![]() Though early estimates of age have been reduced by further study, the star remains an enigma as it is dated at 14.46 billion years with an uncertainty of 800 million years, according to Constellation Guide. ![]() This metal-poor subgiant is predominantly made of hydrogen and helium and is therefore clearly old, but when it was first discovered it appeared to be 16 billion years old, older than the age of the universe itself - 13.8 billion years. Located around 190 light-years from Earth, is found in Libra. ![]() One of the most extraordinary stars we have yet to discover, HD 140283 or Methuselah. Libra is also the constellation that hosts the bright star cluster NGC 5897 located 40,000 light-years from Earth. Another star of note in the constellation of Libra is the red giant star Brachium ("arm") or Sigma Librae (σ Lib). These are the second brightest star Alpha Librae (α Lib) which despite its alpha designation, is also called Zubenelgenubi ("southern claw") - a binary star located 77 light-years from Earth - and Gamma Librae (γ Lib), an orange giant of magnitude 3.9, lying around 152 light-years from Earth, according to the astronomy website Constellation Guide. Β Lib, also called Lanx Australis ("the southern scale"), makes up the upper part of the scale linking the two balances, which hang from the triangle at an angle along with two of the constellation's other brightest stars. According to Burnham's Celestial Handbook (opens in new tab) Amateur astronomer Willian Tyler Olcott once said that Zubeneschamali is "… the only naked-eye star that is green in color." Most modern astronomers consider it white or blue. The stars of Libra are fairly faint with its brightest star, Zubeneschamali or Beta Librae (β Lib) -a blue dwarf star which is located 160 light-years from Earth - having a magnitude of 2.7. In 2439 the autumnal equinox will shift again, this time moving to the constellation Leo. ![]() Until 729 BCE the sun was in autumnal equinox in Libra, at this time precession of the equinoxes shifted the equinox to Virgo. Libra also borders the constellations of Serpens Caput, Hydra, Centaurus, Lupus, and Ophiuchus. The constellation is positioned between Scorpius on the east and Virgo on the west. In the southern sky, it can be found at about 15 hours 30 minutes right ascension and 15° south declination according to Britannica (opens in new tab).
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