If you've ever been out for a night of stargazing, you've probably noticed: Some stars in the sky are brighter than others. A number of factors play a role in how bright stars appear to us on Earth, and astronomers have studied some of them extensively to understand why they are so luminous. One such star is Vega, a bright main-sequence star in the constellation Lyra.
Vega is easily one of the most visible stars in the night sky, but its importance goes much further. Astronomers have studied Vega for thousands of years and will likely continue to do so thanks to a special role Vega plays in our sky every 25,000 years or so. Here are some eye-opening facts about it.
1. Vega Is Known for Its Brightness
The star Vega is exceptionally eye-catching — it's the fifth brightest star in the night sky.
Vega is located in the constellation Lyra, which isn't a constellation most people can pick out when looking at the night sky. Nevertheless, it's among the most studied stars in the sky. Vega was the first star after our sun to be photographed and have its light spectrum recorded.
Stars can appear bright for several reasons: Because they are close or because they shine brightly. In the case of Vega, it's both. "Vega is bright because it's big, hot and close to us," explains astronomer Roy Alexander, who is an official International Dark-Sky Association delegate in the U.K. — among many other astronomy projects he's involved with.
Specifically, Vega is relatively close to our sun, at just 25 light-years away. It is also one of the most luminous stars in our galactic neighborhood.
"Vega is a white/blue star spectral type A0 V star, which means it's [got] a lot of blue in its spectrum," says Alexander. "Blue is quite easily visible to humans in the night sky so that probably helps us to see it as a much brighter star too."
Finally, our perspective on Vega helps us see it more brightly: "Vega is much hotter at its poles than its equator," explains Alexander. "We see it as 'pole' wards — that is one of its poles is pointing toward us. That'll add an element to why it's brighter."
2. It's a Also Big One
Vega is a massive star, about twice as large as our own sun. While size has relatively little impact on how bright stars appear to us due to the massive scale of distances in space, Vega's size, proximity and distance all come together to make it one of the brightest stars we can see.
3. It's the Once and Future North Pole Star
Vega is also special because it used to be the North Pole star around 12000 B.C.E. and will be again around the year 13727. Astronomers have studied changes in Earth's axial tilt (also called axial precession) to determine that Polaris has not always been the pole star — but Vega was once and will be again.
4. You've Seen Likely Vega Without Knowing It
Vega is visible to the unaided eye; in fact, you've probably already seen it without realizing it. For most people stargazing in the Northern Hemisphere, Vega is visible all night long and every night of the year. Further south, you might only see Vega in the summer months when it forms the "Summer Triangle" asterism with other bright stars Altair and Deneb.
To spot Vega in the night sky, you might not be able to pick out the constellation Lyra that it is part of. Instead, look for the cross formed by stars in the constellation Cygnus, the Swan. Vega is the bright star under one of the swan's "wing." Depending on the time of year and your latitude on Earth, you might see Cygnus directly overhead or in the northern part of the sky.
5. It Can Seem Dimmer
Vega has not dimmed significantly over the course of our celestial observation of it. "It seems pretty stable as stars go and only slightly variable," Alexander says. "I doubt it's been dimmer except for when it was a proto star about half a billion years ago."
However Vega does dim regularly because it is a variable star. That means its apparent magnitude changes in a predictable way due to the star's rotation. Vega's average magnitude is 0.03, but it ranges from −0.02-0.07; if you're curious why Vega's apparent magnitude is so close to zero, that's because British astronomer Norman Pogson used Vega as the baseline star to develop the magnitude scale for how bright stars appear to us!
6. It's a Young Star, Compared to Our Sun
Despite its massive size, astronomers calculate that Vega is only about one-tenth the age of our sun and is likely approaching middle age in its stellar life cycle. Given that our sun is roughly 4.5 billion years old, Vega is just 450 million years old and may only live another 450 million years. Our sun will still continue shining another 4 billion years after Vega has dimmed to a white dwarf.
7. Its Name Has Arabic Roots
Like many stars, Vega gets its name from the Arabic language. After all, many of the original ancient Greek astronomy documents were translated through Arabic to preserve them for modern astronomers.
According to Cyril Glassé in "The New Encyclopedia of Islam," Vega is likely a transliteration of the Arabic word "wāqi'", which means "falling" or "landing." It comes from the phrase an-nasr al-wāqi' which means "the falling eagle" and was documented in Al Achsasi al Mouakket, a star catalog published by Egyptian astronomer Muḥammad al-Akhṣāṣī al-Muwaqqit in the mid-17th century.
While we can't be certain, Vega's "name" was likely part of how Arabic astronomers placed Vega in their own system of constellations, similar to other Arabic star names and terms.
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Originally Published: Oct 23, 2020