(ORDO NEWS) — On January 11, at the 241st meeting of the American Astronomical Society in Seattle, a team of researchers led by scientists from the University of Washington and the Center for Computational Astrophysics presented results from the Panchromatic Hubble Andromeda Treasury Triangulum Extended Region (PHATTER).
Astrophysicists have tried for the first time to examine in detail the various populations of stars that make up the Triangulum galaxy.
The researchers found that this galaxy has two dramatically different stellar structures. The triangle, which is about 61,000 light-years across, is the third largest galaxy in our local group.
In lower resolution images, the Triangle has a “flaky” structure with many small spiral arms radiating from a well-defined center.
For the PHATTER study, the Hubble Space Telescope took hundreds of images from various parts of the Triangulum galaxy.
The team combined smaller cross-section images to form a comprehensive, high-resolution dataset that showed individual stars at the center of a galaxy for the first time.
Thanks to Hubble’s many filters, the researchers were also able to separate these stars by age.
The distribution of young massive stars, less than 1 billion years old, roughly matched the “flaky” pattern that Triangulum is famous for.
But its older, redder stars are distributed quite differently: they form two spiral arms radiating from a rectangular band at the center of the galaxy.
Older stars make up most of Triangulum’s mass, but they are dimmer than their younger counterparts. This could explain why low-resolution images of the galaxy are dominated by a “flaky” pattern.
The research team also doesn’t know why young and old stars have such a divergent distribution in Triangulum.
Satellite galaxies as a whole are an eclectic group, and many questions remain about their formation and evolution.
Satellite galaxies come in a wide variety of shapes and can form as a result of interactions with their host galaxies.
For example, the largest satellite galaxy of the Milky Way, the Large Magellanic Cloud, is similar in size and mass to Triangulum, but has an irregular shape due to its proximity to our galaxy.
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