Vega

The brightest star in the constellation Lyra. The name Vega is derived from an Arabic phrase meaning "swooping eagle" or "swooping vulture". It also forms part of the Summer Triangle with Altair and Deneb, and is one of three stars which divide the Northern Hemisphere into thirds, the other two being Capella and Arcturus. It is the fifth brightest star in the night sky.

At only twenty-five light years distance, Vega is one of the closest stars to our own solar system. Its diameter is roughly three times that of our sun, and it is 50 times more luminous. Its much greater mass means that it burns its nuclear fuel at a far higher rate than the sun, and will burn out a lot sooner, probably in less than 1 billion years time. Being a brilliant white main sequence star, it forms the basis for the scale against which the apparent magnitude of all stars in the Terran sky are compared.

14,000 years ago Vega was the Northern pole star, a position occupied today by Polaris, and, at some point in the future, it will become the pole star again. This is due to the precession of the equinoxes, a term given to describe a steady rotation in the alignment of the Earth's North-South axis due to the gravitational interplay of the sun and the moon. For this reason, and because of its brightness, it has occupied a significant place in many previous cultures. Babylonians called it 'Dilgan', which means Messenger of Light, and the Hindu Vedas refer to it as 'Abhtlit', or Victorious, because its influence helped the Devas (gods) to overthrow the Asuras (demons). The Arabic name refers to the eagle or vulture, sent by Jupiter, that swooped down to retrieve the lyre of Orpheus from the river it was cast into, after Orpheus was torn to pieces by the Maenads.

Vega is surrounded by a disk of planetary debris, in which there may reside several planets capable of bearing life, including at least one massive planet more than twice the size of Jupiter, orbiting at a distance greater than that of Pluto around our own sun. However, it is highly unlikely that any planets orbiting Vega could ever reach the point of supporting complex life, due to the star's short life cycle. It is very hot, bright and quickly-rotating, and is probably only 350 million years old. If the time scales related to the development of life on Earth are any indication, Vega will burn out long before anything more notable than algae can develop on its planets.

To make matters worse depending on the various literature you read 'vega' is on occasion replaced with any of the following conventional greek letters; kappa, tau or lambda. (It appears that each new contributor to the theory of the option pricing had their own convention). In my notes taken from old university classes vega is written to resemble the small greek letter nu, ν, but with a further squiggle on the right-hand side of the letter, like you couldn't be bothered to lift your pen.

In Black-Scholes vega is used to measure the change in an option price in relation to a change in the perceived volatility of the market (i.e. risk). In broad terms a small value of vega implies that your model has a better estimate for the volatility of the market then for a large value of vega. This is because most models in the short term assume market volatility to be constant.

Asides from the origin in Babylonian astronomy as described by Dreamvirus above, Vega was also the name of a brand of Chevrolet car sold in the 70s, and is also used to describe a tobacco field in Cuba.

Ve"ga (vE"ga), n. (Astron.) [Ar. wAgi', properly, falling: cf. F. Wéga.]

A brilliant star of the first magnitude, the brightest of those constituting the constellation Lyra.

© Webster 1913

Ve"ga (?), n. [Sp.]

An open tract of ground; a plain, esp. one which is moist and fertile, as those used for tobacco fields. [Sp. Amer. & Phil. Islands]

© Webster 1913