How to see it

Observers in the Northern Hemisphere can see the star Vega come into view in the northeast in mid-evening in May. Look for this star in the very early evening in June – high overhead on autumn evenings – in the northwestern quadrant of the sky on December evenings.

Vega is easily recognizable for its brilliance and blue-white color. You can also easily pick out its constellation Lyra, which is small and compact, and consists primarily of Vega and four fainter stars in the form of a parallelogram.

The little constellation Lyra has some interesting features. Near Vega is Epsilon Lyrae, the famed “double-double” star. Between the Gamma and Beta stars is the famous Ring Nebula, visible in small telescopes.

Vega is one of three stars in an asterism – or noticeable star pattern – called the Summer Triangle to the early evening sky. The other two stars in the Triangle are Deneb and Altair. You can see the Summer Triangle in the evening beginning around June, through the end of each year.

History and Myth

Vega’s constellation Lyra is said to be the harp played by the legendary Greek musician Orpheus. It’s said that when Orpheus played this harp, neither god nor moral could turn away. Vega is sometimes called the Harp Star.

Sky princess Tanabata and her lover Kengyu, a mortal, meet on a bridge of magpies across the Celestial River. It's said they come together in this way each year on the 7th night of the 7th moon. Image by Anhellica via Lilliacerise's blog

One of the prettiest stories relating to Vega is popular in Asia, although there are many variations. In Japan, Vega is sometimes called Tanabata (or Orihime), a celestial princess or goddess. She falls in love with a mortal, Kengyu (or Hikoboshi), represented by the star Altair. But when Tanabata’s father finds out, he is enraged and forbids her to see this mere mortal. Thus the two lovers are placed in the sky, where they are separated by the Celestial River, known to us as Milky Way. Yet the sky gods are kind. Each year, on the 7th night of the 7th moon, a bridge of magpies forms across the Celestial River, and the two lovers are reunited. Sometimes Kengyu’s annual trip across the Celestial River is treacherous, though, and he doesn’t make it. In that case, Tanabata’s tears form raindrops that fall over Japan.

Many Japanese celebrations of Tanabata are held in July, but sometimes they are held in August. If it rains, the raindrops are thought to be Tanabata’s tears because Kengyu could not meet her. Sometimes the meteors of the Perseid shower are said to be Tanabata’s tears.

Science

Vega is the 5th brightest star visible from Earth, and the 3rd brightest easily visible from mid-northern latitudes, after Sirius and Arcturus. At about 25 light-years in distance, it is the 6th closest of all the bright stars, or 5th if you exclude Alpha Centauri, which is not easily visible from most of the Northern Hemisphere.

NASA's Spitzer Space Telescope recently captured this image of the star Vega, located 25 light years away in the constellation Lyra. Spitzer was able to detect the heat radiation from the cloud of dust around the star and found that the debris disc is much larger than previously thought. Image Credit: NASA Jet Propulsion Laboratory

Size of star Vega in contrast to our sun. Image via RJHall at Wikimedia Commons

Vega’s distinctly blue color indicates a surface temperature of nearly 17,000 degrees F, making it about 7,000 degrees hotter than our sun. Roughly 2.5 times the diameter of the sun, and just less than that in mass, Vega’s internal pressures and temperatures are far greater than our sun, making it burn its fuel faster. This causes Vega to produce 35-40 times the energy of the sun, which in turn shortens its lifetime. At about 500 million years, Vega is already middle-aged. Currently it is only about a tenth the age of our sun, and will run out of fuel in another half-billion years.

In astronomer-speak, Vega is an “A0V main sequence star.” The “A0″ signifies its temperature, whereas the “V” is a measure of energy output (luminosity), indicating that Vega is a normal star (not a giant). “Main sequence” again testifies to the fact that it belongs in the category of normal stars, and that it produces energy through stable fusion of hydrogen into helium. With a visual magnitude (apparent brightness) of 0.03, Vega is only marginally dimmer than Arcturus, but with a distinctly different, cool-blue color.

Vega’s position is RA: 18h 36m 56.3s, dec: +38° 47′ 1.3″.