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Centaurus: the story on HearLore | HearLore
Centaurus
Alpha Centauri, the closest star system to the Sun, sits just 4.4 light-years away, yet for centuries it remained a single point of light to the naked eye. This triple star system, traditionally known as Rigil Kentaurus or Toliman, consists of two yellow-hued stars orbiting each other every 80 years, while a faint red dwarf named Proxima Centauri circles them at a distance of approximately one million years. Proxima, though appearing almost 2 degrees away from the main pair, is actually the nearest individual star to Earth, and it is a volatile flare star that can brighten by over a magnitude in minutes-long outbursts. The primary and secondary stars of the Alpha pair will next appear closest as seen from Earth's telescopes in 2037 and 2038, presenting the third-brightest star in the night sky when viewed together. This proximity makes Alpha Centauri a focal point for astronomers, as its high proper motion means it will be a mere half-degree from Beta Centauri in approximately 4000 years, altering the visual landscape of the southern sky for future observers.
The Diamond Star
Deep within the constellation lies a white dwarf star known as BPM 37093, which scientists have nicknamed Lucy after the Beatles song Lucy in the Sky with Diamonds. This celestial body is unique because its carbon atoms are thought to have formed a crystalline structure, effectively making it a diamond star on a massive scale. While diamond on Earth consists of carbon arranged in a specific lattice, the carbon in BPM 37093 forms a similar crystalline structure, creating a solid core of immense size and density. The discovery of this crystalline state provides astronomers with a rare glimpse into the end stages of stellar evolution, where the core of a dying star cools and solidifies over billions of years. This object stands in stark contrast to the fiery giants and volatile flares found elsewhere in Centaurus, offering a quiet, solid anchor in the cosmic narrative of the constellation.
The Giant Cluster
Omega Centauri, despite its stellar designation, is not a star but a naked-eye globular cluster located 17,000 light-years away with a diameter of 150 light-years. It is the largest and brightest globular cluster in the Milky Way, containing several million stars and shining at ten times the size of the next-largest cluster. At an overall magnitude of 3.7, it is the most luminous globular cluster in the galaxy, emitting over one million solar luminosities. The cluster's stars have an average age of 12 billion years, leading to the suspicion that Omega Centauri was once the core of a dwarf galaxy that had been absorbed by the Milky Way. Determined to be nonstellar in 1677 by the English astronomer Edmond Halley, its status as a globular cluster was confirmed by James Dunlop in 1827. To the unaided eye, it appears fuzzy and is approximately half a degree in diameter, the same size as the full Moon, making it one of the most impressive deep-sky objects visible from Earth.
What is Alpha Centauri and how far is it from Earth?
Alpha Centauri is the closest star system to the Sun and sits just 4.4 light-years away from Earth. This triple star system consists of two yellow-hued stars orbiting each other every 80 years and a faint red dwarf named Proxima Centauri that circles them at a distance of approximately one million years.
What is the diamond star BPM 37093 in Centaurus?
BPM 37093 is a white dwarf star nicknamed Lucy that contains carbon atoms thought to have formed a crystalline structure. This celestial body effectively makes it a diamond star on a massive scale with a solid core of immense size and density.
What is Omega Centauri and how does it differ from a star?
Omega Centauri is a naked-eye globular cluster located 17,000 light-years away with a diameter of 150 light-years. It is the largest and brightest globular cluster in the Milky Way containing several million stars and shining at ten times the size of the next-largest cluster.
What is Centaurus A and what makes it unique?
Centaurus A is one of the closest active galaxies to Earth located 11 million light-years away and featuring a supermassive black hole at its core. This galaxy expels massive jets of matter that emit radio waves due to synchrotron radiation and contains dust lanes believed to be the result of a previous merger with another galaxy.
How did the Babylonians and Greeks name the Centaurus constellation?
The figure of Centaurus can be traced back to a Babylonian constellation known as the Bison-man which was depicted as a 4-legged bison with a human head. The Greeks later depicted the constellation as a centaur and gave it its current name mentioning it by Eudoxus in the 4th century BC and Aratus in the 3rd century BC.
What is PDS 70 and what discovery did it make in 2018?
PDS 70 is a low mass T Tauri star found in the constellation that captured the first conclusive image of a protoplanetary disk containing a nascent exoplanet named PDS 70b in July 2018. This discovery provides astronomers with a rare opportunity to study the formation of planets in real-time as the disk contains the raw materials necessary for planet formation.
Centaurus A, also known as NGC 5128, is one of the closest active galaxies to Earth, located 11 million light-years away and featuring a supermassive black hole at its core. This galaxy expels massive jets of matter that emit radio waves due to synchrotron radiation, creating a dramatic display of cosmic energy. Its dust lanes, which are not common in elliptical galaxies, are believed to be the result of a previous merger with another galaxy, likely a spiral galaxy. The galaxy appears in the optical spectrum as a fairly large elliptical galaxy with a prominent dust lane, and its overall magnitude of 7.0 means it has been seen under perfect conditions with the naked eye. In small telescopes, the dust lane is not visible, but it begins to appear with about 4 inches of aperture under good conditions. In large amateur instruments, above about 12 inches in aperture, the dust lane's west-northwest to east-southeast direction is easily discerned, revealing the violent history of the galaxy's formation.
The Ancient Bison
The figure of Centaurus can be traced back to a Babylonian constellation known as the Bison-man, which was depicted in two major forms: a 4-legged bison with a human head, or a being with a man's head and torso attached to the rear legs and tail of a bull or bison. This being was closely associated with the Sun god Utu-Shamash from very early times, and by the late 3rd millennium the Bison-man had been replaced by a new constellation, the Wild Boar. The Greeks later depicted the constellation as a centaur and gave it its current name, mentioning it by Eudoxus in the 4th century BC and Aratus in the 3rd century BC. In the 2nd century AD, Claudius Ptolemy catalogued 37 stars in Centaurus, including Alpha Centauri. Large as it is now, in earlier times it was even larger, as the constellation Lupus was treated as an asterism within Centaurus, portrayed in illustrations as an unspecified animal either in the centaur's grasp or impaled on its spear. The Southern Cross, which is now regarded as a separate constellation, was treated by the ancients as a mere asterism formed of the stars composing the centaur's legs.
The Southern Pointer
The two bright stars Alpha Centauri and Beta Centauri are used as southern pointer stars to help observers find the constellation Crux, the Southern Cross. Beta Centauri, also called Hadar and Agena, is a double star located 525 light-years from Earth, with a primary that is a blue-hued giant star of magnitude 0.6. The secondary is of magnitude 4.0 and has a modest separation, appearing only under intense magnification due to its distance. The northerly star Theta Centauri, officially named Menkent, is an orange giant star of magnitude 2.06 and is the only bright star of Centaurus that is easily visible from mid-northern latitudes. The Pointer is one of the asterisms used by Bugis sailors for navigation, called bintoéng balué, meaning the widowed-before-marriage, and is also called bintoéng sallatang meaning southern star. This navigational utility highlights the practical importance of the constellation for ancient mariners and modern astronomers alike, serving as a guide to the southern sky.
The Crystalline Disk
PDS 70, also known as V1032 Centauri, is a low mass T Tauri star found in the constellation that captured the first conclusive image of a protoplanetary disk containing a nascent exoplanet, named PDS 70b, in July 2018. This discovery provides astronomers with a rare opportunity to study the formation of planets in real-time, as the disk contains the raw materials necessary for planet formation. The star itself is a T Tauri star, a type of young star that has not yet begun to fuse hydrogen in its core, and the presence of the protoplanetary disk suggests that the system is in the early stages of planetary development. The image captured by astronomers shows the disk in detail, revealing the structure and composition of the material that will eventually form planets. This observation marks a significant milestone in the study of exoplanets, as it provides direct evidence of planet formation in a system similar to our own solar system.