Red, white and blue stars shine like sparklers being waved on a dark night in this new image from NASA’s Hubble Space Telescope. NASA released this image to celebrate the 250th anniversary of the United States, as the agency continues America’s legacy of exploration.
Located in the outer halo of our galaxy, the globular cluster NGC 6426 is a globular collection of stars held together by their mutual gravity, one of 150 known globular clusters in our galaxy. These clusters of stars are thought to form as a single unit from the same collapsing cloud of gas, and thus the stars in them are generally similar in age. Stars in globular clusters are ancient. At approximately 13 billion years old, NGC 6426 is one of the oldest globular clusters in the galaxy and is almost as old as the universe itself (13.7 billion years).
In this image, blue reflects shorter wavelengths of visible light, while red reflects longer wavelengths of visible light as well as some near-infrared light. The colors in Hubble images are chosen based on standard image processing techniques to best represent the wavelengths of light passing through the filters used in the observation. Since the color and temperature of stars are directly related, we know that in this image the blue stars are hotter and the red stars are cooler.
The stars of NGC 6426 have low metallicity, meaning they contain less elements heavier than hydrogen and helium. These conditions resemble those in the early universe, when matter was mostly helium and hydrogen and heavier elements were just beginning to form through nuclear fusion within massive stars.
Researchers have found evidence of two chemically distinct populations of stars in NGC 6426, indicating that the slightly younger and more metallic stars were enriched with material derived from the explosive deaths of earlier stars in the cluster. Massive stars that explode as supernovae throw elements heavier than hydrogen and helium into the universe, seeding the material for the formation of new stars and planets.
Hubble took this image as part of a study of globular clusters in the galaxy’s halo, with the aim of determining their age and shedding light on the formation and evolution of the galaxy. Over the past three decades in orbit, Hubble has fundamentally changed our understanding of the universe. Its discoveries have been extended and complemented by observations from other NASA missions, such as the infrared-detecting James Webb Space Telescope and the Nancy Grace Roman Space Telescope, which are scheduled to launch in late summer.
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media Contact: :
Claire Andreoli
NASA’s Goddard Space Flight Center, Greenbelt, MD
claire.andreoli@nasa.gov
