The Real Distance to the Pleiades: Astronomers Settle Controversy about Famous Star Cluster

Astronomers may have solved a longstanding controversy when it comes to the Pleiades, a famous star cluster. They've accurately measured the distance from our planet to the star cluster, which may correct models of star formation.

The Pleiades is also known as the "Seven Sisters" star cluster, and is located in the constellation Taurus. It can easily be seen in the winter sky, and includes hundreds of young, hot stars that formed about 100 million years ago. Because Pleiades is a good example of a young cluster, it's served as a natural laboratory when it comes to understanding how similar clusters form.

In the past, researchers believed that the Pleiades were about 430 light-years from Earth. Yet then new research indicated that the distance was only about 390 light-years.

"That may not seem like a huge difference but, in order to fit the physical characteristics of the Pleiades stars, it challenged our general understanding of how stars form and evolve," said Carl Melis, one of the researchers, in a news release. "To fit the Hipparcos distance measurement, some astronomers even suggested that some type of new and unknown physics had to be at work in such young stars."

That's why the researchers decided to measure the distance once more. They used a global network of radio telescopes to make the most accurate possible distance measurement. They observed several Pleiades stars over about a year and a half in order to make these precise measurements and examine the apparent shift in each star's position caused by the Earth's rotation around the sun.

So what did they find? It turns out that the distance to Pleiades is 443 light-years, which is accurate to within one percent. This precise measurement gives researchers the information they need in order to work on future models.

The findings are published in the journal Science.