Gamma Virginis “Porrima”: Twins Pulling Apart

Not far from Virgo’s beautiful blue Spica is the double star Gamma Virginis. Also known as Porrima, this star is the second brightest in the springtime constellation of Virgo. At first glance from a suburban location with light pollution, Porrima is a dim white star. However, looking through the telescope, one will find two white and pale yellow pinpoints of light near each other. What makes these set of stars stand out is their similarity to one another in magnitude and color.

Astronomers have studied this binary closely over the centuries. The stars are 38 light years away from earth, and it takes the companion star nearly 170 years to make one orbit. In 2007, the two stars made their closest approach tp each other and thus required large telescopes to split them. Now, the stars are moving apart again, so the casual observer with a smaller telescope should see both stars.

My Observations

Key Stats

Constellation	Virgo
Best Viewing	Spring
Visual Magnitude	+3.5 | +7.8
Absolute Visual Magnitude	+3.14
Distance from Earth	280 ly
Separation	3.1″ | 284 AU
Orbital Period	169 yrs
Milky Way Location	Orion Spur
My Viewing Grade	B

Sources and Notes

Porrima Banner by Second Digitized Sky Survey (DSS2), measuring 30 arcminutes across.

Sketch by Wayne McGraw

AKA: 29 Vir