The new image taken with the NASA/ESA Hubble Space Telescope provides a detailed look at Terzan 2, a globular cluster located in the constellation of Scorpius.
This Hubble image shows the globular cluster Terzan 2. Image credit: NASA / ESA / Hubble / R. Cohen.
Globular clusters are stable, densely packed collections of hundreds of thousands or even millions of stars, gravitationally bound into a single structure about 100-200 light-years across.
The word globulus, from which these clusters take their name, is Latin for small sphere.
Globular clusters are among the oldest known objects in the Universe and are relics of the first epochs of galaxy formation.
Our own Milky Way Galaxy hosts at least 150 such objects and a few more are likely to exist hidden behind the Galaxy’s thick disk.
“The intense gravitational attraction between the closely packed stars gives globular clusters a regular, spherical shape,” Hubble astronomers said.
“As a result, images of the hearts of globular clusters, such as this observation of Terzan 2, are crowded with a multitude of glittering stars.”
Also known as ESO 454-29 and Haute-Provence 3, Terzan 2 is located in the constellation of Scorpius.
The object is one of a dozen globular clusters discovered by the French astronomer Agop Terzan in the 1960s-70s.
The new image of Terzan 2 is made up of observations from Hubble’s Advanced Camera for Surveys (ACS) and Wide Field Camera 3 (WFC3) instruments in the infrared and optical parts of the spectrum.
“Despite having only one primary mirror, Hubble’s design allows multiple instruments to be used to inspect astronomical objects,” the researchers explained.
“Light from distant astronomical objects enters Hubble and is collected by the telescope’s 2.4-m primary mirror.”
“It is then reflected off the secondary mirror into the depths of the telescope, where smaller mirrors can direct light into individual instruments.”
“Each of the four operational instruments on Hubble is a masterpiece of astronomical engineering in its own right, and contains an intricate array of mirrors and other optical elements to remove any aberrations or optical imperfections from observations, as well as filters which allow astronomers to observe specific wavelength ranges.”
“The mirrors inside each instrument also correct for the slight imperfection of Hubble’s primary mirror.”
“The end result is a crystal-clear observation, such as this glittering portrait of Terzan 2.”
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