An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



<< < -ul ult unb und uni uni unr upp Urs > >>

Number of Results: 179
   -اول، -اوله   
-ul, -ulé

Fr.: -ule   

A suffix meaning "small, little," as in → formula, → globule, → module, capsule, nodule.

From Fr. -ule, from L. diminutive suffix -ulus (feminine -ula, neuter -ulum).

Pers. diminutive suffix -ul, ulé, as in:
zangulé, zangul "small bell;"
kutulé, kutul "dwarf;"
golulé, gullé "small ball; bullet;"
maškulé (Torbat Heydariye-yi) "small water-skin;"
kandulé "a small jar for holding grain;"
jâšulé = small donkey (Kurd.);
Ahmadulé = little Ahmad (Kurd.);
rulé = "little child" (Kurd., Tâleši, Borujerdi, Malâyeri, and other Western dialects of Iran) probably from *ruduleh, cf. rud "child" (in zâd-o-rud) and Gilaki rey "boy;"
digul (Šuštari), digulé (Qomi) "small casserole, little pot;"
This suffix occurs also as -ulu, -âlé, and -élé as, e.g., in kuculu, cangul, panjul, bozqâlé, dâsqâlé, kâselé (Farâhâni) "small bowl," and barfelé (Farâhâni) "little snow."
Examples of use in this dictionary: disul → formula; karpul → corpuscle. See also -al → -al

U Antliae
   U تلمبه   
U Tolombé

Fr.: U Antliae   

A → carbon star of the → asymptotic giant branch type located in the constellation of → Antlia. Its other designations are HIP 51821 (→ Hipparcos Star Catalogue), HD 91793, and HR 4153. U Antliae is an → irregular variable that changes its → visual magnitude between 5.27 and 6.04. About 850 → light-years from Earth, it shines with a → luminosity approximately 8,000 times that of the → solar luminosity and has a → surface temperature 2,800 K. It is surrounded by a complex structure of dust shells. Around 2,700 years ago, U Antliae went through a short period of rapid → mass loss. During this period of only a few hundred years, the material making up the shell seen in the → Atacama Large Millimeter Array (ALMA) data was ejected at high speed (Kerschbaum et al., 2017, A&A 605, A116, arXiv:1708.02915).

U, according to → variable star designation; → Antlia.

U Geminorum
   U دوپیکر   
U Dopeykar

Fr.: U Gémeaux   

The prototypical and first discovered → cataclysmic variable. It is a → dwarf nova system with a relatively long → orbital period of 4 hr 17 minutes. U Gem undergoes → outbursts on time-scales between 30 and 250 days and shows → grazing occultations. The → accretion disk is partially eclipsed, but the → white dwarf remains visible during mideclipse. The mass of the white dwarf → primary is estimated to be 1.24 Msun, about two times higher than the mass of the → secondary; the → angle of inclination is 69°.7 (P. J. Groot 2001, ApJ 551, L89).

variable star designation; → Gemini.

  ویسپ‌باشنده، ویسپ‌باش، ویسپ‌باشا   
visp-bâšandé, visp-bâš, visp-bâšâ

Fr.: omniprésent   

Existing or being everywhere, especially at the same time; omnipresent.

From L. ubiquitarius, from ubique "everywhere," from ubi "where" + que "any, also, ever."

From visp-, → omni-, + bâšandé, bâš, bâšâ "existing, being," from budan "to be," → condition.

  ویسپ‌باشندگی، ویسپ‌باشی، ویسپ‌باشایی   
visp-bâšandegi, visp-bâši, visp-bâšâyi

Fr.: ubiquité, omniprésence   

The state or capacity of being everywhere, especially at the same time; omnipresence.

From M.Fr. ubiquité, from L. ubique "everywhere," → ubiquitous; → -ity.

Noun from visp-bâšandé, visp-bâš, visp-bâšâyi, → ubiquitous.

UBV system
  راژمان ِ UBV   
râžmân-e UBV

Fr.: système photométrique UBV   

A → photometric system which consists of measuring an object's → apparent magnitude through three broad-band filters: the ultraviolet (U) at 3650 Å, the blue (B) at 4400 Å, and the visual (V) in the green-yellow spectral region at 5500 Å. The filter bandwidths are 680, 980, and 890 Å respectively. The system is defined so that for A0 stars B - V = U - B = 0. The system was devised by Harold Johnson (1921-1980) and William Morgan (1906-1994) at Yerkes Observatory. It was extended to the R and I bands centered at 7000 and 9000 Å respectively and later to other infrared bands.

U, B, and V referring to "ultraviolet," "blue," and "visible" respectively; → system.


Fr.: OVNI   

Short for → unidentified flying object.

unidentified flying object.

UFO sighting
  دیدار ِ یوفو   
didâr-e UFO

Fr.: vision d'OVNI   

The act or occasion of catching sight of a UFO.

UFO; sighting, from sight, M.E. from O.E. sihth; cf. Dan. sigte, Swed. sigt, Du. zicht, O.H.G. siht, Ger. Sicht, Gesicht, related to see.

Didâr "sight, vision," verbal noun from didan "to see" (Mid.Pers. ditan "to see, regard, catch sight of, contemplate, experience;" O.Pers. dī- "to see;" Av. dā(y)- "to see," didāti "sees;" cf. Skt. dhī- "to perceive, think, ponder; thought, reflection, meditation," dādhye; Gk. dedorka "have seen").


Fr.: ufologie, ovnilogie   

A term that describes the collective efforts of those who study → unidentified flying object (UFO) reports.

Ufo, from → unidentified flying object; → -logy.

UHECR puzzle
  چیستان ِ پرتوهای ِ کیهانی ِ اولتر-مه-کاروژ   
cistân-e partowhâ-ye keyhâni-ye ultar-meh-kâruž

Fr.: énigme des rayons cosmiques de très haute énergie   

The question of the origin and nature of the → ultra high energy cosmic rays. According to the → GZK cutoff, the UHECRs should be nearby. They are expected to be exceptional, therefore visible by some astrophysical counterpart. However, there is nothing visible (within a few tens of → Mpc) in the direction of all the UHECR detected up to now.

UHECR; → puzzle.

  اولتوم، فرجامین   
ultom, farjâmin

Fr.: ultime   

Last; furthest or farthest; conclusive in a process or series; the highest or most significant.

L.L. ultimatus, p.p. of ultimare "to be final, come to an end," from L. ultimus "last, final, farthest, extreme," superlative of *ulter "beyond."

Ultom, from ul "up, upward," ulêh "upward, above," → ultra-, + -tom supelative suffix, → extreme.
Farjâmin "belonging to the end; concluding," from farjâm "end; conclusion," from Mid.Pers. farzâm "end; conclusion," farzâftan "to finish, to be perfect;" from Proto-Iranian *fra-gam- "to send; to finish" (cf. O.Pers. prāgama- "to go forth"), from *gam- "to go; to come;" cf. Av. gam- "to come; to go," jamaiti "goes;" O.Pers. gam- "to come; to go;" Mod./Mid.Pers. gâm "step, pace," âmadan "to come;" cf. Skt. gamati "goes;" Gk. bainein "to go, walk, step;" L. venire "to come;" Tocharian A käm- "to come;" O.H.G. queman "to come;" E. come; PIE root *gwem- "to go, come."

ultimate fate of the Universe
  سرنوشت ِ فرجامین ِ گیتی   
sarnevešt-e farjâmin-e giti

Fr.: sort utlime de l'Univers   

The future evolution of the → Universe which is a subject of study in → cosmology. The ultimate fate of the Universe can be explored using → general relativity. And since there is more than one possible solution to the equations of general relativity, there is more than one possible ultimate fate of the Universe. Moreover, the fate will depend on three factors: the Universe's overall shape or → geometry, its → dark energy content, and the → equation of state parameter. See also: → oscillating Universe, → Big Rip, → Big Crunch, → Big Freeze, → heat death.

ultimate; → Universe.

ultar- (#)

Fr.: ultra-   

A prefix occurring originally in loanwords from L., with the basic meaning "on the far side of, beyond, extremely."

From L. ultra- from ultra (adverb and preposition) "beyond, on the further side," from *ulter, from uls "beyond;" + *-ter suffix of comparative adj.; PIE base *al- "besides, other, beyond."

Ultar-, from Mid.Pers. ul "up, upward," ulêh "upward, above" (Av. ərəδuua- "upright, risen; cf. Skt. ūrdhvá- "high, above, elevated; Gr. orthos "set upright, straight;" L. arduus "high, steep;" → ortho-) + -tar suffix forming comparative adjectives (Mid.Pers. -tar; Av. -tara- (masculine); PIE base *-tero).

ultra-diffuse galaxy (UDG)
  کهکشان ِ اولتر-پخشیده   
kahkešân-e ultar-paxšide

Fr.: galaxie ultra-diffuse   

A galaxy of low stellar density, defined to have low central → surface brightness (> 24 mag arcsec-2) and an → effective radius (Re) of over 1.5 kpc. The question of whether UDGs represent a separate class of galaxies is still under debate. Currently, known UDGs that have been discovered in clusters, in groups, and in the field can have Re as large as 5 kpc which is comparable to that of giant Milky Way like galaxies. This fact has been used to suggest that UDGs are "failed" giants. As Re captures (at most) the central parts of giant galaxies, whether this radius can be used to fairly compare the sizes of UDGs to the more massive galaxies is questionable (see, e.g., Chamba et al., 2020, A&A 633, L3).

Term proposed by van Dokkum et al. (2015), arXiv: 1410.8141v2; → ultra-; → diffuse; → galaxy.

ultra-high-energy cosmic ray (UHECR)
  پرتوهای ِ کیهانی ِ اولتر-مه-کاروژ   
partowhâ-ye keyhâni-ye ultar-meh-kâruž

Fr.: rayons cosmiques de très haute énergie   

A particle belonging to the most energetic population of → cosmic rays with an energy above ~ 1020 → electron-volts. The UHECRs constitute a real challenge for theoretical models, because their acceleration requires extreme conditions hardly fulfilled by known astrophysical objects. See also → UHECR puzzle, → Greisen-Zatsepin-Kuzmin cutoff.

ultra- + → high-energy cosmic ray.

ultra-high-energy neutrino
  نوترینو‌ی ِ اولتر-مه‌کاروژ   
notrino-ye ultar-meh-kâruž

Fr.: neutrino ultra haute énergie   

A neutrino particle accelerated to energies above 1018 → electron-volts. They are produced by the interaction of → ultra-high-energy cosmic ray (UHECR)s with the → cosmic microwave background radiation. Also called → cosmogenic neutrinos. See also → Greisen-Zatsepin-Kuzmin limit.

ultra-; → high; → energy; → neutrino.


Fr.: ultracompact   

Extremely compact with respect to a comparison value. → ultracompact H II region, → ultracompact dwarf galaxy.

ultra-; → compact.

ultracompact dwarf galaxy (UCD)
  کهکشان ِ کوتوله‌ی ِ اولتر-همپک   
kahkešân-e kutule-ye ultar-hampak

Fr.: galaxie naine ultracompacte   

A type of very bright compact → stellar system (-14 ≤ MV≥ -12) that is intermediate between → globular clusters (GCs) and → compact elliptical galaxies (cEs). With masses of M > 2 × 106 Msun and radii > 10 → parsecs (pc), UCDs are among the densest stellar systems in the Universe. Nevertheless, the nature and origin of these objects is still widely debated. Early interpretations suggested that UCDs could be the most massive GCs or possibly the → tidally stripped remnants of → dwarf galaxies. However, there is evidence that both formation mechanisms could contribute to the UCD population. → Supermassive black holes (SMBHs) have been confirmed in most UCDs with masses M > 107 Msun. The most massive UCD discovered to date, M59-UCD3 (M* ~ 2 × 108 Msun, radius ~ 25 pc), hosts a SMBH (Ahn et al., 2018, arxiv/1804.02399, and references therein).

ultracompact; → dwarf; → galaxy.

ultracompact H II region
  ناحیه‌ی ِ H IIی ِ اولتر-همپک   
nâhiye-ye H II-ye ultar hampak

Fr.: région H II ultracompacte   

A very young → H II region fully embedded in its natal molecular cloud. Ultracompact H II regions are distinguished from classical H II regions by their small sizes (diameter ≥ 0.1 pc), high densities (Ne ≥ 105 cm-3), and high emission measures (EM ≥ 107 pc cm-6). Their typical ionized gas content is about 10-2  → solar masses, in contrast to classical H II regions with a mass of about 105 solar masses. Due to very important extinction, ultracompact H II regions are not accessible to visible wavelengths.

ultra-; → compact; → H II region.

ultracool dwarf
  کوتوله‌ی ِ اولترسرد   
kutule-ye ultarsard

Fr.: naine ultrafroide   

A star-like objects with an → effective temperature of less than 2,700 K. Ultracool dwarfs constitute a heterogeneous group including stars of extremely low mass as well as → brown dwarfs, and represent about 15% of the population of astronomical objects near the Sun.

ultra-; → cool; → dwarf.

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