StarDate

Morning Trio


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An astronomical trio lines up low in the east at first light tomorrow. Two of its members are easy to pick out: Venus, the brilliant “morning star,” with the true star Aldebaran close to its right. But to see the third member, you need to pull out your binoculars.

NGC 1647 is just to the right of Venus, much closer than Aldebaran is. It’s a star cluster – a tightly packed family of hundreds of stars. Most of the cluster’s details are a bit fuzzy, though. Estimates of its age, distance, and the number of stars vary by quite a bit.

In part, that’s because the cluster is behind a cloud of dust, which absorbs some of its light. But it’s also because NGC 1647 hasn’t received a lot of attention.

Measurements put the cluster’s distance at about 1800 to 2,000 light-years. One study said the cluster has at least 600 member stars, while another puts the number at 1300 or more. And estimates of its age range from about 120 million years to more than 260 million.

Based on the structure of NGC 1647, it appears that no matter how old it is, it may not last much longer. The cluster may be losing its grip on the stars outside its dense core. The stars are being pulled away by the gravitational tug of the rest of the galaxy. Soon, many of them could drift away – leaving a much smaller family of stars.

Tomorrow: shaking hands.

Script by Damond Benningfield

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StarDateBy Billy Henry