ZAVIJAVA (Beta Virginis). A string of stars to the northwest of Spica in Virgo (Vindemiatrix, Delta Virginis, Porrima, Zaniah, and Beta Virginis) called "awwa" by the Arabians of old (which vaguely refers to a kennel and a barking dog, though the meaning is disputed) makes a sharp bend at Porrima, which in honor of the "turning" was once named Zavijava, "the angle." The name, however, is now erroneously (though permanently) applied to the Beta star, which lies in western Virgo south of Leo's Denebola. Not only does Beta not really "own" its own proper name, it does not even fulfill the expectation of its "beta-hood" to be the second brightest star. At the bright end of fourth magnitude (3.61), it ranks fifth in the constellation behind Spica (Alpha), Porrima (Gamma, a double star), Vindemiatrix (Epsilon), Delta, even Zeta Vir. Zavijava is also not terribly radiant; its modest apparent brightness (enough to be a prominent part of its constellation and the "awwa") owes itself to closeness, the star lying only 36 light years away. A class F (F9, almost G) dwarf, Beta Vir bears more resemblance to the Sun than to its constellation-mates, radiating only 3.5 solar luminosities from a 6150 Kelvin surface. From these parameters we derive a radius 1.65 times that of the Sun and a mass just 25 percent over solar, while age estimates range between 2.8 and 4.7 billion years. The star even rotates something like the Sun, with an equatorial speed of at least 3 kilometers per second, and a period less than a very solar 28 days (though the speed has been measured at up to 3 times higher). Zavijava does have some distinctiveness, however, as it is metal-rich, its iron content 30 percent higher than solar. It is also moving a bit more quickly than usual relative to the Sun, a modestly speedy 41 kilometers per second, roughly double that of most local stars. Unlike the Sun, it seems to possess relatively little magnetic activity. While X- ray emission supports the idea of a hot magnetically-heated corona, no magnetic field has actually been measured, nor is there any evidence for a sunlike chromosphere, the thin layer of hot gas that lies between the solar (or stellar) surface and the outer coronal halo.
Written by Jim Kaler. Return to STARS.