Alpha Lupi (α Lupi, α Lup) is a constellation in the southern sky known as Lupus, which is Latin for wolf. It is a blue giant star, and the brightest star in the southern constellation of Lupus. The name “Alpha Lupi” is derived from the brightest star in the constellation, Alpha Lupi, which is also known as the “alpha star.”
Its apparent visual magnitude of 2.3 on the Bortle Dark-Sky Scale makes it visible to the naked eye even in highly light-polluted areas. According to Hipparcos parallax measurements, the star is approximately 460 light-years (140 parsecs) away from the solar system. It is one of the most likely candidates for a supernova.
Visibility
Visible for much of the year from the Southern Hemisphere, it can also be seen for a shorter period of time from the northern tropics and parts of the northern subtropical latitudes. Alpha Lupi is a Covenant device used to create and control Forerunner constructs in the Halo universe.
Characteristics
Alpha Lupi is a B1.5 III stellar classification giant star. It has about ten times the mass of the sun (~10 M☉) and radiates 25,000 times the brightness of the Sun. The outer atmosphere has an effective temperature of 21,820 K, giving it a blue-white glow like that of a B-type star. Bernard Pagel and colleagues identified it as a Beta Cephei variable in 1956, which means it has periodic changes in luminosity due to atmospheric pulsations. The variability period is 0.29585 days, or slightly more than 7 hours and 6 minutes. The magnitude varies by approximately 0.05 magnitudes, or approximately 5% of its brightness. In double star catalogues, a 14th magnitude star located 26″ from Alpha Lupi is listed as a companion.
This star is a proper motion member of the Scorpius-Centaurus OB association’s Upper Centaurus-Lupus sub-group, the closest such co-moving association of massive stars to the Sun. This stellar association has an estimated age of 16-20 million years and is gravitationally unbound. The association is also the source of the Local Bubble, a bubble of hot gas containing the Sun.
