6/18/2023 0 Comments Cassiopeia constellation starsIt has an estimated age of 620 million years. The star has a mass of 1.7 solar masses and is 9.87 times more luminous than the Sun. The primary component in the system is an A-type subgiant locked in a 4,028-day orbit with a white dwarf companion. The binary pairs orbit each other with a period of 2,084 years. The Iota Ursae Majoris system consists of two pairs of binary stars. The star was nicknamed Dnoces (the word “second” backwards) by Apollo I astronaut Gus Grissom, after his colleague Edward H. Talitha (Iota Ursae Majoris) is the primary component in a multiple-star system located 47.3 light-years away. The two components have an orbital period of 230 days. The companion lies at a physical separation of only 0.2 astronomical units (Earth–Sun distances). The star has a radius 75 times that of the Sun and is between 977 and 1,200 times more luminous than our star. It has the stellar classification M0 III ab. The primary component is a red giant on the asymptotic giant branch (AGB). It shines at magnitude 3.06 and is the eighth brightest star in Ursa Major. Tania Australis (Mu Ursae Majoris) is a binary star located 183 light-years away. It has an estimated age of 380 million years. With an effective temperature of 9,247 K, it is 37 times more luminous than the Sun. The star has a mass of 2.11 solar masses and a radius 2.3 times that of the Sun. It has a visual magnitude of 3.45 and lies 138 light-years away. Tania Borealis (Lambda Ursae Majoris) is a subgiant star of the spectral type A2 IV. The paws of the Great Bear, image: Stellarium Tania Borealis and Tania Australis The brighter pair has the spectrum of a main sequence star of the spectral type F8.5: V, and the companion pair has the stellar classification G2 V, indicating a yellow dwarf. The four stars have masses of 0.97 (Xi UMa Aa), 0.38 (Xi UMa Ab), 0.86 (Xi UMa Ba), and 0.14 (Xi UMa Bb) solar masses. The two components of Xi UMa A have an orbital period of 669 days, while the components of Xi UMa B complete an orbit every 3.98 days. The two main components, Xi UMa A and Xi UMa B, are separated by 2.3 arcseconds and orbit each other with a period of 59.84 years. The star system lies 29 light-years away and has an apparent magnitude of 4.41. The companion is a 10th-magnitude star at an angular separation of 7.1 arcseconds.Īlula Australis (Xi Ursae Majoris) is the primary component in a multiple-star system composed of two pairs of single-lined spectroscopic binary stars and two other components. The star has a radius 57.07 times that of the Sun and is about 775 times more luminous than our star. The primary component is an orange giant of the spectral type K3 III. Alula Borealis and Alula AustralisĪlula Borealis (Nu Ursae Majoris) is a double star located approximately 399 light-years away. The faintest, Alula Australis (Xi UMa), has an apparent magnitude of 4.264 and lies 29 light-years away. It shines at magnitude 3.06 from a distance of 183 light-years. Tania Australis (Mu UMa) is the brightest of the six stars. The name Talitha is derived from the Arabic Al Fiḳrah al Thalitha, “the third leap (of the gazelle).” Alkaphrah is a corrupted form of the traditional name Alkafzah, derived from the Arabic al-qafzah, meaning “the leap.” Talitha and Alkaphrah mark the third leap. The six stars that form the Three Leaps of the Gazelle, image: Wikisky All six star names are derived from phrases that refer to the Three Leaps asterism. Talitha and Alkaphrah were historically known as Talitha Borealis and Talitha Australis, but when the International Astronomical Union (IAU) set out to standardize the proper names of stars in the 2010s, the other traditional name of Kappa UMa, Alkaphrah, was approved for the star. The first leap is marked by the stars Alula Borealis (Nu Ursae Majoris) and Alula Australis (Xi Ursae Majoris), the second leap by Tania Borealis (Lambda Ursae Majoris) and Tania Australis (Mu Ursae Majoris), and the third leap by Talitha (Iota Ursae Majoris) and Alkaphrah (Kappa Ursae Majoris). In Arabic lore, the three pairs of stars represented the three leaps of a gazelle that dashed off across a large pond after being startled by the celestial Lion. The Three Leaps asterism has its origins in Arabic astronomy. They shine at magnitudes 3.06 – 4.26 and can be spotted between the Big Dipper and the Sickle of Leo on a clear night. The six stars mark the paws of the Great Bear. The Three Leaps of the Gazelle is an asterism formed by three pairs of stars in the constellation Ursa Major.
0 Comments
Leave a Reply. |