An Etymological Dictionary of Astronomy and Astrophysics
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A periodic change in one of the components of the orbit of a celestial object.

→ canonical; → change.

Any set of generalized coordinates of a system together with their → conjugate momenta.

→ canonical; → coordinates.

The highest correlation between linear functions of two data sets when specific restrictions are imposed upon them.

→ canonical; → correlation.

The most general form of an equation.

→ canonical; → equation.

The simplest expression of an equation, statement, or rule.

→ canonical; → form.

A two-component stellar → initial mass function with → slopes of 1.3 and 2.3 for massive and low mass stars, respectively. Also called universal IMF.

→ canonical; → IMF.

A model for the formation of the Moon according to which the → Moon results from a giant impact. A Mars-sized body (often referred to as → Theia) obliquely collided with the proto-Earth at the mutual escapee velocity. This specific giant impact is often used to represent all giant impacts. A recent advanced version of the canonical model is called → giant impact hypothesis.

→ canonical; → model.

Same as → conjugate momentum.

→ canonical; → momentum.

A physical upper mass limit near 150 Msun assumed for the stellar → initial mass function (Kroupa et al. 2012, arXiv:1112.3340).

→ canonical; → upper; → limit.

A generalized coordinate and its → conjugate momentum.

Canonically, adverb from → canonical; → conjugate; → variable.

The brightest star in the → constellation  → Carina and the second brightest star in the sky with a → visual magnitude -0.72. Also called α Carinae and HD45348. Canopus is not visible from latitudes above 37 degrees north. It is an evolved star, a → supergiant of type F0 II (Smiljanic et al., 2006, A&A 449, 655). Canopus lies 310 → light-years (96 → parsecs) from the Solar System; this is based on its → Hipparcos  → parallax measurement of 10.43 mas (5% accuracy). From this distance a → luminosity 13,300 times that the → solar luminosity is derived, and a radius of 73 times solar, in agreement with the → angular size (6.95 ± 0.15 mas) measured using → interferometry (Cruzalèbes et al., 2013, arXiv:1306.3288). These observations also yield an → effective temperature of about 7400 K. The star's mass is estimated to be about 8 Msun. Canopus possesses an extremely hot magnetically heated → corona. Canopus's corona is some 10 times hotter than the → solar corona and produces both observable → X-rays and → radio emission. According to calculations by J. Tomkin (1998, Sky & Telescope 95, 59), using → Hipparcos data, Canopus has, in the past, been the brightest star during three periods: from 3,700,000 to 1,370,000 years ago, from 950,000 to 420,000 years ago, and from 160,000 to 90,000 years ago. It will, once more, become the brightest star in 480,000 years and will remain such for 510,000 years.

Canopus, from Gk. kanobos, perhaps from Coptic language Kahi Nub "golden earth."

Soheyl, from Ar. Suhail.
Agast, either a loan from Skt., or a possible, vanished Av. counterpart of Skt. Agasti, Agastya. The Skt. word derives from aga- "mountain," and asti- "thrower." In Vedic literature, Canopus is associated with the sage Agastya, one of the ancient rishis. The star is said to be the "cleanser of waters" because of turbid waters becoming clean at its rising.
Parak, of unknown etymology.

1) A covering for the head.
2) The top part of something (such as a hill or mountain). → polar cap.
3) A removable cover or lid.

M.E. cappe; O.E. cæppe "hood, head-covering," from L.L. cappa "a cape, hooded cloak," possibly shortened from capitulare "headdress," from L. caput "head;" cf. Pers. Lori kapu "head," kapulek "skull, middle of the head;" Kurd. Kurmanji qaf "head;" Pashto kaparay "skull;" Farâhâni kapâl "a blow on the head."

Kolâhak, diminutive of kolâh "cap;" maybe related to PIE base *kel- "conceal;" cf. L. celare "to hide, conceal," occulere "to dissimulate;" Gk. kalyptein "to cover," kalia "hut, nest;" Skt. cala "hut, house;" Goth. hilms "helmet," huljan "cover over," hulistr "covering;" E. hull "seed covering," from O.E. hulu, from O.H.G. hulla, hulsa; O.E. hol "cave;"

The ratio of the charge Q on either conductor of a → capacitor to the → potential difference, or → voltage V between the conductors. It is given by C = Q/V. Capacitance can also be described by the relation: C = ε₀A/d, where ε₀ is the → permeability of free space, A is the area of one capacitor plate, and d is the distance between the capacitor plates. Capacitance is measured in → farads or, for convenience, in microfarads.

From capacit(y), → capacity + → -ance, a suffix used to form nouns either from adjectives in -ant or from verbs.

Gonjâyi, from gonjâ "able to hold," from gonjidan→ capacity + -yi noun suffix.

A device for storing electric charge. The simplest sort of capacitors consists of two parallel, conductive plates having equal amounts of opposite charges and separated by a → dielectric material. When a capacitor is fully charged there is a → potential difference between its plates. The larger the area of the plates and/or the smaller the separation between them the greater will be the charge that the capacitor can hold and the greater will be its → capacitance. The actual charge Q on the plates of a capacitor is given by: Q = C . V, where C is the capacitance and V the → voltage.

From capacit-, from → capacity + → -or.

From gonjân transitive stem of gonjidan "to be contained; to hold exactly; to be filled," → capacity, + -gar, → -or.

The ability to receive or contain.
Electricity: → capacitance.

From M.Fr. capacité, from L. capacitatem, from capax "able to hold much," from capere "to take, grasp."

Gonjâyeš "capacity, holding, containing," from gonjdan "to be contained; to hold exactly; to be filled;" Mid.Pers. winj- "to be contained;" Proto-Iranian *uiac-/*uic-; cf. Skt. vyac- "to contain, encompass," vyás- "extent, content, extension;" L. uincire "to bind."

The sixth brightest star in the sky, Capella lies in the Northern Hemisphere → constellation  → Auriga. Also known as HD 34029 = HR 1708 = HIP 24608. Capella lies about 42 → light-years away (13.159 ± 0.015 → parsecs). Its → apparent visual magnitude is V = 0.07. A → spectroscopic binary, it consists of a pair of G8 III and G0 III → giants with an → orbital period of 104 days. The more evolved former/→ primary star has a slightly larger mass and luminosity (2.6 Msun and 79 Lsun) than that of the latter/→ secondary star (2.5 Msun and 73 Lsun). The primary is a typical late G giant presumably in the He-burning stage (→ red clump), which is lithium deficient and a slow rotator as other normal giants. In contrast, the secondary is a fast rotator (projected rotational velocity is v_e sin i ~ 35 km s-1) with high stellar activity (characterized by conspicuous chromospheric emission lines in UV) and shows a remarkably strong Li line, which indicates that the initial Li content is almost retained without being diluted (the surface Li composition for the secondary is ~100 times higher than that for the primary). That is, the secondary star belongs to the unusual group of Li-rich giants (see, e.g., Takeda et al., 2018, ApJ 862, 57 and Torres et al., 2015, ApJ 807, 26).

From L. capella "little she-goat," diminutive of caper "goat."

Bozbân "goat keeper" (Biruni, A.D. 973-1048, in his Tafhim), from boz, → goat, + -bân prefix denoting "keeper."
Ayyuq, loan from Ar.

Same as → capillary action.

→ capillary; → -ity.

1) Resembling a strand of hair; hairlike.
2) Pertaining to or occurring in or as if in a tube of fine bore.
3) Physics: Pertaining to → capillarity.
4) Anatomy: One of the minute blood vessels between the terminations of the arteries and the beginnings of the veins (Dictionary.com).

From L. capillaris "pertaining to hair," from capillus "hair."

Muyin, muyiné, from mu(y), → hair.

The ability of a → liquid to → flow in a → narrow space, such as a thin → tube, without the assistance of, and in opposition to, external forces like → gravity. Also called → capillarity. It occurs because of intermolecular → attractive forces between the liquid and solid surrounding surfaces. If the diameter of the tube is sufficiently small, then the combination of → surface tension (which is caused by → cohesion within the liquid) and → adhesion (between the liquid and the → container) acts to lift the liquid. The capillarity of the liquid is high when adhesion is greater than cohesion. For example, water in a thin glass tube has strong → adhesive forces due to the hydrogen bonds that form between the water molecules and the oxygen atoms in the glass wall (made of → silica, SiO₂). In contrast, mercury is characterized by stronger cohesion, and hence its capillarity is much lower.

→ capillary; → action.

→ Tropic of Capricorn.

→ Capricornus.