How far is Altair from Earth?

The twelfth brightest star in our solar system, Altair, is approximately 16.8 light years away from Earth, making it one of our nearest stellar neighbours.

Altair, also known as Alpha Aquilae, is the brightest star in the northern constellation, Aquila. It is also the twelfth brightest star in our solar system. Along with the bright stars, Vega and Deneb, Altair forms the renowned asterism of the Sumer Triangle. However, Altair is distinctive in its own right.

Altair (© NASA/JPL/Caltech/Steve Golden)

It is currently situated in the G-cloud, which is a nearby interstellar cloud. The cloud is an accumulation of dust and gas. Altair is an A-type, main-sequence star and it has an apparent visual magnitude of 0.77.

Scientists have discovered that Altair rotates very quickly, with a velocity at the equator of nearly 286 kilometres per second. However, it is only a fraction of the star’s estimated breakup speed of 400 kilometres per second.

A recent study with the Palomar Testbed Interferometer shows that Altair is not spherical. Due to its fast rotation, it has a flattened shape. Its equatorial diameter is approximately 20 percent larger than its polar diameter. Photographs taken in 2006 of Altair’s surface revealed that the fast rotation also causes the equator to be darker. Subsequently, it is cooler than the poles.

People will be able to spot Altair in the night sky quite easily, as it is only 16.8 light years away from Earth. This makes it one of our nearest stellar neighbours. People living in the Northern Hemisphere can view Altair during the months of July and August.

It is recommended that people search for the large Summer Triangle asterism in the east. Altair is the last of the three Summer Triangle stars to rise over the horizon.

Even though people can view Altair and its two companion stars with the naked eye, it is recommended that people use a telescope. This way, they will be able to adore Altair in its full glory.