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单词 classical Cepheid
释义

classical Cepheid

Astronomy
noun
A Cepheid belonging to a subcategory typified by the star δ Cephei (also called type I Cepheids), used to establish a period–luminosity relation for stars with a similar variability pattern, which subcategory comprises population I stars typically having a period of 5–10 days (as contrasted with type II Cepheids, which are population II stars with generally longer periods and lower luminosity).
  • The Cepheid period–luminosity relation is used for determining extragalactic distances up to 15 megaparsecs (the Virgo Cluster)..

Origin

1920s.

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更新时间:2024/12/23 9:47:58