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Pi² Ursae Majoris
4 Ursae Majoris (sometimes abbreviated 4 Uma) is the Flamsteed designation of a star in the northern circumpolar constellation of Ursa Major. It also bears the Bayer designation of Pi2 Ursae Majoris (Pi2 UMa, π2 Ursae Majoris, π2 UMa) and is traditionally named Muscida. With an apparent visual magnitude of +4.6, this star is visible from suburban or darker skies based upon the Bortle Dark-Sky Scale. From parallax measurements made during the ''Hipparcos'' mission, this star is at a distance of from Earth. , one extrasolar planet has been confirmed to be orbiting the star. Properties This star has a stellar classification of K2 III, indicating that, at an estimated age of around four billion years, it is an evolved star that has reached the giant stage. It has a mass about 1.2 times larger than the Sun, but has expanded to 18 times the Sun's girth. The effective temperature of the star's outer atmosphere is . This heat gives it the cool, orange-hu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bayer Designation
A Bayer designation is a stellar designation in which a specific star is identified by a Greek or Latin letter followed by the genitive form of its parent constellation's Latin name. The original list of Bayer designations contained 1,564 stars. The brighter stars were assigned their first systematic names by the German astronomer Johann Bayer in 1603, in his star atlas '' Uranometria''. Bayer catalogued only a few stars too far south to be seen from Germany, but later astronomers (including Nicolas-Louis de Lacaille and Benjamin Apthorp Gould) supplemented Bayer's catalog with entries for southern constellations. Scheme Bayer assigned a lowercase Greek letter (alpha (α), beta (β), gamma (γ), etc.) or a Latin letter (A, b, c, etc.) to each star he catalogued, combined with the Latin name of the star's parent constellation in genitive (possessive) form. The constellation name is frequently abbreviated to a standard three-letter form. For example, Aldebaran in the constellation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hipparcos
''Hipparcos'' was a scientific satellite of the European Space Agency (ESA), launched in 1989 and operated until 1993. It was the first space experiment devoted to precision astrometry, the accurate measurement of the positions of celestial objects on the sky. This permitted the first high-precision measurements of the intrinsic brightnesses (compared to the less precise apparent brightness), proper motions, and parallaxes of stars, enabling better calculations of their distance and tangential velocity. When combined with radial velocity measurements from spectroscopy, astrophysicists were able to finally measure all six quantities needed to determine the motion of stars. The resulting ''Hipparcos Catalogue'', a high-precision catalogue of more than 118,200 stars, was published in 1997. The lower-precision ''Tycho Catalogue'' of more than a million stars was published at the same time, while the enhanced Tycho-2 Catalogue of 2.5 million stars was published in 2000. ''Hipparcos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
