šimiyâyi (#), šimik
Of, relating to, used in, or produced by means of chemistry.
farâvâni-ye šimiyâyi (#)
Fr.: abondance chimique
Fr.: adsorption chimique
Same as → chemisorption.
band-e šimik, ~ šimiyâyi
Fr.: liaison chimique
A force by which chemical substances are held together by attraction of atoms to each other through sharing, as well as exchanging, of electrons.
Fr.: composition chimique
Fr.: composé chimique
A substance whose molecules are made up of atoms of at least two different elements.
bonpâr-e šimiyâyi (#), onsor-e ~ (#)
Fr.: élément chimique
A substance which consists entirely of atoms of the same → atomic number and cannot be decomposed or changed into another substance using chemical means. Currently 118 chemical elements are known, the most abundant being → hydrogen. → periodic table.
Fr.: enrichissement chimique
The → process by which the relative → abundance of a given → chemical element or → species in an → astrophysical object is increased. For example the the → increase of the → heavy element content of the → interstellar medium due to → stellar evolution.
Fr.: équation chimique
fargašt-e šimiyâyi (#)
Fr.: évolution chimique
A cumulative change in the chemical properties, or more specifically, the relative abundances of chemical elements in an astrophysical system.
âmizeš-e šimiyâyi, ~ šimik
Fr.: mélange chimique
Fr.: potentiel chimique
For a given component in a → gas mixture, the change in → Gibbs free energy (G) with respect to change in amount of the component (n), when pressure, temperature, and amounts of other components remain constant: ∂G/∂n. Components are in equilibrium if their chemical potentials are equal.
vâžireš-e šimiyâyi, vâkoneš-e ~
Fr.: réaction chimique
Fr.: séparation chimique
The physical processes that can cause certain elements to migrate in a → stellar atmosphere. These processes are thought to be important in creating the chemical peculiarities seen in → Am stars and → Ap stars.
Fr.: espèce chimiique
chemically peculiar star
setâre-ye šimikâné afd
Fr.: étoile chimiquement particulière
A → main sequence star of
→ spectral type A or B
(→ A-type star, → B-type star)
identified by the presence of anomalously strong or weak
→ absorption lines of certain elements
in their spectra.
CP stars have been divided into four main classes on the basis of their
spectra: 1) non-magnetic metallic-lined (CP1,
→ Am star), magnetic (CP2,
→ Ap star), non-magnetic mercury-manganese (CP3,
→ HgMn star), and
helium-weak (CP4, → He-weak star).