An Etymological Dictionary of Astronomy and Astrophysics
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فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 6 Search : Cepheid
beat Cepheid
  کِفِیءوسی ِ زنشی   
kefeusi-ye zaneši

Fr.: céphéide à battement   

A Cepheid variable in which two or more almost identical periods of variability pass into and out of phase with each other, producing periodic amplitude fluctuations in their light curves. Beat periods are typically about 2 hours.

beat; → Cepheid.

bump Cepheid
  کِفِیءوسی ِ قوزدار، ~ زوکدار   
Kefeusi-ye quzâr, ~ zokdâr

Fr.: céphéide à bosse   

A subtype of classical → Cepheid variable stars that show a bump on the descending branch of their → light curve.

Bump "a relatively abrupt convexity or bulge on a surface," probably imitative of the sound of a blow; → Cepheid.

Quzdâr, from quz "hump," variant of kužconvex + -dâr "possessing," from dâštan "to have, possess." Zokdâr, from Lori zok "a raised spot, a bulge," cf. Northern Fârs Âbâdé dialect lok " swellimg, knob;" Kefeusi, → Cepheid.

Cepheid
  کفیءوسی   
Kefeusi

Fr.: céphéide   

A class of luminous, → yellow supergiants that are pulsating variables and whose period of variation is a function of their luminosity. These stars expand and contract at extremely regular periods, in the range 1-50 days. Their highest brightness and surface temperature occur when their expansion velocity is greatest. Similarly, their minima in brightness and temperature occur when they are in the contraction phase. The longer the period, the more luminous the star. In fact, Cepheids provide one of the most powerful tools for measuring distances to other galaxies (→ period-luminosity relation). However, this method is limited to the distance of the → Virgo cluster of galaxies (15-20 → Mpc) even with the → HST or the largest ground-based telescopes. One particularly special Cepheid is the North Star, → Polaris.

Named after the prototype → Delta Cephei discovered by John Goodricke in 1784. → Cepheus.

Cepheid variable
  ورتنده‌ی ِ کفیءوسی   
vartande-ye Kefeusi

Fr.: variable Céphée   

A → variable star belonging to the class of → Cepheids.

Cepheid; → variable.

dwarf Cepheid
  کفیءوسی ِ کوتوله   
Kefeusi-ye kutulé

Fr.: céphéide naine   

An old name for a class of pulsating variable stars with small variations in amplitude, also called an AI Velae star or delta Scuti star. They lie in the lower part of the Cepheid instability strip.

dwarf; → Cepheid.

ultrashort-period Cepheid
  کفیءوسی ِ اولتر-کوتاه-دوره   
Kefeid-e ultar-kutâh-dowré

Fr.: céphéide à très courte période   

A → Cepheid star of → spectral type A-F with regular pulsation period of 1-3 hours and with small variations in amplitude. This group is also known as δ Scuti stars.

ultra-; → short; → period; → Cepheid.