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Using data from the Two Micron All-Sky Survey (2MASS), we identify a population of infrared carbon (IR C) stars with J-K >= 2 in the Milky Way. These stars are shown to trace the stellar bar previously identified in IR and optical surveys. The properties of C stars strongly suggest that they are of intermediate age. We conclude that the bar is likely to have formed more recently than 3 Gyr ago, and must be younger than 6 Gyr. Implications and further tests of this conclusion are briefly discussed.

生成讲解博客的中文版本

生成AI智能校验的中文版本