Sigma Draconis

Sigma Draconis is a single star in the northern constellation of Draco. It is known by the proper name Alsafi. It shines with an apparent visual magnitude of 4.7. This makes it just visible to the naked eye on a clear night.

This quiet star is about 18.8 light years from the Sun. It is a relatively close neighbor in our cosmic neighborhood. Because it is one of the closer stars visible without a telescope, Sigma Draconis has been studied by astronomers for centuries.

The star’s name "Alsafi" comes from ancient Arabic astronomy. Over time, it was given the latinised name σ Draconis. It is often shortened to Sig Dra or σ Dra. This follows the Bayer designation system used to label stars in each constellation.

Scientists use parallax to measure its distance from us. Parallax is the apparent shift in a star’s position as Earth orbits the Sun. Currently, Sigma Draconis is moving away from the Sun at a radial velocity of 26.6 kilometers per second. This gentle drift through space helps us learn more about the star’s journey.

Name

σ Draconis (Latinised to Sigma Draconis) is the star's Bayer designation, named in 1603 in a book called the Uranometria.

The star is also known as Alsafi, a name that comes from an Arabic word. In 2016, a group called the Working Group on Star Names chose Alsafi as the official name. In Chinese, it is called 天廚二, which means "the Second Star of Celestial Kitchen."

Properties

Sigma Draconis is a small, ordinary star that you can see without a telescope. It is a little cooler and less bright than our Sun, and it spins slowly. Scientists have measured its size and found it to be a bit smaller than the Sun.

This star moves quickly across the sky and follows a path that takes it farther from the center of our Milky Way galaxy than the Sun does. So far, no large planets or disks of dust have been found around Sigma Draconis.

Search for planets

Scientists have looked for planets around Sigma Draconis using tools at the Keck Observatory and the Lick Observatory. From 2004 to 2013, they thought they saw signs of a planet about the size of Uranus orbiting the star every 308 days. But they need more proof to be sure.

In 2017, another study did not find a planet. It suggested the changes might be from the star’s magnetic activity. A newer study in 2025 found changes every 409.7 days. They think this is also from the star’s activity.