the "bowl" of the Big Dipper, a nearby asterism found in the constellation [[Ursa Major]]. The four stars constituting the "bowl" of the little dipper are unusual in that they are of second, third, fourth, and fifth magnitudes. Hence, they provide an easy guide to determining what magnitude stars are visible, useful for city dwellers or testing one's eyesight. | |||
<ref>[http://en.wikipedia.org/wiki/Ursa_Minor Ursa Minor]</ref> | |||
==Babylonian Astronomy== | ==Babylonian Astronomy== | ||