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

Of, relating to, used in, or produced by means of chemistry.

From chemic "of alchemy," → chemistry + → -al.

Šimiyâyi, of or pertaining to šimi→ chemistry.
Šimik, from šim- + -ik, → -ic.

The relative amount of a given → chemical element or → chemical compound with respect to another element or compound in a given sample.

→ chemical; → abundance.

Same as → chemisorption.

→ chemical; → adsorption.

The extent to which a chemical species, such as an atom or molecule, tends to combine with another to form a chemical compound.

→ chemical; → affinity.

A force by which chemical substances are held together by attraction of atoms to each other through sharing, as well as exchanging, of electrons.

→ chemical; → bond.

The identities, and relative abundances of the → chemical elements or → compounds that make up a substance.

→ chemical; → composition.

A substance whose molecules are made up of atoms of at least two different elements.

→ chemical; → compound.

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.

→ chemical; → element.

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.

→ chemical; → enrichment.

The symbolic representation of a chemical reaction where the formulae of the → reactants are placed on the left and the formulae of → products on the right of an arrow.

→ chemical; → equation.

A cumulative change in the chemical properties, or more specifically, the relative abundances of chemical elements in an astrophysical system.

→ chemical; → evolution.

→ mixing process.

→ chemical; → mixing.

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.

→ chemical; → potential.

A → change or → transformation in which a → substance → decomposes, → combines with other → substances, or interchanges constituents with other substances.

→ chemical; → reaction.

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.

→ chemical; → separation.

A set of chemically → identical  → atomic or → molecular entities.

→ chemical; → species.

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).
See also → Ap/Bp stars.

→ chemical; → -ly; → peculiar; → star.

Of or relating to → geochemistry.

→ geochemistry; → -al.