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The Pleiades (M45) – Open star cluster
Image: NASA, ESA, AURA/Caltech, Palomar Observatory The science team consists of: D. So · Public domain
✨ Star clusters · Star Nurseries & Graveyards

The Pleiades (M45)

Open star cluster

The Pleiades are a family of young, hot, blue stars that were born together. Six or seven are visible to the eye, but there are more than a thousand. The blue haze around them is a dust cloud they are passing through.

  • 444 light-years awayEven light – the fastest thing there is – needs 444 years to get here.
  • ~100 million yearsAge
  • 1,000+Stars
🔭 Find it in the sky

Take a closer look

Names from a myth

In Greek myth the Pleiades were seven sisters, daughters of the giant Atlas and the sea nymph Pleione. Their parents are in the cluster too, as two of its brightest stars. The brightest of all is Alcyone, a blue giant at the centre of the little dipper shape.

The distance puzzle

In the 1990s the Hipparcos satellite measured the Pleiades as about 390 light-years away, closer than other methods suggested. Scientists argued about it for years. Later measurements, including from the Gaia spacecraft, settled on about 444 light-years – showing why astronomers check results in more than one way.

A family that will scatter

The Pleiades stars were born together, but they won’t stay together forever. The gravity of passing stars and clouds slowly tugs them apart, and in a few hundred million years the family will have scattered. Our Sun was probably born in a cluster too, with long-lost sibling stars.

How we found out

  1. ~1600 BC

    The Nebra sky disc, found in Germany, may show the Pleiades – one of the oldest known images of the sky.

  2. 1610

    Galileo turns his telescope on them and counts dozens of stars.

  3. Around the world

    In Japan they’re Subaru (the car company’s logo shows them). In India they’re Krittika. For Māori people, their rising (Matariki) marks the New Year.

🤔 Something to wonder about

Why do so many cultures have a story about “seven sisters”?

See it yourself

A tiny, misty “mini-dipper” of stars. Follow Orion’s belt up and to the right past the orange star Aldebaran.

Got it?

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