9 lines
997 B
Markdown
9 lines
997 B
Markdown
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name: δ Cephei
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constellation: Cep
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created_by: 8mag
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created_date: 2022-01-21 17:00:00
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updated_by: skybber
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updated_date: 2022-01-23 13:38:36.225114
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---
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together with the stars ε (4.19mag) and ζ Cep (3.35mag) form a small triangle. While these two stars are constant, δ Cephei changes its brightness periodically due to pulsations. In fact, a whole group of variable stars - the delta Cepheids - is named after this star. The variability of δ Cephei was discovered in 1784 by 20-year-old John Goodrick, a deaf-mute English amateur astronomer of Dutch origin (he discovered three variable stars, was the first to thoroughly investigate the changes in the brightness of Algol, and explained them correctly at the age of 19; he died two years later at the age of 21). At its brightest, the star reaches 3.48mag, while at its minimum it is 4.37mag, so these changes are easy to observe with the naked eye. Its period is 5.37 days. Cepheids are used by astronomers to estimate distances in space. |