Astronomers using the NASA/ESA Hubble Space Telescope have produced an outstanding image of the bulge globular cluster NGC 6540.
NGC 6540 is a globular cluster about 17,000 light-years away in the constellation of Sagittarius.
“The populations of globular clusters can range from tens of thousands to millions of stars, all of which are trapped in a closely-packed group by their mutual gravitational attraction,” Hubble astronomers said.
“The brightest stars in this image of NGC 6540 are adorned with prominent cross-shaped patterns of light known as diffraction spikes.”
“These astronomical embellishments are a type of imaging artifact, meaning that they are caused by the structure of Hubble rather than the stars themselves.”
“The path taken by the starlight as it enters the telescope is slightly disturbed by its internal structure, causing bright objects to be surrounded by spikes of light.”
NGC 6540 was discovered by the German-born British astronomer Wilhelm Herschel on May 24, 1784, who described the star cluster as ‘pretty faint, not large, crookedly extended, easily resolvable.’
Also known as C 1803-278 or Djorg 3, the cluster has a core diameter of 10 light-years.
NGC 6569 is located in the Galactic bulge, a massive and dense region of stars at the heart of our Milky Way Galaxy.
“Hubble peered into the heart of NGC 6540 to help us measure the ages, shapes, and structures of globular clusters towards the center of the Milky Way,” the researchers explained.
“The gas and dust shrouding the center of our Galaxy block some of the light from these clusters, as well as subtly changing the colors of their stars.”
“Globular clusters contain insights into the earliest history of the Milky Way, and so studying them can help astronomers understand how our galaxy has evolved.”
The color image of NGC 6540 is made up of observations from Hubble’s Advanced Camera for Surveys (ACS) and Wide Field Camera 3 (WCF3).
“These two instruments have slightly different fields of view — which determines how large an area of sky each instrument captures,” the scientists said.
“This composite image shows the star-studded area of sky that was captured in both instruments’ field of view.”
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