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

A curve, on the pressure versus specific volume plane, representing the locus of all the possible states that can be reached by a substance immediately after the passage of a single → shock wave. For each initial condition there is a different curve. No combustion occurs in the process and, therefore, the chemical composition of the medium does not change. See also → Rayleigh line; → Crussard curve.

Named after the French physicist Pierre Henri Hugoniot (1851-1887), who worked on fluid mechanics, especially flow properties before and after shock waves; → curve.

A → pulsar with a period of 59 milliseconds (17 pulses per second) moving around a compact companion in an elongated orbit (period 7.75 hours). It is thought that the companion is probably also a → neutron star with the same mass as the pulsar (1.4 solar masses). The orbit is gradually shrinking because of → gravitational radiation, as predicted by the theory of → general relativity. See also → binary pulsar, → millisecond pulsar.

Named after the American physicists Russell Hulse and Joseph Taylor of Princeton University, who discovered the pulsar in 1974, for which they shared the 1993 Nobel prize in physics; → pulsar.

1) (adj.) Belonging or pertaining to or of the nature of man or mankind, contrasted with animals.
2) (n.) A human being, → man. See also → anthropo-.

M.E. from M.F. humain, from L. humanus "of man, human," also "humane, kind, gentle, polite," probably related to homo "man," and to humus "earth," on notion of "earthly beings."

Martu, → man, + -gân a suffix forming nouns or adjectives denoting relation and plurality.

1) Any system or mode of thought or action in which human interests, values, and dignity predominate (dictionary.com).
2) Philo.: A variety of ethical theory and practice that emphasizes reason, scientific inquiry, and human fulfillment in the natural world and often rejects the importance of belief in God (dictionary.com).

→ human + → -ism.

A person having a strong interest in or concern for human welfare, values, and dignity (dictionary.com).

→ human + → -ist.

Having concern for or helping to improve the welfare and happiness of people (dictionary.com).

→ humanity + -arian a suffix forming nouns and adjectives, from -ari(us) or -ary + -an.

Martugândust, literally "friend/lover of humanity," from martugân, → humanity, + dust "friend," Mid.Pers. dôst "friend," dôšidan "to love, like, choose;" O.Pers. dauštā- "friend;" Av. zuš- "to take pleasure;" PIE root *geus- "to taste, like, choose;" cf. Skt. jos- "to like, enjoy;" Gk. geuomai, L. gustus "taste, enjoyment" (Cheung 2007).

The study of classical languages and classical literature.

Plural of → humanity.

Martugânik, from martugân, → human, + → -ik, → -ics.

1) All human beings collectively; the human race; humankind.
2) The quality of being human; human nature.

→ human + → -ity.

1) To render humane, kind, or gentle.
2) To make human.

→ human; → -ize.

A cold ocean current that flows northward along the western side of South America, offshore Chile and Peru. Dominate weather in this area includes coastal fog and low clouds. The presence or lack of this current is a vital part of the weather pattern known as El Niño.

Named after the German naturalist and explorer Alexander von Humboldt (1769-1859). → current.

Containing or characterized by a high amount of water or water vapor; moist. → humidity.

Adj. of → humidity.

Namnâk, namur, from nam, → humidity + adj. suffixes -nâk and -ur, variant -var (Mid.Pers. -uwar, -war, from O.Pers. -bara, from bar- "to bear, carry"), as in ranjur, ganjur, dastur.

Generally, a measure of the water vapor content of the air. Popularly, it is used synonymously with → relative humidity. → absolute humidity, → dew point, → mixing ratio, → specific humidity.

Humidity, from O.Fr. humide, from L. humidus "moist, wet," variant (by influence of humus "earth") of umidus, from umere "be moist."

Nam "humidity, moisture," from Mid.Pers. nam, namb "moisture;" Av. napta- "moist," nabās-câ- "cloud," nabah- "sky;" cf. Skt. nábhas- "moisture, cloud, mist;" Gk. nephos "cloud, mass of clouds," nephele "cloud;" L. nebula "mist," nimbus "rainstorm, rain cloud;" O.H.G. nebul; Ger. Nebel "fog;" O.E. nifol "dark;" from PIE *nebh- "cloud, vapor, fog, moist, sky."

A series of → spectral lines in the → infrared spectrum of → neutral hydrogen emitted by electrons in → excited states transitioning to the level described by the → principal quantum number  n = 6. It begins at 12368 nm (Hu α 12.37 microns) and has been traced to 3281.4 nm (3.28 microns).

Named after Curtis J. Humphreys (1898-1986), American physicist; → series.

An empirical upper → luminosity boundary in the → H-R diagram. It consists of two sections, a sloping part and a horizontal part. The sloping part, which decreases with decreasing → effective temperature, corresponds roughly to the → Eddington limit. The horizontal part is the temperature-independent upper luminosity limit for late-type → hypergiants. It is thought that → massive stars above the Humphreys-Davidson limit encounter an → instability, possibly due to the opacity-modified Eddington limit, and experience high → mass loss episodes which prevent their evolution to cooler temperatures. → Luminous Blue Variable stars are examples of this high mass loss phase.

Named after Roberta M. Humphreys and Kris Davidson, who first dealt with this limit (1979, ApJ 232, 409); → limit.

An empirical rule stating that all orbitals of a given sublevel must be occupied by single electrons before pairing begins.

After the German physicist Friedrich Hund (1896-1997), known for his work on atoms and molecules. → rule.

The smallest three digit number in the decimal system and the smallest square of a two-digit number (10).

Hundred, from O.E. hundred "a counting of 100," from P.Gmc. *hunda- "hundred," as below, + *rath "reckoning, number."

Sad "hundred," from Mid.Pers. sad, sat, Av. sata- "hundred," satô.raocana- "with a hundred windows," satô.təmô.sata- "hundreds of hundred;" cf. Skt. śatá- "hundred;" Gk. hekaton; L. centum; Lith. simtas; P.Gmc. *hunda- "hundred" (Goth. hund; O.H.G. hunt); PIE *kmtom "hundred."

To chase or search for (game or other wild animals) for the purpose of catching or killing (Dictionary.com). See also → poach, → poaching.

M.E, hunten, from O.E. huntian "chase game," from hunta "hunter," and related to hentan "to pursue."

Šekâridan, šekâr kardan, from šekâr "hunt;" variant bešgar(d) "hunter, fowler; chase; game; place for hunting;" Parthian Mid.Pers. škr "to hunt, pursuit;" Sogdian škr-, (')škr- "to lead, take; pursue, persecute," prefixed 'pškr- "to chase;" Proto-Ir. *skar- "to pursue, drive, look for (the cattle);" + -gar, → -or.

A person who hunts game or other wild animals for food or in sport (Dictionary.com).

→ hunt; → -er.

A diagram where the surface → nitrogen  → chemical abundance of stars is plotted against their → projected rotational velocity (v sini).

I. Hunter et al., 2009, A&A, 496, 841; → diagram.

An intense warm-core oceanic cyclone that originates in tropical latitudes; called a typhoon in the western Pacific Ocean. Sustained winds are 120 km per hr or higher.

Hurricane, from Sp. huracán, from Taino (the language of an extinct Arawakan Indian tribe of the West Indies) hurakán.

Tufand, from tufidan "to roar, to raise a tumult," tufân "storm, the roaring of the sea, the confused hum of men or animals." Is this Persian word related to Gk. typhon "whirlwind," personified as a giant, father of the winds?