R-type star

astronomy

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July 13, 2026

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R stars, also known as Type R stars, are a classification of red stars characterized by surface temperatures around 2,500 kelvins. These stars are part of a broader stellar classification system that categorizes stars based on their temperature, estimated from their spectra. The sequence of stellar types, from hottest to coolest, includes O, B, A, F, G, K, and M, with R, N (often called carbon stars), and S types supplementing this sequence. R stars, along with N and S types, differ in chemical composition and are typically giant or supergiant stars.123

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stellar classification
…classes of cool stars include R and N (often called C-type, or carbon stars: less than 3,000 K), and S, which resemble class M stars but have spectral bands of zirconium oxide prominent instead of those of titanium oxide.
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…classes of cool stars include R and N (often called C-type, or carbon stars: less than 3,000 K), and S, which resemble class M stars but have spectral bands of zirconium oxide prominent instead of those of titanium oxide.
Read More