An Etymological Dictionary of Astronomy and Astrophysics
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فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 60 Search : nebula
Orion Nebula
  میغِ شکارگر، ~ ِ ا ُریون   
miq-e Šekârgar, ~ Oryon

Fr.: Nébuleuse d'Orion   

The best known → ionized nebula and one of the nearest regions to the Sun in which stars are presently being formed. It is visible to the naked eye in the constellation → Orion south of → Orion's Belt as a fuzzy patch. It lies about 1,500 → light-years away and measures about 30 light-years across. The Orion Nebula is ionized and made visible by a small group of → O-type and → B-type stars known as the → Trapezium cluster. Other designations: M 42, NGC 1976. See also: → Orion molecular cloud; → Huygens Region ; → Orion association; → Orion Bar; → Orion Bright Bar.

Orion; → nebula.

Owl Nebula
  میغِ بوف، ~ِ جغد   
miq-e buf, ~ joqd

Fr.: Nébuleuse de la Chouette   

A planetary nebula in the constellation → Ursa Major, one of the four planetary nebulae in → Messier catalog. It is one of the more complex planetary nebulae known. Its appearance has been interpreted as that of a cylindrical torus shell viewed obliquely, so that the projected matter-poor ends of the cylinder correspond with the Owl's eyes. Also known as M97 or NGC 3587.

Discovered by Pierre Méchain in 1781, the name goes back to Lord Rosse, who first used it in 1848. Owl, from O.E. ule, from P.Gmc. *uwwalon (cf. Du. uil, O.H.G. uwila, Ger. Eule), a diminutive of root *uwwa, which is imitative of an owl's hoot (cf. L. ulula "owl;" Gk. ololyzein "to cry aloud," Skt. uluka- "owl.;" → nebula.

Miq, → nebula; buf "owl;" Mid.Pers. bûf "owl," Av. buxti- "hiss, howling;" cf. Skt. bukk- "to bark, yelp;" Gk. buas "owl;" L. bubo "owl" (Fr. hibou); Arm. bou "owl." Joqd "owl," probably related to jiq "shreak, clamour, cry."

Pelican Nebula
  میغ ِ پلیکان   
miq-e pelikân

Fr.: Nébuleuse du Pélican   

An → H II region, also known as IC 5067 and IC 5070, about 2,000 → light-years away in the constellation → Cygnus. It is part of a much larger, complex star-forming region also containing the larger and bright → North America Nebula.

So named because of its resemblance to a pelican on long exposure images. M.E. pellican; O.E. pellicane, from L.L. pelecanus, from Gk. pelekan "pelican:" → nebula.

Pencil Nebula (NGC 2736)
  میغ ِ کلک   
miq-e kelk

Fr.: Nébuleuse du Crayon   

A small part of the → Vela supernova remnant with a narrow appearance. The Pencil Nebula measures about 0.75 → light-years across, is about 5 light-years long, and lies about 800 light-years from Earth. It is moving through the → interstellar medium at about 650 000 kilometres per hour.

pencil; → nebula.

Pipe Nebula
  میغ ِ پیپ   
miq-e pip

Fr.: Nébuleuse de la Pipe   

An extended complex of → molecular clouds in the constellation → Ophiuchus, apparently shaped like a smoker's pipe, about 5° in size and located about 5° away from the → Galactic center. It has a mass of 104 solar masses, lies at a distance of about 130 pc, and is among the closest molecular clouds to Earth. The Pipe Nebula includes a number of → dark nebulae, including Barnard 59, 65, 66, 67, 77, 244, and 256. It is of particular interest because of the almost complete lack of → star formation within it. This cloud is an extremely rare example of a relatively massive molecular cloud that may be in a state of evolution prior to the onset of significant star-forming activity.

pipe; → nebula.

planetary nebula
  میغ ِ سیاره‌ای   
miq-e sayyâreyi

Fr.: nébuleuse planétaire   

A hot envelope of gas ejected from a central evolved star before becoming a → white dwarf. At the end of the → asymptotic giant phase the pulsating → red giant star is surrounded by an extended shell formed by the material ejected from it. As the evolved star contracts, its → effective temperature rises considerably. When it reaches about 30,000 K, the radiated photons become energetic enough to ionize the atoms in the nebula. The nebula becomes then visible in the optical. It shines essentially in a few → emission lines, produced by cascades during recombination or by collisional excitation with electrons. The central stars of planetary nebulae, → CSPNe, are typically 0.6 to 0.8 solar masses. They have → main sequence masses in the range 1 to 8 solar masses, with an average mass of 2.2 solar masses for a standard → initial mass function. Thus a total of about 1.6 solar masses is in average lost during the → AGB and planetary nebula phases. The life-time of planetary nebulae is relatively short. A typical planetary nebula lasts only a few 10,000 years.

planetary; → nebula. The name comes from the fact that these objects appear as planetary disks in a low-resolution telescope. The first planetary nebula, designated NGC 7009 or the → Saturn Nebula, was discovered in 1782 by the German-born English astronomer William Herschel (1738-1822), who described it as "planetary nebula."

post-planetary nebula star
  ستاره‌ی ِ پسا-میغ ِ سیاره‌ای   
setâre-ye pasâ-miq-e sayyâre-yi

Fr.: étoile post-nébuleuse planétaire   

An evolved star whose → planetary nebula has dissipated.

post-; → planetary; → nebula; → star.

preplanetary nebula (PPN)
  پیش-میغ ِ سیاره‌ای   
piš-miq-e sayyâre-yi

Fr.: pré-nebuleuse planétaire   

A short-lived transition object between the → asymptotic giant branch (AGB) and → planetary nebula phases. See also → post-asymptotic giant branch star (post-AGB).

pre-; → planetary; → nebula. The more commonly used term, → protoplanetary nebula, is a misnomer and must be avoided. Indeed → protoplanetary is widely used to refer to disks around → pre-main sequence stars. Since the term → protoplanet is used to denote planets undergoing formation, the use of the term "protoplanetary nebula" to mean a completely different kind of object is an unfortunate choice (Sahai et al. 2005, ApJ 620, 948).

protoplanetary nebula
  پیش-میغ ِ سیاره‌ای   
piš-miq-e sayyâre-yi

Fr.: pré-nebuleuse planétaire   

preplanetary nebula.

proto-; → planetary; → nebula.

pulsar wind nebula (PWN)
  میغ ِ باد ِ پولسار، ~ ~ تپار   
miq-e bâd-e pulsâr, ~ ~ tapâr

Fr.: nébuleuse de vent de pulsar   

Same as → plerion.

pulsar; → wind; → nebula.

reflection nebula
  میغ ِ بازتابی   
miq-e bâztâbi

Fr.: nébuleuse par réflexion   

A type of nebula that is visible from its reflection of starlight. Bright stars near reflection nebulae emit light into the region that is reflected by the large amount of dust there. The size of the dust grains causes blue light to be reflected more efficiently than red light, so these reflection nebulae frequently appear blue in color.

reflection; → nebula.

Ring Nebula
  میغ ِ حلقه   
miq-e halqé

Fr.: Nébuleuse de l'Anneau   

A bright → planetary nebula in the constellation → Lyra, also called M57 or NGC 6720. In small telescopes it has the appearance of a slightly elliptical luminous ring around a central hot star (15th magnitude). The radius is one-third of a → light-year, and the nebula is about 2,000 light-years away.

ring; → nebula.

Rosette Nebula
  میغ ِ گلسان   
miq-e golsân

Fr.: nébuleuse de la Rosette   

A giant H II region of about 1° in diameter, lying about 5000 light-years away in the Milky Way, the constellation → Monoceros. It is ionized by the cluster NGC 2244, a group of hot young stars at the center of the nebula. Also called M16, the brighter portions of the nebula have been assigned different NGC numbers: 2237, 2238, 2239, and 2246.

Rosette "a rose-shaped ornament," from Fr. rosette, from O.Fr. rosette, diminutive of rose "rose;" L. rosa, probably from Gk. wrodon (Aeolic), then rhodon, a loan from Iranian, as below; → nebula.

Miq, → nebula; golsân "resembling rose, flower," from gol "flower, rose," variants vard (sohre-vard "red rose"), Semnâni dialect vela "rose;" Mid.Pers. *vard, gul, loaned in Arm. vard and Ar. ward; Av. varəδa- "rose;" loaned in Gk. wrodon (Aeolic), then rhodon; + -sân "manner, semblance" (variant sun, Mid.Pers. sân "manner, kind," Sogdian šôné "career").

Saturn Nebula
  میغ ِ کیوان   
miq-e Keyvân

Fr.: nébuleuse Saturne   

A planetary nebula in the Aquarius constellation discovered by William Herschel in 1782. It has a size of about 0.3 x 0.2 light-years and lies about 1400 light-years away. Also known as NGC 7009.

Saturn, such named by Lord Rosse in the 1840s, because the object has a vague resemblance to the planet Saturn in low-resolution telescopes; → nebula.

solar nebula
  میغ ِ خورشیدی   
miq-e xoršidi

Fr.: nébuleuse solaire   

The cloud of interstellar gas and dust from which the Sun and the rest of the solar system initially formed.

solar; → nebula.

spiral nebula
  میغ ِ مارپیچ   
miq-e mârpic

Fr.: nébuleuse spirale   

An obsolete term used to describe nebular objects with spiral shape before it was understood that they are independent galaxies lying outside our → Milky Way galaxy. Now called → spiral galaxy.

spiral; → nebula.

Swan Nebula
  میغ ِ قو   
miq-e qu

Fr.: nébuleuse du Cygne   

Same as → Omega Nebula.

swan; → nebula.

Tarantula Nebula
  میغ ِ رتیل، ~ ِ رطیل   
Miq-e Roteyl

Fr.: Nébuleuse de la Tarantule   

The largest and brightest → H II region in the → Large Magellanic Cloud. This → giant H II region has a diameter of over 800 → light-years, and contains half a million → solar masses of ionized gas. The ionization is produced by several clusters of → O-type and → B-type stars, including the very powerful and compact cluster → R136 near its centre. The nebula's name comes from its spider-like shape. Also known as → 30 Doradus and NGC 2070.

Tarantula "any of several large, hairy spiders of the family Theraphosidae," from M.L. tarantula, from It. tarantola, from Taranto "seaport city in southern Italy in the region where the spiders are frequently found," from L. Tarentum, from Gk. Taras; → nebula.

Miq, → nebula; roteyl "large, hairy spider, tarantula."

Trifid Nebula
  میغ ِ سه‌پاره   
miq-e sepâré

Fr.: nébuleuse Trifide   

A large luminous → H II region in the constellation → Sagittarius. Also known as M20, NGC 6514. Conspicuous → dust lanes radiating from the center appear to divide the nebula in three → lobes. It is a combined → emission nebula and → reflection nebula, extending for nearly 30' on the sky. Its estimated distance is 4100±200 → light-years (Kuhn et al., 2018, arXiv:1807.02115).

Trifid, from L. trifidus "split in three," from → tri- + fidus "divided," from findere "to split;" → nebula.

Miq, → nebula; sepâré "split in three," from , → three, + pâré "piece, part, portion, fragment;" Mid.Pers. pârag "piece, part, portion; gift, offering, bribe;" Av. pāra- "debt," from par- "to remunerate, equalize; to condemn;" PIE *per- "to sell, hand over, distribute; to assigne;" cf. L. pars "part, piece, side, share," portio "share, portion;" Gk. peprotai "it has been granted;" Skt. purti- "reward;" Hitt. pars-, parsiya- "to break, crumble."

Veil Nebula
  میغ ِ واشامه   
miq-e vâšâmé

Fr.: Nébuleuse du Voile   

A part of the → Cygnus loop, an old → supernova remnant.

veil; → nebula.

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