# Dominant group/Astronomy

In theory, the relationship between the term dominant group and astronomy involves astronomical entities. This may be of two types: (1) a dominant group of astronomical entities, or (2) a dominant group in some way associated with astronomical entities.
Any astronomical dominant group, or its synonyms, is an astronomical entity.

## Dominant groups

Examples from primary sources are to be used to prove or disprove each hypothesis. These can be collected per subject or in general.
* Accident hypothesis: dominant group is an accident of whatever processes are operating.
* Artifact hypothesis: dominant group may be an artifact of human endeavor or may have preceded humanity.
* Association hypothesis: dominant group is associated in some way with the original research.
* Bad group hypothesis: dominant group is the group that engages in discrimination, abuse, punishment, and additional criminal activity against other groups. It often has an unfair advantage and uses it to express monopolistic practices.
* Control group hypothesis: there is a control group that can be used to study dominant group.
* Entity hypothesis: dominant group is an entity within each field where a primary author of original research uses the term.
* Evolution hypothesis: dominant group is a product of evolutionary processes, such groups are the evolutionary process, produce evolutionary processes, or are independent of evolutionary processes.
* Identifier hypothesis: dominant group is an identifier used by primary source authors of original research to identify an observation in the process of analysis.
* Importance hypothesis: dominant group signifies original research results that usually need to be explained by theory and interpretation of experiments.
* Indicator hypothesis: dominant group may be an indicator of something as yet not understood by the primary author of original research.
* Influence hypothesis: dominant group is included in a primary source article containing original research to indicate influence or an influential phenomenon.
* Interest hypothesis: dominant group is a theoretical entity used by scholarly authors of primary sources for phenomena of interest.
* Metadefinition hypothesis: all uses of dominant group by all primary source authors of original research are included in the metadefinition for dominant group.
* Null hypothesis: there is no significant or special meaning of dominant group in any sentence or figure caption in any refereed journal article.
* Object hypothesis: dominant group is an object within each field where a primary author of original research uses the term.
* Obvious hypothesis: the only meaning of dominant group is the one found in Mosby's Medical Dictionary.
* Original research hypothesis: dominant group is included in a primary source article by the author to indicate that the article contains original research.
* Primordial hypothesis: dominant group is a primordial concept inherent to humans such that every language or other form of communication no matter how old or whether extinct, on the verge of extinction, or not, has at least a synonym for dominant group.
* Purpose hypothesis: dominant group is written into articles by authors for a purpose.
* Regional hypothesis: dominant group, when it occurs, is only a manifestation of the limitations within a region. Variation of those limitations may result in the loss of a dominant group with the eventual appearance of a new one or none at all.
* Source hypothesis: dominant group is a source within each field where a primary author of original research uses the term.
* Term hypothesis: dominant group is a significant term that may require a 'rigorous definition' or application and verification of an empirical definition.

## Active regions

Notation: let the symbol AR stand for active region.
          let the symbol SDR stand for surface differential rotation.
          let the symbol ΔP stand for a change in rotational period.
"[A] star lacking one dominant AR, or with several ARs spaced in longitude, might not show a clear rotational signal."
SDR "will most easily be detected among stars that have relatively stable modulation over several rotations within a season from a dominant group of ARs that experience a noticeable change in mean AR latitude (corresponding to a change in mean rotational period) between consecutive observing seasons."
"On very active stars with large filling factors, ΔP may be minimized because the periods determined might only result from a limited latitude band where enough "gaps" in the plage exist to permit detection of rotation modulation." ΔP equals the maximum observed rotational period (P$_{max}$) minus the minimum (P$_{min}$).

## Astrobiology

"The phylum Chloroflexi is a dominant group at organic-rich sites lacking hydrates."
"Before the great oxidation event, a group of single-celled microorganisms, called methanogens were the dominant group of organisms in early earth."
"The right hemispheric dominant group is hyperdigoxinemic, left hemispheric dominant group is hypodigoxinemic and bihemispheric dominant group is normodigoxinemic."

## Galactic cosmic rays

Notation: let the symbol Z stand for atomic number.
          let the symbol PeV stand for 10$^{15}$ electron volts.
"The most dominant group is the iron group (Z = 25 − 27), at energies around 70 PeV more than 50% of the all-particle flux consists of these elements."

## Galaxy groups

Notation: let the symbol keV stand for 10$^3$ electron volts.
Compact groups of galaxies are tight associations of galaxies. Their compactness suggests extremely short crossing times and a very rapid evolution. Computer simulations suggest that a compact "group coalesces into a giant dominant galaxy in a small number of crossing times." "Alternately, compact groups may be transient unbound cores of loose groups". A third alternative is that they are mostly chance alignments within larger loose groups of galaxies.
"In a physically dense group one would expect that the majority of the galaxies would exhibit visible signs of interaction."
"At the same time, the dominant group members are as likely to be spirals as ellipticals, hence suggesting that systematic merging has not (yet) occurred".
"Regardless that their member galaxies are dominated by spiral galaxies, we detected extended thermal X-ray emission that is attributed to hot gas with a temperature of 1.04±0.10 keV."
"This is the second clear detection of thermal X-ray emission from a spiral-dominant group of galaxies after HCG 92."
"To that end we used the very compact 375-m array of the Australia Telescope Compact Array (ATCA; Frater et al. 1992)1 to search for intergalactic H I gas in the NGC 1808 group, conducting observations centred between NGC 1792 and NGC 1808, the two dominant group members."
"The hard emission of the starburst galaxies can be divided into two groups; point source dominant and diffuse source dominant."
"The X-ray luminosity of the dominant group [of galaxies] is an order of magnitude fainter than that of the X-ray jet."

## Interstellar medium

Interstellar dust can be studied by infrared spectrometry, in part because the dust is an astronomical infrared source and other infrared sources are behind the diffuse clouds of dust.
"In diffuse clouds the dominant group appears to be -CH$_3$."

## Mira variables

A Mira variable, or Mira-type variable, is a class of pulsating variable stars characterized by very red colors, pulsation periods longer than a hundred days, and light amplitudes greater than one magnitude.
"The rotational transitions within vibrationally excited states of $^{28}$SiO (SiO hereafter) show intense maser emission in objects such as AGB stars, mostly O-rich Mira-type variables, as well as in a few star-forming regions."
"The sample was made up of Mira-type variables, semiregular AGB stars, red supergiants and one star-forming region (Orion IRc2)." "Of a total of 21 objects in the sample, we have covered more than 8 full cycles for 13 regular variables, mostly Mira-type stars."
"The goal was to record between 10 and 15 spectra per pulsation cycle in Mira-type variables, the dominant group in the sample."

## Preflare spectrum

The microdensitometer tracings from a low-inductance vacuum spark are compared with spectra from the OSO 3 satellite.
"The preflare spectrum and the 14 kV spectrum both have Fe XVIII as the dominant group of lines"

## Formation of binary stars

"A proposed mechanism for the formation of binary and multiple systems is that of 'prompt initial fragmentation'" of the dense molecular cloud during the formation of protostars in bound groups. For a binary, the protostar fragments into two protostars which then collapse to form the binary system.
"In almost all close encounters the energy and angular momentum transfer is dominated by disc material becoming unbound from the system, with the contributions from close disc particle - star encounters being significant."
"The third is by far the dominant group, comprising 50 per cent of particles."

## Subdwarfs

"The dominant population" in the Palomar-Green Catalog of Ultraviolet Excess Stellar Objects "is that of the hot, hydrogen atmosphere subdwarfs, the sdB stars, which comprise nearly 40 percent of the sample." "The helium-rich sdO stars account for 13% of the total. The hot white dwarfs of spectral types DA, DB, and DO account for 21%, 2.8%, and 1.0% of the sample; cooler DC or DZ white dwarfs add another 1.2%"
The Palomar Green (PG) "survey is complete to B ≤ 16.2 for objects showing ultraviolet excesses U - B ≤ -0.4 for one-fourth of the sky at high galactic latitude". There may be numerous cataclysmic variables (CVs) "with spectra predominantly in absorption in the PG catalog of over 1800 blue objects."
"Many such objects might have been categorized as hot subdwarfs (sdB, sdO), the dominant group of PG objects, or as white dwarfs, because the initial spectral classifications were done at low resolution with spectra of highly variable quality."

## White dwarfs

"White dwarfs are end-products of stellar evolution. The fundamental properties of the dominant group of nonmagnetic white dwarfs have been invaluable in constraining the theory of single star evolution." Of the 2551 white dwarf stars from the full spectroscopic white dwarf and hot subdwarf sample within the Sloan Digital Sky Survey (SDSS) first data release, DR1, 1888 are non-magnetic DA types and 171, non-magnetic DBs. "White dwarfs are the most readily studied of the end products of stellar evolution. Investigations of white dwarfs have generally focused on the dominant group of the nonmagnetic variety for which realistic model atmospheres can be constructed and stellar parameters deduced." "White dwarfs are intensively studied end products of stellar evolution. However, investigations of white dwarfs have generally focused on the dominant group of nonmagnetic stars for which realistic model atmospheres can be constructed and fundamental properties, such as their masses or interior chemical composition can be determined."
Notation: accretion induced collapse (AIC).
          binary millisecond pulsars (BMSPs).
          white dwarf (WD).
"If we focus on BMSPs with WD companions, which is the dominant group in the observed sample, our results indicate birth rates that are ∼ 10 times higher for BMSPs that come from the AIC route."

## Genera differentia

The genera differentia for possible definitions or relative synonyms of "dominant group" fall into the following set of orderable pairs:
Genera differentia for "dominant group" :
| Synonym for "dominant" | Category Number | Category Title | Synonym for "group" | Category Number | Catgeory Title |
| “superior” | 36 | SUPERIORITY | "arrangement" | 60 | ARRANGEMENT |
| “influential” | 171 | INFLUENCE | "class" | 61 | CLASSIFICATION |
| “musical note” | 462 | HARMONICS | "assembly" | 74 | ASSEMBLAGE |
| “most important” | 670 | IMPORTANCE | "size" | 194 | SIZE |
| “governing” | 739 | GOVERNMENT | "painting", "grouping" | 572 | ART |
| "master" | 747 | MASTER | "association", "set" | 786 | ASSOCIATION |
| ----- | --- | ------- | "sect" | 1018 | RELIGIONS, CULTS, SECTS |
Unless otherwise stated, the small group study designation such as "Astronomy" is placed at the beginning of the search stream, e.g., "astronomy class sect superior rules", without the quotes on Google Scholar. Another search stream with "astronomy" at the end may find fewer or slightly more articles.
Number of articles on Google scholar. :
| Genera Differentia | Popularity in articles | Small group study area | Popularity | "Dominant group" overlap | Concept usage |
| class sect superior rules | 89,200 | Astronomy | 22,700 | 488 | 22,212 |
| class arrangement superior rules | 196,000 | Astronomy | 24,200 | 200 | 24,000 |
In the first article, cited following: "class", "most of the optimization problems can be grouped into classes ... of similar complexity", "first class projects", and "classification"; "arrangement", "arrangement of observations", "the algorithms [for arrangement] are sensitive to the scientific policy"; "superior", "genetic algorithms are clearly superior if there is not a good knowledge of the main constraints in the scheduling of the observations."; "rules", "[t]he natural rules ... are selection of the best individuals [those better adapted to the scientific policy] of a population".
Def. superior [algorithms] based on rules [of selection] for the arrangement of classes [of observations] are called a dominant group [of algorithms].
'Orderable' means that any synonym from within the first category can be ordered with any synonym from the second category to form an alternate term for "dominant group"; for example, "superior class", "influential sect", "master assembly", "most important group", and "dominant painting". "Dominant" falls into category 171. "Group" is in category 61. Further, any word which has its most or much more common usage within these categories may also form an alternate term, such as "ruling group", where "ruling" has its most common usage in category 739, or "dominant party", where "party" is in category 74. "Taxon" or "taxa" are like "species" in category 61. "Society" is in category 786 so there is a "dominant society".
"A related, but separate, definition relies on a linguistic identity that differs from that of the dominant society [5]."
From theoretical astronomy, a "dominant group" is an astronomical entity which has many genera differentia words that may form orderable pairs that are alternate, relative, synonymous terms. Here are some examples:

### Dominant species

* "At the low density given by the spherically symmetric wind model (see Table 1), the dominant species in the gas are atomic ions while as the gas number density increases, the recombination of ions takes place and the gas composition is governed by neutral-phase chemistry, that is, the dominant species are neutral atoms and molecules although electrons and some ions are still present in relatively large amounts (for example, C$^+$, O$^+$ and He$^+$)."
* "From the geometry and scaling laws the contribution of a clump of radius R to the number of particles N of each species is ... where η$_C$ is the carbon abundance and we are implicitly assuming that all the carbon is in the form of the dominant species in each zone."

### Greatest group

"First of all there were only fifteen groups seen during the entire year [1901], north and south put together. Of these, seven were in the north, and the mean latitude for the north was 8.6°, exactly the latitude of one spot of the seven, and this very naturally, seeing that it was by far the greatest group of the year, the celebrated "eclipse group."" Bold added. Eclipse group is also a relative synonym for dominant group.

### Influential group

* "Finally, and perhaps most importantly, London was the institutional home of the most influential group of astronomers of the period: the Royal Astronomical Society."
* "During the first five years (the 'formative era') the Branch flourished under the guidance of what was collectively the most influential group of amateur astronomers in the country."

## Hypotheses

* Dominant group in astronomy is limited to entities that dominant by some physical quantity such as size, characteristic, or numerousness.