At magnitude 2.85 and third brightest in the constellation Virgo, Vindemiatrix recieved the Bayer designation Epsilon Virginis. The name Vindemiatrix came from the Greeks, was translated and feminized into Latin, and means "the Grape Gatherer." The first visibility of the star in morning light ("heliacal rising") indicated that it was time to harvest the grapes. An alternative name derived from Arabic, Almuredin, means the same thing, and was also translated from the original Greek. Additional medieval names are Alaraph, Provindemiator, Protrigetrix, and Protrygetor.
Properties and Evolution
Vindemiatrix is a yellow class G8 III giant a bit cooler than the Sun (4990 K). As a giant, however, it is considerably more luminous than the Sun. From a distance of 102 light years, its luminosity is 83 suns, with a radius 12 times solar. The star seems to be a about 15% richer than the Sun in metals, and is somewhat distinguished by having most of its motion perpendicular to our line of sight, making it appear to move rather rapidly against the background stars (0.2 arcsec per year).
Much more significantly, Vindemiatrix is a rather powerful X-ray source, implying considerable magnetic surface activity. Its total X-ray radiation is almost 300 times the Sun's. Though Vindemiatrix has ceased fusing hydrogen to helium in its core, its exact internal structure is uncertain. At three solar masses, it probably began life as a blue-white class B star, and is now in transition to fusing its internal helium.
There is evidence that Vindemiatrix is part of the Hyades group, associated with the cluster of that name in the constellation Taurus.
[Adapted from STARS by Jim Kaler, Professor Emeritus of Astronomy, University of Illinois]