The Sun was at the autumnal equinox in Libra until the year , when the precession of the equinoxes shifted the equinox to Virgo. The autumnal equinox will move to constellation Leo in the year The Romans were not the first to associate Libra with the idea of balance.
The Babylonians called it ZIB. Beta Librae is the brightest star in the constellation. It has an apparent magnitude of 2. It has the stellar classification of B8 V, which means that it is a blue-white dwarf. It has 4. Beta Librae is classified as a single star, but it shows small periodic variations in luminosity 0. Alpha Librae is the second brightest star in Libra. It is a multiple star system whose two brightest components form a binary star and share a common proper motion through space.
They are suspected members of the Castor Moving Group of stars, which share a common origin about million years ago. Libra stars and the location of HD VandenBerg University of Victoria , G. Wilson Observatory , and D. Harmer NOAO. The Alpha Librae system lies close to the ecliptic and can be occulted by the Moon and, much less frequently, by planets. It will next be occulted by a planet Mercury on November 10, Alpha-1 Librae is the dimmer of the two main components in the system.
It has an apparent magnitude of 5. Alpha-1 Librae is a spectroscopic binary system with an orbital period of 5, days, with components separated by 0. The system has the stellar classification F4 and an apparent magnitude of 5. It is Alpha-2 Librae has an apparent magnitude of 2.
It is also a spectroscopic binary system, separated from Alpha-1 Librae by about 5, astronomical units. It has the stellar classification A3 and an apparent magnitude of 2.
The star KU Librae might be a fifth component in the Alpha Librae system, lying at a separation of 2. It shares a similar proper motion with the other components, but is a parsec away.
This is just close enough for KU Librae to be gravitationally bound to the other stars. It has an apparent magnitude of 3. Sigma Librae used to have the Bayer designation Gamma Scorpii even though it lies quite far from the border with Scorpius constellation. It only became Sigma Librae in the 19th century, and the designation was confirmed by the International Astronomical Union on July 31, Brachium is a semi-regular variable star with a single pulsation period of 20 days.
It exhibits small variations in magnitude of 0. HD is one of the oldest stars known, believed to have been created shortly after the Big Bang. Nicknamed Methuselah, it is a subgiant star that is very metal poor and consists almost entirely of hydrogen and helium.
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Share Flipboard Email. Carolyn Collins Petersen. Astronomy Expert. Carolyn Collins Petersen is an astronomy expert and the author of seven books on space science. She previously worked on a Hubble Space Telescope instrument team. Facebook Facebook. Featured Video. Cite this Article Format.
Petersen, Carolyn Collins. How to Spot the Scorpius Constellation. Some studies have suggested Gliese d and Gliese g are habitable — in a zone near their star where water would exist on the surface — but their existence is not fully proven.
Gliese c was discovered in ; at first, scientists suggested there could be liquid water on its surface, but follow-up studies in and by different teams suggested the planet is so close to its star that it may have a more Venus-like environment runaway greenhouse effect, hot surface.
Also within Libra is the bright star cluster NGC , which is 40, light-years from Earth with an integrated magnitude of 9. The association with scales and balance began with the ancient Babylonians, with the scales representing the balance between the seasons as well as day and night. The ancient Greeks viewed Libra as the claws of Scorpius reaching out.
To the Romans, Libra represented the scales of justice being held by the goddess Virgo or Astraea. In astrology, which is not a science , Libra is the seventh sign in the Zodiac and represents those born between Sept.
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