GEMINI: Far From Home: Wayward Cluster is Tiny and Distant

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GEMINI: Far From Home: Wayward Cluster is Tiny and Distant

Post by bystander » Tue Mar 03, 2015 9:53 pm

Far From Home: Wayward Cluster is Both Tiny and Distant
Gemini Observatory | 2015 Mar 03
Like the lost little puppy that wanders too far from home, astronomers have found an unusually small and distant group of stars that seems oddly out of place. The cluster, made of only a handful of stars, is located far away, in the Milky Way’s “suburbs.” It is located where astronomers have never spotted such a small cluster of stars before.

The new star cluster was discovered by Dongwon Kim, a PhD student at the Australian National University (ANU), together with a team of astronomers (Helmut Jerjen, Antonino Milone, Dougal Mackey, and Gary Da Costa) who are conducting the Stromlo Milky Way Satellite Survey* at ANU. ...

The team’s first evidence of the unusually remote star cluster came when they ran detection algorithms on a 500 square-degree imaging data field obtained with DECam. “Such objects are too faint and optically elusive to be seen by eye. The cluster stars are sprinkled so thinly over the image, you look right through them without noticing (see image on electronic release, URL above). They are hiding in the sea of stars from the Milky Way. Sophisticated computer programs are our tools to find them,” said Jerjen.

Because it is so faint, ultra-deep follow-up observations using the Gemini Multi-Object Spectrograph (in imaging mode) confirmed that the new globular cluster is among the faintest Milky Way globular clusters ever found. Seven out of 150 known Milky Way globular clusters are comparably faint but none are located as far out toward the edge of the Milky Way. This new globular cluster has 10-20 times fewer stars than any of the other outer halo globular clusters. Also, its star density is less than half of that of other Milky Way globular clusters in the same luminosity (brightness) range. ...

Discovery of a Faint Outer Halo Milky Way Star Cluster in the Southern Sky - Dongwon Kim et al
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
— Garrison Keillor

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