“The observations should shed light on the relation between age and composition in the Milky Way’s innermost globular clusters, comparable to our understanding of the clusters spread throughout the rest of our Galaxy.“Understanding the distribution of this hot plasma in space and time, as well as its dynamical motion, will shed light on diverse phenomena such as black holes, the evolution of chemical elements in the universe and the formation of galactic clusters,” Alexander said.Īlso aboard the latest Japanese rocket is the Smart Lander for Investigating Moon, or SLIM, a lightweight lunar lander. “The reddening of stars usually poses problems for astronomers, we were able to sidestep the effect of gas and dust by comparing the new observations made with the razor-sharp vision of Hubble’s Advanced Camera for Surveys (ACS) and Wide-Field Camera 3 (WFC3) with pre-existing images.” “The very brightest hot, blue stars are also along the line of sight and not inside the cluster, which only contains aging stars.” Only a few may actually be members of the cluster.” “The brightest red stars are bloated, aging giants, many times larger than our Sun. “Some of the stars in the photo of Terzan 12 appear starkly different in color to their near neighbors,” the astronomers said. Terzan attempted to fix his mistake, but the confusion caused has persisted in scientific studies ever since, astronomers eventually settling on the odd convention that there is no Terzan 11. The mix-up results from an error made by Terzan in 1971, when he rediscovered Terzan 5 - a cluster he had already discovered and reported in 1968 - and named it Terzan 11. There were actually only 11 clusters discovered by Terzan. The cluster was discovered by the Turkish-Armenian astronomer Agop Terzan approximately a half-century ago. Terzan 12, also known as ESO 522-1, is located about 15,000 light-years away in the constellation of Sagittarius. “The more dust that lies along our line of sight to the cluster, the more the light of the stars is reddened.” “Relatively unobscured stars shine brightly in white and blue, whereas creeping tendrils of gas and dust blanket other large portions of Terzan 12, giving stars a sinister red hue.” “We refer to the color change caused by the scattering and absorption of starlight as reddening, and it is responsible for the vibrant range of colors in the new image of Terzan 12.” “This means that the blue wavelengths of light from stars are less likely to make it through a cloud, making background stars appear redder than they actually are.” “The strength of this scattering depends on the wavelength of the light, with shorter wavelengths being scattered and absorbed more strongly.” “When starlight passes through an interstellar cloud it can be absorbed and scattered by particles of dust,” they said. “However, examining clusters like Terzan 12, highly obscured by interstellar dust, is complicated by the resulting reddening of the light.” “Around 150 are known, mostly in its outer halo, and Hubble has revolutionized their study since its launch in 1990.” “Globular clusters are not uncommon in the Milky Way,” Hubble astronomers said. Our own Milky Way Galaxy hosts at least 150 globular clusters and a few more are likely to exist hidden behind the Galaxy’s thick disk. They are among the oldest known objects in the Universe and are relics of the first epochs of galaxy formation. The word globulus, from which these clusters take their name, is Latin for small sphere. 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. This Hubble image shows Terzan 12, a globular cluster some 15,000 light-years away in the constellation of Sagittarius.
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