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

A fictitious name used by an author to conceal his or her identity; pen name (Dictionary.com).

→ pseudo-; → name.

→ Ptolemaic system.

→ Ptolemaic system; → astronomy.

The collective opinion of many people on some issue, problem, etc., especially as a guide to action, decision, or the like (Dictionary.com).

→ public; → opinion.

1) The act of publishing a book, periodical, map, piece of music, engraving, or the like.
2) The act of bringing before the public; announcement.
3) The state or fact of being published (Dictionary.com).

Verbal noun of → publish.

The act of pulsating; beating or throbbing; vibration or undulation. → stellar pulsation.

Verbal noun of → pulse.

The way in which pulsations occur in a star due to the fact that stars act as resonant cavities, as studied in → asteroseismology. A star may pulsate either with approximately spherical symmetry (radial pulsation), or as a series of waves running across the surface (non-radial pulsation). Pulsation may occur in a single mode or in multiple modes, depending on the type of star. Three different modes of pulsations have been detected through the → helioseismology of the → Sun: → p mode, → g mode, and → f mode, generated by acoustic, gravity, and surface gravity waves respectively. Also called → oscillation mode.

→ pulsation; → mode.

Of or pertaining to → pulsation. → pulsational instability; → pulsational pair-instability supernova.

→ pulsation; → -al

A term used to describe irregularly spaced, fine-scale structure in optically thick rings. The process relies on a combination of viscosity and self-gravity of ring material to produce this fine structure. Also known as overstability (Ellis et al., 2007, Planetary Ring Systems, Springer).

→ pulsational; → instability.

A → supernova resulting from the → pair instability that generates several successive explosions. According to models, a first pulse ejects many solar masses of hydrogen layers as a shell. After the first explosion, the remaining core contracts and searches for a stable burning state. When the next explosion occurs a few years later, several solar masses of material are again ejected, which collide with the earlier ejecta. This collision can radiate 10⁵⁰ erg of light, about a factor of ten more than an ordinary → core-collapse supernova. After each pulse, the remaining core contracts, radiates neutrinos and light, and searches again for a stable burning state. Later ejections have lower mass, but have higher energy. They quickly catch up with the first shell, where the collision dissipates most of their kinetic energy as radiation. The first SNe from → Population III stars are likely due to pulsational pair instability (Woosley et al. 2007, Nature 450, 390). See also → pair-instability supernova.

→ pulsational; → pair; → instability.

A nuclear reaction that takes place at high densities and relatively low temperatures. Pycnonuclear reactions are almost temperature independent and occur even at zero temperature. These reactions are extremely slow at densities typical for normal stars but intensify with increasing density. For example, carbon burns into heavier elements at densities over 10¹⁰ g cm^-3.

Pycnonuclear, from pycno- a combining form meaning "dense, thick," from Gk. pyknos "dense, solid" + → nuclear; → reaction.

Vâžireš, → reaction; cagâl-hasteyi, from cagâl, → dense, + hasteyi, → nuclear.

An equation with the general form of ax² + bx +c = 0, in which the highest power of the unknown is the second power (square).

→ quadratic; → equation.

1) A quality, accomplishment, etc., that fits a person for some function, office, or the like.
2) A circumstance or condition required by law or custom for getting, having, or exercising a right, holding an office, or the like.
3) The act of qualifying; state of being qualified (Dictionary.com).

→ qualify; → -tion.

The fact or process of quantifying.

Verbal noun of → quantify.

1) The procedure of restricting a continuous quantity to certain discrete values.
2) Physics: The procedure of deriving the quantum-mechanical laws of a system from its corresponding classical laws.

Verbal noun of → quantize.

The temporary variation in a → quantum field due to the → uncertainty principle.

→ quantum; → fluctuation.

The science concerned with the transmission, storage, and processing of information using quantum mechanical systems. It exploits the notion of → quantum entanglement between systems and joins several fields of knowledge, mainly quantum physics, information, computation, and probability.

→ quantum; → information.

Since → Planck's constant has the dimension of → energy × → time, its sometimes called the quantum of → action.

→ quantum; → action.

A phase transitions that occurs at zero temperature as a function of a non-thermal parameter like → pressure, → magnetic field, or → chemical composition. In contrast to ordinary → phase transitions, which are associated with passage through a critical temperature, quantum phase transitions are associated with → quantum fluctuations, a consequence of → Heisenberg's uncertainty principle. For example, see → Bose-Einstein condensation.

→ quantum; → phase; → transition.

The phenomenon wherein the → quarks are permanently bound together and can never be removed from the → hadrons they compose.

→ quark; → confinement.

A phase transition, predicted by cosmological models, to have occurred at approximately 10^-5 seconds after the Big Bang to convert a plasma of free quarks and gluons into hadron.

→ quark; → hadron; → phase; → transition.