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

1) The most commonly used definition is temperature of 273.15 K (0 °C) and pressure of 1 → atmosphere.
2) Chemistry: Temperature of 273.15 K (0 °C) and pressure of 10⁵  → pascal (Pa)s (1 → bar). International Union of Pure and Applied Chemistry (IUPAC) recommends that the former use of the pressure of 1 atm as standard pressure (equivalent to 1.01325 × 10⁵ Pa) should be discontinued.

→ standard; → temperature; → pressure.

The time in any of the 24 internationally agreed time zones into which the Earth's surface is divided. The primary zone is centered on the Greenwich meridian (0° longitude).

→ standard; → time.

Photometric values of selected stars in a standard system.

→ standard; → value.

A wave produced by the simultaneous transmission of two similar wave motions in opposite directions. Same as stationary wave.

Standing verbal adjective from stand, cognate with Pers. istâdan, as below; → wave.

Istân pr.p. of istâdan "to stand;" Mid.Pers. êstâtan; O.Pers./Av. sta- "to stand, stand still; set;" Av. hištaiti; cf. Skt. sthâ- "to stand;" Gk. histemi "put, place, weigh," stasis "a standing still;" L. stare "to stand;" Lith. statau "place;" O.N. standa, Goth. standan, O.H.G. stantan, Swed. stå, Du. staan, Ger. stehen; O.E. standan; PIE base *sta- "to stand;" mowj, → wave.

A superluminous → Type Ia supernova which is characterized by a bright → light curve peak, a slow light curve evolution during the photospheric phase, and moderately low ejecta velocities. Modeling suggests ejecta masses far in excess of the → Chandrasekhar limit of mass for non-rotating → white dwarfs and the production of about 1.5 Msun of ⁵⁶Ni. This precludes the interpretation of these events as thermonuclear explosions of Chandrasekhar-mass white dwarfs.

→ super-; → Chandrasekhar limit.

A star which according to observational data could become a supernova.

→ supernova; → candidate.

One of the three prominent bands in the spectra of comets and carbon stars caused by diatomic carbon (C₂).

Named after the Scottish physicist William Swan (1818-1894) who first studied the spectral analysis of radical carbon C₂ in 1856; → band.

A band seen in the spectra of celestial objects, which is due to absorption by gases such as oxygen, water vapor, and carbon dioxide in the Earth's atmosphere

→ telluric; → band.

Any of the several → absorption bands due to the molecule → titanium oxide that are prominent in the spectra of cool → K and → M stars.

→ titanium oxide; → band.

In celestial mechanics, a combination of orbital elements commonly used to distinguish between comets and asteroids. Objects whose Tisserand's parameter value is smaller than 3 are considered to be dynamically cometary, and those with a value larger than 3 asteroidal. Also called Tisserand's invariant.

Named after François Félix Tisserand (1845-1896), French astronomer, Director of the Paris Observatory (1892).

A Belgian facility devoted to the detection and characterization of → exoplanets and to the study of → comets (→ transiting planet) and other → small solar system bodies. It consists of two 60 cm robotic telescopes located at the → European Southern Observatory, → La Silla, in Chile and at Oukaïmden Observatory in Marroco.

→ transit; → planet; → planetesimal; → small; → telescope.

The frequency range above the cutoff frequency in a waveguide or transmission line.

→ transmission; → band.

To perceive the meaning of.

M.E. understanden, understonden, O.E. understandan "comprehend, grasp the idea of," probably literally "to stand in the midst of," from → under- + standan "to stand," cognate with Pers. istâdan, → standard.

Fahmidan, from Ar. fahm + infinitive suffix -idan.

The ability to understand something; the → power of → abstract  → thought.

→ understand; → -ing.

A no longer in general use name for → Aromatic Infrared Band.

→ unidentified; → infrared; → band.

The range of energy states in the spectrum of a solid crystal which includes the energies of all the electrons binding the crystal together.

→ valence; → band.

A portion of the electromagnetic spectrum which is defined because of its characteristics or for its use.

→ wave; → band.

A sequence of → permitted transitions in the → ultraviolet from an → excited state (C) of the → molecular hydrogen (H₂) to the electronic → ground state, with ΔE > 12.3 eV and λ ranging from 1160 Å to 1250 Å. When a hydrogen molecule absorbs such a photon, it undergoes a transition from the ground electronic state to the excited state (C). The following rapid → decay creates an → absorption band in that wavelength range. See also → Lyman band; → Lyman-Werner photon.

Named after the Danish physicist Sven Theodor Werner (1898-1984), who discovered the band (S. Werner, 1926, Proc. R. Soc. London Ser. A, 113, 107); → band.

A spectral feature at 9850-10200 Å appearing in the spectrum of some late-type → M dwarfs. It is attributed to iron hybrid (FeH), a typical signature of the atmospheres of the coolest stars.

First detected by R. F. Wing and W. K. Ford (1969, PASP 81, 527); → band.

Any of the three → absorption bands due to the molecule → zirconium oxide present in the blue and visual spectral regions → S-type stars. The bands are centered on the wavelengths 4614, 5551, and 6468 Å.

→ zirconium oxide; → band.