An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

1) A large piece of thick cloth for use as a bed covering, animal covering, etc, enabling a person or animal to retain natural body heat.
2) Any extended covering or layer (Dictionary.com).
→ blanketed model, → blanketing, → blanketing effect, → line blanketing, → line-blanketed model, → unblanketed model, → wind blanketing.

From M.E., from O.Fr. blanchet, diminutive of blanc "white; white cloth."

Patu "blanket; a kind of woolen cloth," Kermâni dialect poto "wollen; woolly;" cf. Skt. patta- "cloth, colored or fine cloth."

→ line blanketing.

→ line blanketing.

→ line blanketing.

In Dirac's notation, an expression which is a → scalar product of the dual vectors → bra and → ket which describe a quantum state. The bra vector appears on the left of the ket vector.

From M.Fr. braguette "codpiece armor."

A series of lines in the infrared spectrum of atomic hydrogen due to electron jumps between the fourth and higher energy levels (Br α has wavelength 4.052 μm, Br γ 2.166 μm).

Named after the American physicist Frederick Brackett (1896-1980); → series.

Of an → impact crater, the ejecta that after the → impact event settles back to the Earth's surface. The ejecta blanket is thick near the → crater rim and thin outward from the crater.

→ ejecta; → blanket.

In Dirac's notation, a vector which describes the state of a quantum system, whether it is in a space of finite or infinite dimensions. A ket vector, written as | A >, is the dual of the → bra. Like the bra, it appears as an incomplete → bracket expression.

From -ket the second syllable in → bracket.

In stellar atmosphere models, the effect of metallic lines on the atmospheric structure of stars. The additional opacities of thousands of metallic lines alter the radiative transfer, leading to changes in the temperature. The emergent spectrum is consequently modified.

→ line-blanketed model.

A stellar atmosphere model which includes metals or uses methods to reproduce their effects, → line blanketing.

→ line; → blanket; → model.

A → binary system consisting of two → massive stars, which are → supergiants of → spectral types O7.5 and O6. The two components are so close together that they orbit each other with a period of 14.4 days only. The Plaskett's star is a → double-line binary. The estimated masses of the components are 43 (Plaskett A) and 51 (Plaskett B) → solar masses. The lower mass component is optically brighter than the other star. Also known as HR 2422 and HD 47129 (See, e.g., Bagnuolo et al. 1992, ApJ 385, 708).

Named after the Canadian astronomer John S. Plaskett (1865-1941), who made a detailed spectroscopic study of this star in 1922.

A projectile driven by reaction propulsion that carries its own propellants. → missile = mušak (موشک).

From It. rocchetto "a rocket," literally "a bobbin," diminutive of rocca "a distaff," with reference to its shape.

The study of celestial bodies in the wavelengths that are almost completely absorbed by the atmosphere, by using a rocket to carry instruments above 250 km to measure the searched for phenomena.

→ rocket; → astronomy.

The science of rocket design, development, and flight.

→ rocket + -ry a noun suffix.

Roket šenâsi, from roket, → rocket, + šenâsi, → -logy; roketgari with suffix -gari, from -gar, → -or.

A stellar atmosphere model which ignores metals and their physical effects. → line-blanketed model; → line blanketing.

→ un-; → blanketed model.

A traveling → waveform consisting of the → superposition of several → waves of different → wavelengths and → phases.

→ wave; packet from M.E. pak "bundle" + diminutive suffix -et; maybe from M.Fr. pacquet.

Basté "packet," literally "bound, tied; set," p.p. of bastan "to form, bind, tie" (Mid.Pers. bastan/vastan "to bind, shut;" Av./O.Pers. band- "to bind, fetter," banda- "band, tie;" cf. Skt. bandh- "to bind, tie, fasten;" Ger. binden; E. bind; PIE base *bhendh- "to bind").

A process whereby dense winds of very luminous O type stars modify the temperature and internal structure of the underlying photosphere by scattering back a considerable part of the coming photospheric radiation. Not to be confused with → line blanketing .

Thus called because the wind acts like a blanket and heats the photosphere * by reflecting its radiation; → wind.