University of Arizona | 2018 Nov 07
The way they move belies the true ages of the almost 3,000 stars populating one of the richest star clusters known. Astronomers recently discovered the stars all were born in the same generation, solving a long-standing puzzle about how stars evolve.
Do star clusters harbor many generations of stars or just one? Scientists have long searched for an answer and, thanks to the University of Arizona’s MMT telescope, found one in the Wild Duck Cluster, where stars spin at different speeds, disguising their common age.
- An image of the Wild Duck Cluster (M11) was captured by the MPG/ESO 2.2-metre telescope at the La Silla Observatory in Chile. The blue stars at the center of the image are the stars of the cluster. Every star in the Wild Duck Cluster is roughly 250 million years old. Older, redder stars surround the cluster. (Credit: ESO)
In a partnership between the UA and the Korean Astronomy and Space Science Institute, a team of Korean and Belgian astronomers used UA instruments to solve a puzzle about flocks of stars called open clusters.
Astronomers have long believed that many open clusters consist of a single generation of stars because once stars have formed, their radiation blows away nearby material needed to make new stars. But in the Wild Duck Cluster – known by scientists as Messier 11, or M11 – stars of the same brightness appear in different colors, suggesting they are of different ages. Unless scientists had missed important clues about stellar evolution, there had to be another explanation for the spread of colors in this accumulation of about 2,900 stars. ...
The stars in the Wild Duck Cluster, it turns out, are spread out in the color spectrum not because of different ages, but because of different rotational periods. ...
Extended Main Sequence Turn-off Originating from a Broad Range of Stellar Rotational Velocities ~ Beomdu Lim et al