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.