# An Etymological Dictionary of Astronomy and AstrophysicsEnglish-French-Persian

## فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

### M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 9 Search : Balmer
 Balmer   بالمر   BâlmerFr.: Balmer   From Johann Jakob Balmer (1825-1898), Swiss mathematician and physicist, who explained the visible spectral lines of the hydrogen spectrum in 1885. Balmer continuum   پیوستار ِ بالمر   peyvastâr-e BâlmerFr.: continuum de Balmer   A continuous range of wavelengths in the Balmer spectrum of hydrogen corresponding to transitions between the energy levels n = 2 and n = ∞.→ Balmer; → continuum. Balmer decrement   کاهه‌ی ِ بالمر   kâhe-ye BâlmerFr.: décrément de Balmer   The intensity ratio among the couple of relatively adjacent → Balmer lines, for example Hα/Hβ and Hβ/Hγ, which have well-known theoretical values. They are used to determine the → interstellar extinction.→ Balmer; → decrement. Balmer discontinuity   ناپیوستگی ِ بالمر   nâpeyvastegi-ye BâlmerFr.: discontinuité de Balmer   An abrupt decrease in the intensity of the continuum at the limit of the → Balmer series of hydrogen (at about 3650 Å), caused by the energy absorbed when electrons originally in the second → energy level are ionized. Same as → Balmer jump.→ Balmer; → discontinuity. Balmer formula   دیسول ِ بالمر   disul-e BâlmerFr.: formule de Balmer   A special solution of the mathematical formula which represents the wavelengths of the various spectral series of hydrogen in which the lower energy level is n = 2.→ Balmer; → formula. Balmer jump   جهش ِ بالمر   jaheš-e BâlmerFr.: saut de Balmer   Same as → Balmer discontinuity.→ Balmer; → jump. Balmer limit   حد ِ بالمر   hadd-e BâlmerFr.: limite de Balmer   The wavelength in the blue end of the → Balmer series, at 3646 Å, near which the separation between successive lines decreases and approaches a → continuum.→ Balmer; → limit. Balmer line   خط ِ بالمر   xatt-e BâlmerFr.: raies de Balmer   The → spectral lines making up the → Balmer series.→ Balmer; → line. Balmer series   سری ِ بالمر   seri-ye Bâlmer (#)Fr.: série de Balmer   A series of hydrogen → spectral lines (Hα, Hβ, Hγ, and others) that lies in the visible portion of the spectrum and results when electrons from upper → energy levels (n > 2) undergo → transition to n = 2. Historically, Balmer emission lines (mainly Hα) from ionized nebulae were first observed by O. Struve and C. T. Elvey (1938, ApJ 88, 364). This was an important indication of the existence of hydrogen, in the ionized state, in the → interstellar medium.→ Balmer; → series.