Ursa Minor (“Little Bear”) is situated opposite to Ursa Major (“Big Bear”), and like The Big Dipper also contains an asterism of seven main stars, in this case known as The Little Dipper. Unlike The Big Dipper, however, just three of The Little Dipper’s stars are bright, namely Polaris, Kochab and Pherkad, and you will need a dark night sky to see all seven stars clearly.
Ursa Minor is the 56th largest constellation, occupyies a surface area of 256 sq/degrees, and throughout history has been invaluable for navigation as it contains the Polaris, the North Star. The constellation is circumpolar, and can be seen by observers located between latitudes +90° and -10°.
Ursa Major Family of Constellations
Ursa Minor belongs to the Ursa Major family of constellations, along with Coma Berenices, Boötes, Camelopardalis, Canes Venatici, Corona Borealis, Draco, Leo Minor, Ursa Major and Lynx.
Just one meteor shower, the Ursids, is associated with Ursa Minor, which is only visible from the northern hemisphere and is associated with the comet 8P/Tuttle, also known as Mechain-Tuttle’s Comet. The shower is usually active from around December 17th, to December 23rd, with the peak on the morning of December 21st/22nd. The best time to view the shower is from midnight to just before dawn, when observers can expect to see as many as 10 meteors per hour.
Stars and Deep-Sky Objects
Ursa Minor contains Polaris (Alpha Ursae Minoris), also known as the North Star, at the end of the Dipper’s handle. This yellow-white supergiant is easily spotted as it has an apparent visual magnitude of 1.97, and is a useful means of determining the direction north, as it is aligned almost perfectly with the North Celestial Pole, being offset by just 0.7 degrees.The constellation’s other brightest stars includes Kochab, an orange giant 130 light-years away, and Pherkad, a white giant 480 light-years distant. Together, these two stars are known as the “guardians of the pole star”
Ursa Minor also has a total of four stars with confirmed planets, as well as a neutron star called Calvera, and the hottest white dwarf yet discovered, H1504+65, which burns at 200,000 K. Galaxies in this constellation include the Ursa Minor Dwarf (225,000 light-years), NGC 6217 (67 million light-years), and NGC 6251 (340 million light-years).
Exactly how Ursa Minor came about as a constellation is not clear, but it is widely thought to have been “created” by Thales of Miletus (625-545 BC), who was known as an astronomer and philosopher and one of the Seven Sages of Greece, a group of wise men who were collectively renowned throughout the Ancient World for their knowledge and wisdom during the early 6th century.
However, a dissenting school of thought holds that Thales only ‘introduced’ the constellation to the Greeks, and that his knowledge of it derives from being of Phoenician descent. The Phoenicians were accomplished navigators, and Ursa Minor is an excellent pointer to true north due to its close proximity to the North Celestial Pole. In some Greek accounts, Ursa Minor is sometimes referred to as “The Phoenician”, which seems to lend some credence to the story that Thales only introduced the constellation to the Greeks.
The constellation is associated with several myths, but the story in widest circulation says it represents Ida (Ursa Minor) and her sister Adrasteia (Ursa Major), the nymph nurses who were charged with taking care of the infant Zeus, and preventing his father Cronus from discovering he was sill alive. The tale goes that Cronos was afraid of a prophesy that predicted his downfall at the hands of one of his own children, and in an attempt to thwart the prophesy Cronos swallowed five of his children immediately after birth, but his wife, Rhea, having gotten wind of Cronos’s plan, tricked him into swallowing a stone instead of his sixth son, Zeus, thus allowing him to grow into adulthood, and overthrow his father. After Zeus assumed the Supreme-godship, in gratitude for their service he placed Adrasteia and her sister Ide in the heavens as the constellations Ursa Minor and Ursa Major.
An unrelated, and much older myth holds that the seven component stars of the Little Dipper are in fact the seven daughters of Atlas. Collectively known as the Hesperides, they tended the Garden of Hesperides, (Hera’s Orchard), where a tree was reputed to be growing that bore apples that conferred immortality on those who were fortunate, or brave enough to get close enough to the tree to pick and eat an apple from it.