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68-454: Capricornus is one of the 88 modern constellations , and was also one of the 48 constellations listed by the 2nd century astronomer Claudius Ptolemy . Its old astronomical symbol is [REDACTED] (♑︎). Under its modern boundaries it is bordered by Aquila , Sagittarius , Microscopium , Piscis Austrinus , and Aquarius . The constellation is located in an area of sky called the Sea or

136-402: A branch of astronomy , star formation includes the study of the interstellar medium (ISM) and giant molecular clouds (GMC) as precursors to the star formation process, and the study of protostars and young stellar objects as its immediate products. It is closely related to planet formation , another branch of astronomy . Star formation theory, as well as accounting for the formation of

204-478: A massive star-forming galaxy about 12.5 billion light-years away that is obscured by clouds of dust . At a mass of about 10 solar masses , it showed a star formation rate about 100 times as high as in the Milky Way . Stars of different masses are thought to form by slightly different mechanisms. The theory of low-mass star formation, which is well-supported by observation, suggests that low-mass stars form by

272-498: A result of a gravitationally instability leading to clumpy and in-continuous accretion rates. Recent evidence of accretion bursts in high-mass protostars has indeed been confirmed observationally. Several other theories of massive star formation remain to be tested observationally. Of these, perhaps the most prominent is the theory of competitive accretion, which suggests that massive protostars are "seeded" by low-mass protostars which compete with other protostars to draw in matter from

340-505: A single star, must also account for the statistics of binary stars and the initial mass function . Most stars do not form in isolation but as part of a group of stars referred as star clusters or stellar associations . The first stars were believed to be formed approximately 12-13 billion years ago following the Big Bang . Over intervals of time, stars have fused helium to form a series of chemical elements . Spiral galaxies like

408-493: A triangle whose vertices are α Capricorni (Giedi), δ Capricorni (Deneb Algiedi), and ω Capricorni . Ptolemy's method of connecting the stars of Capricornus has been influential. Capricornus is usually drawn as a goat with the tail of a fish. H. A. Rey has suggested an alternative visualization, which graphically shows a goat . The goat's head is formed by the triangle of stars ι Cap , θ Cap , and ζ Cap . The goat's horn sticks out with stars γ Cap and δ Cap. Star δ Cap, at

476-421: Is HCG 87 , a group of at least three galaxies located 400 million light-years from Earth ( redshift 0.0296). It contains a large elliptical galaxy , a face-on spiral galaxy , and an edge-on spiral galaxy. The face-on spiral galaxy is experiencing abnormally high rates of star formation , indicating that it is interacting with one or both members of the group. Furthermore, the large elliptical galaxy and

544-558: Is (gravitational contraction) Kelvin–Helmholtz mechanism , as opposed to hydrogen burning in main sequence stars. The PMS star follows a Hayashi track on the Hertzsprung–Russell (H–R) diagram . The contraction will proceed until the Hayashi limit is reached, and thereafter contraction will continue on a Kelvin–Helmholtz timescale with the temperature remaining stable. Stars with less than 0.5  M ☉ thereafter join

612-471: Is a blue-white hued star of magnitude 6.1. The two stars are distinguishable in binoculars. β Capricorni's traditional name comes from the Arabic phrase for "the lucky stars of the slaughterer," a reference to ritual sacrifices performed by ancient Arabs at the heliacal rising of Capricornus. Another star visible to the naked eye is γ Capricorni , sometimes called Nashira ("bringing good tidings"); it

680-492: Is a globular cluster located 1 degree south of the galaxy group that contains NGC 7103 . The constellation also harbors the wide spiral galaxy NGC 6907 . Messier 30 (NGC 7099) is a centrally-condensed globular cluster of magnitude 7.5 . At a distance of 30,000 light-years, it has chains of stars extending to the north that are resolvable in small amateur telescopes. One galaxy group located in Capricornus

748-426: Is a multiple star. The primary ( α Cap ), 109 light-years from Earth, is a yellow-hued giant star of magnitude 3.6; the secondary ( α Cap ), 690 light-years from Earth, is a yellow-hued supergiant star of magnitude 4.3. The two stars are distinguishable by the naked eye, and both are themselves multiple stars. α Capricorni is accompanied by a star of magnitude 9.2; α Capricorni

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816-399: Is a white-hued giant star of magnitude 3.7, 139 light-years from Earth. π Capricorni is a double star with a blue-white hued primary of magnitude 5.1 and a white-hued secondary of magnitude 8.3. It is 670 light-years from Earth and the components are distinguishable in a small telescope. Several galaxies and star clusters are contained within Capricornus. Messier 30

884-500: Is about 100–100,000 times stronger than X-ray emission from main-sequence stars. The earliest detections of X-rays from T Tauri stars were made by the Einstein X-ray Observatory . For low-mass stars X-rays are generated by the heating of the stellar corona through magnetic reconnection , while for high-mass O and early B-type stars X-rays are generated through supersonic shocks in the stellar winds. Photons in

952-444: Is accompanied by a star of magnitude 11.0; this faint star is itself a binary star with two components of magnitude 11. Also called Algedi or Giedi, the traditional names of α Capricorni come from the Arabic word for "the kid", which references the constellation's mythology. β Capricorni is a double star also known as Dabih. It is a yellow-hued giant star of magnitude 3.1, 340 light-years from Earth. The secondary

1020-535: Is capitalised: CMa for Canis Major , CMi for Canis Minor . Two cases are ambiguous: Leo for the constellation Leo could be mistaken for Leo Minor (abbreviated LMi ), and Tri for Triangulum could be mistaken for Triangulum Australe (abbreviated TrA ). In addition to the three-letter abbreviations used today, the IAU also introduced four-letter abbreviations in 1932. The four-letter abbreviations were repealed in 1955 and are now obsolete, but were included in

1088-548: Is named for the Arabic word for "tail or end" ( deneb ) and “young goat / kid” (al-gedi); its traditional name means "tail to head” or “back to the beginning", which could be related to the Ouroboros or Janus since the zodiac relates to January. Deneb Algedi is a Beta Lyrae variable star (a type of eclipsing binary ). It ranges by about 0.2 magnitudes with a period of 24.5 hours. The other bright stars in Capricornus range in magnitude from 3.1 to 5.1. α Capricorni

1156-401: Is nearly complete, the resulting object is known as a protostar . Accretion of material onto the protostar continues partially from the newly formed circumstellar disc . When the density and temperature are high enough, deuterium fusion begins, and the outward pressure of the resultant radiation slows (but does not stop) the collapse. Material comprising the cloud continues to "rain" onto

1224-618: Is observable in so-called embedded clusters . The end product of a core collapse is an open cluster of stars. In triggered star formation , one of several events might occur to compress a molecular cloud and initiate its gravitational collapse . Molecular clouds may collide with each other, or a nearby supernova explosion can be a trigger, sending shocked matter into the cloud at very high speeds. (The resulting new stars may themselves soon produce supernovae, producing self-propagating star formation .) Alternatively, galactic collisions can trigger massive starbursts of star formation as

1292-410: Is primarily lost through radiation. However, the collapsing cloud will eventually become opaque to its own radiation, and the energy must be removed through some other means. The dust within the cloud becomes heated to temperatures of 60–100 K , and these particles radiate at wavelengths in the far infrared where the cloud is transparent. Thus the dust mediates the further collapse of the cloud. During

1360-403: Is sufficiently transparent to allow energy radiated by the protostar to escape. The combination of convection within the protostar and radiation from its exterior allow the star to contract further. This continues until the gas is hot enough for the internal pressure to support the protostar against further gravitational collapse—a state called hydrostatic equilibrium . When this accretion phase

1428-592: The Babylonian star catalogues before 1000 BCE. In the Early Bronze Age the winter solstice occurred in the constellation, but due to the precession of the equinoxes , the December solstice now takes place in the constellation Sagittarius . The Sun is now in the constellation Capricorn (as distinct from the astrological sign) from late January through mid-February. Although the solstice during

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1496-401: The Big Bang , are widespread throughout the universe, and are associated with new stars and exoplanets . In February 2018, astronomers reported, for the first time, a signal of the reionization epoch, an indirect detection of light from the earliest stars formed - about 180 million years after the Big Bang . An article published on October 22, 2019, reported on the detection of 3MM-1 ,

1564-560: The Orion Nebula Cluster and Taurus Molecular Cloud . The formation of individual stars can only be directly observed in the Milky Way Galaxy , but in distant galaxies star formation has been detected through its unique spectral signature . Initial research indicates star-forming clumps start as giant, dense areas in turbulent gas-rich matter in young galaxies, live about 500 million years, and may migrate to

1632-620: The Society Islands , the figure of Capricornus was called Rua-o-Mere , "Cavern of parental yearnings". In Indian astronomy and Indian astrology , it is called Makara , the crocodile. 88 modern constellations In contemporary astronomy , 88 constellations are recognized by the International Astronomical Union (IAU). Each constellation is a region of the sky bordered by arcs of right ascension and declination , together covering

1700-496: The Wide-field Infrared Survey Explorer (WISE) have thus been especially important for unveiling numerous galactic protostars and their parent star clusters . Examples of such embedded star clusters are FSR 1184, FSR 1190, Camargo 14, Camargo 74, Majaess 64, and Majaess 98. The structure of the molecular cloud and the effects of the protostar can be observed in near-IR extinction maps (where

1768-644: The genitive form of the constellation name. As the genitive is similar to the base name, the majority of the abbreviations are just the first three letters of the constellation name: Ori for Orion/Orionis , Ara for Ara/Arae , and Com for Coma Berenices/Comae Berenices . In some cases, the abbreviation contains letters from the genitive not appearing in the base name (as in Hyi for Hydrus/Hydri , to avoid confusion with Hydra , abbreviated Hya ; and Sge for Sagitta/Sagittae , to avoid confusion with Sagittarius , abbreviated Sgr ). Some abbreviations use letters beyond

1836-484: The optical . The protostellar stage of stellar existence is almost invariably hidden away deep inside dense clouds of gas and dust left over from the GMC . Often, these star-forming cocoons known as Bok globules , can be seen in silhouette against bright emission from surrounding gas. Early stages of a star's life can be seen in infrared light, which penetrates the dust more easily than visible light. Observations from

1904-407: The protostar . In this stage bipolar jets are produced called Herbig–Haro objects . This is probably the means by which excess angular momentum of the infalling material is expelled, allowing the star to continue to form. When the surrounding gas and dust envelope disperses and accretion process stops, the star is considered a pre-main-sequence star (PMS star). The energy source of these objects

1972-478: The ρ Ophiuchi cloud complex . A more compact site of star formation is the opaque clouds of dense gas and dust known as Bok globules , so named after the astronomer Bart Bok . These can form in association with collapsing molecular clouds or possibly independently. The Bok globules are typically up to a light-year across and contain a few solar masses . They can be observed as dark clouds silhouetted against bright emission nebulae or background stars. Over half

2040-668: The 88 constellations so that every point in the sky belonged to one constellation. Some constellations are no longer recognized by the IAU, but may appear in older star charts and other references. Most notable is Argo Navis , which was one of Ptolemy's original 48 constellations. In the 1750s the French astronomer Nicolas Louis de Lacaille divided this into three separate constellations: Carina , Puppis , and Vela . The 88 constellations depict 42 animals, 29 inanimate objects, and 17 humans or mythological characters. Each IAU constellation has an official three-letter abbreviation based on

2108-626: The California GMC follow power-law distributions at the high-mass end, consistent with the Salpeter initial mass function (IMF). Current results strongly support the existence of a connection between the FLMF and the CMF/IMF, demonstrating that this connection holds at the level of an individual cloud, specifically the California GMC. The FLMF presented is a distribution of local line masses for

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2176-476: The Milky Way contain stars , stellar remnants , and a diffuse interstellar medium (ISM) of gas and dust. The interstellar medium consists of 10 to 10 particles per cm , and is typically composed of roughly 70% hydrogen , 28% helium , and 1.5% heavier elements by mass. The trace amounts of heavier elements were and are produced within stars via stellar nucleosynthesis and ejected as the stars pass beyond

2244-588: The NASA Dictionary of Technical Terms for Aerospace Use (NASA SP-7) published in 1965. These are labeled "NASA" in the table below and are included here for reference only. For help with the literary English pronunciations, see the pronunciation key . There is considerable diversity in how Latinate names are pronounced in English. For traditions closer to the original, see Latin spelling and pronunciation . Various other unofficial patterns exist alongside

2312-541: The Water, consisting of many water-related constellations such as Aquarius, Pisces and Eridanus . It is the smallest constellation in the zodiac. Capricornus is a faint constellation, with only one star above magnitude 3; its alpha star has a magnitude of only 3.6. The brightest star in Capricornus is δ Capricorni , also called Deneb Algedi, with a magnitude of 2.9, located 39 light-years from Earth. Like several other stars such as Denebola and Deneb , it

2380-414: The center of a galaxy, creating the central bulge of a galaxy. On February 21, 2014, NASA announced a greatly upgraded database for tracking polycyclic aromatic hydrocarbons (PAHs) in the universe . According to scientists, more than 20% of the carbon in the universe may be associated with PAHs, possible starting materials for the formation of life . PAHs seem to have been formed shortly after

2448-505: The cloud in which the star is forming is usually too big to allow us to observe it in the visual part of the spectrum. This presents considerable difficulties as the Earth's atmosphere is almost entirely opaque from 20μm to 850μm, with narrow windows at 200μm and 450μm. Even outside this range, atmospheric subtraction techniques must be used. X-ray observations have proven useful for studying young stars, since X-ray emission from these objects

2516-430: The clouds dissipate. Giant molecular clouds, which are generally warmer, produce stars of all masses. These giant molecular clouds have typical densities of 100 particles per cm , diameters of 100 light-years (9.5 × 10   km ), masses of up to 6 million solar masses ( M ☉ ) , or six million times the mass of Earth's sun. The average interior temperature is 10  K (−441.7  °F ). About half

2584-455: The collapse, the density of the cloud increases towards the center and thus the middle region becomes optically opaque first. This occurs when the density is about 10 g / cm . A core region, called the first hydrostatic core, forms where the collapse is essentially halted. It continues to increase in temperature as determined by the virial theorem. The gas falling toward this opaque region collides with it and creates shock waves that further heat

2652-559: The confines of Aquarius at the time of its discovery). Despite its faintness, the constellation Capricornus has one of the oldest mythological associations, having been consistently represented as a hybrid of a goat and a fish since the Middle Bronze Age , when the Babylonians used SUḪUR.MAŠ "The Goat-Fish" as a symbol of their god Ea . In Greek mythology , the constellation is sometimes identified as Amalthea ,

2720-609: The constellations. These are known as "asterisms". Examples include the Big Dipper /Plough and the Northern Cross . Some ancient asterisms, for example Coma Berenices , Serpens , and portions of Argo Navis , are now officially constellations. Star formation Star formation is the process by which dense regions within molecular clouds in interstellar space , sometimes referred to as "stellar nurseries" or " star -forming regions", collapse and form stars . As

2788-425: The core. When the core temperature reaches about 2000 K , the thermal energy dissociates the H 2 molecules. This is followed by the ionization of the hydrogen and helium atoms. These processes absorb the energy of the contraction, allowing it to continue on timescales comparable to the period of collapse at free fall velocities. After the density of infalling material has reached about 10 g / cm , that material

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2856-498: The dense nebulae where stars are produced, much of the hydrogen is in the molecular (H 2 ) form, so these nebulae are called molecular clouds . The Herschel Space Observatory has revealed that filaments, or elongated dense gas structures, are truly ubiquitous in molecular clouds and central to the star formation process. They fragment into gravitationally bound cores, most of which will evolve into stars. Continuous accretion of gas, geometrical bending , and magnetic fields may control

2924-428: The detailed manner in which the filaments are fragmented. Observations of supercritical filaments have revealed quasi-periodic chains of dense cores with spacing comparable to the filament inner width, and embedded protostars with outflows. Observations indicate that the coldest clouds tend to form low-mass stars, which are first observed via the infrared light they emit inside the clouds, and then as visible light when

2992-410: The disk and onto the protostar. Present thinking is that massive stars may therefore be able to form by a mechanism similar to that by which low mass stars form. There is mounting evidence that at least some massive protostars are indeed surrounded by accretion disks. Disk accretion in high-mass protostars, similar to their low-mass counterparts, is expected to exhibit bursts of episodic accretion as

3060-418: The edge-on spiral galaxy, both of which have active nuclei , are connected by a stream of stars and dust, indicating that they too are interacting. Astronomers predict that the three galaxies may merge millions of years in the future to form a giant elliptical galaxy. The constellation was first attested in depictions on a cylinder-seal from around the 21st century BCE, it was explicitly recorded in

3128-420: The effects of turbulence , macroscopic flows, rotation , magnetic fields and the cloud geometry. Both rotation and magnetic fields can hinder the collapse of a cloud. Turbulence is instrumental in causing fragmentation of the cloud, and on the smallest scales it promotes collapse. A protostellar cloud will continue to collapse as long as the gravitational binding energy can be eliminated. This excess energy

3196-408: The end of their main sequence lifetime. Higher density regions of the interstellar medium form clouds, or diffuse nebulae , where star formation takes place. In contrast to spiral galaxies, elliptical galaxies lose the cold component of its interstellar medium within roughly a billion years, which hinders the galaxy from forming diffuse nebulae except through mergers with other galaxies. In

3264-405: The energy gained by the release of gravitational potential energy . As the density increases, the fragments become opaque and are thus less efficient at radiating away their energy. This raises the temperature of the cloud and inhibits further fragmentation. The fragments now condense into rotating spheres of gas that serve as stellar embryos. Complicating this picture of a collapsing cloud are

3332-614: The entire celestial sphere . Their boundaries were officially adopted by the International Astronomical Union in 1928 and published in 1930. The ancient Mesopotamians and later the Greeks established most of the northern constellations in international use today, listed by the Roman-Egyptian astronomer Ptolemy . The constellations along the ecliptic are called the zodiac . When explorers mapped

3400-486: The entire parent molecular cloud, instead of simply from a small local region. Another theory of massive star formation suggests that massive stars may form by the coalescence of two or more stars of lower mass. Recent studies have emphasized the role of filamentary structures in molecular clouds as the initial conditions for star formation. Findings from the Herschel Space Observatory highlight

3468-409: The formation of new stars in aging galaxies. However, the radio emissions around the jets may also trigger star formation. Likewise, a weaker jet may trigger star formation when it collides with a cloud. As it collapses, a molecular cloud breaks into smaller and smaller pieces in a hierarchical manner, until the fragments reach stellar mass. In each of these fragments, the collapsing gas radiates away

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3536-557: The gas clouds in each galaxy are compressed and agitated by tidal forces . The latter mechanism may be responsible for the formation of globular clusters . A supermassive black hole at the core of a galaxy may serve to regulate the rate of star formation in a galactic nucleus. A black hole that is accreting infalling matter can become active , emitting a strong wind through a collimated relativistic jet . This can limit further star formation. Massive black holes ejecting radio-frequency-emitting particles at near-light speed can also block

3604-438: The goat that suckled the infant Zeus after his mother, Rhea , saved him from being devoured by his father, Cronos . Amalthea's broken horn was transformed into the cornucopia or "horn of plenty". Capricornus is also sometimes identified as Pan , the god with a goat's horns and legs, who saved himself from the monster Typhon by giving himself a fish's tail and diving into a river. Capricornus's brighter stars are found on

3672-488: The gravitational collapse of rotating density enhancements within molecular clouds. As described above, the collapse of a rotating cloud of gas and dust leads to the formation of an accretion disk through which matter is channeled onto a central protostar. For stars with masses higher than about 8  M ☉ , however, the mechanism of star formation is not well understood. Massive stars emit copious quantities of radiation which pushes against infalling material. In

3740-412: The initial three to unambiguously identify the constellation (for example when the name and its genitive differ in the first three letters): Aps for Apus/Apodis , CrA for Corona Australis , CrB for Corona Borealis , Crv for Corvus . ( Crater is abbreviated Crt to prevent confusion with CrA .) When letters are taken from the second word of a two-word name, the first letter from the second word

3808-527: The internal thermal energy. If a cloud is massive enough that the gas pressure is insufficient to support it, the cloud will undergo gravitational collapse . The mass above which a cloud will undergo such collapse is called the Jeans mass . The Jeans mass depends on the temperature and density of the cloud, but is typically thousands to tens of thousands of solar masses. During cloud collapse dozens to tens of thousands of stars form more or less simultaneously which

3876-436: The known Bok globules have been found to contain newly forming stars. An interstellar cloud of gas will remain in hydrostatic equilibrium as long as the kinetic energy of the gas pressure is in balance with the potential energy of the internal gravitational force . Mathematically this is expressed using the virial theorem , which states that, to maintain equilibrium, the gravitational potential energy must equal twice

3944-553: The main sequence. For more massive PMS stars, at the end of the Hayashi track they will slowly collapse in near hydrostatic equilibrium, following the Henyey track . Finally, hydrogen begins to fuse in the core of the star, and the rest of the enveloping material is cleared away. This ends the protostellar phase and begins the star's main sequence phase on the H–R diagram. The stages of

4012-451: The northern hemisphere's winter no longer takes place while the sun is in the constellation Capricornus, as it did until 130 BCE, the astrological sign called Capricorn is still used to denote the position of the solstice, and the latitude of the sun's most southerly position continues to be called the Tropic of Capricorn , a term which also applies to the line on the Earth at which

4080-401: The number of stars are counted per unit area and compared to a nearby zero extinction area of sky), continuum dust emission and rotational transitions of CO and other molecules; these last two are observed in the millimeter and submillimeter range. The radiation from the protostar and early star has to be observed in infrared astronomy wavelengths, as the extinction caused by the rest of

4148-413: The past, it was thought that this radiation pressure might be substantial enough to halt accretion onto the massive protostar and prevent the formation of stars with masses more than a few tens of solar masses. Recent theoretical work has shown that the production of a jet and outflow clears a cavity through which much of the radiation from a massive protostar can escape without hindering accretion through

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4216-420: The process are well defined in stars with masses around 1  M ☉ or less. In high mass stars, the length of the star formation process is comparable to the other timescales of their evolution, much shorter, and the process is not so well defined. The later evolution of stars is studied in stellar evolution . Key elements of star formation are only available by observing in wavelengths other than

4284-675: The soft X-ray energy range covered by the Chandra X-ray Observatory and XMM-Newton may penetrate the interstellar medium with only moderate absorption due to gas, making the X-ray a useful wavelength for seeing the stellar populations within molecular clouds. X-ray emission as evidence of stellar youth makes this band particularly useful for performing censuses of stars in star-forming regions, given that not all young stars have infrared excesses. X-ray observations have provided near-complete censuses of all stellar-mass objects in

4352-458: The stars of the southern skies, European astronomers proposed new constellations for that region, as well as ones to fill gaps between the traditional constellations. Because of their Roman and European origins, every constellation has a Latin name. In 1922, the International Astronomical Union adopted three-letter abbreviations for 89 constellations, the modern list of 88 plus Argo . After this, Eugène Joseph Delporte drew up boundaries for each of

4420-519: The sun is directly overhead at local noon on the day of the December solstice. The planet Neptune was discovered by German astronomer Johann Galle , near Deneb Algedi (δ Capricorni) on 23 September 1846, as Capricornus can be seen best from Europe at 4:00 AM in September (although, by modern constellation boundaries established in the early 20th century CE, Neptune lay within

4488-595: The tip of the horn, is of the third magnitude. The goat's tail consists of stars β Cap and α Cap: star β Cap being of the third magnitude. The goat's hind foot consists of stars ψ Cap and ω Cap. Both of these stars are of the fourth magnitude. In Chinese astronomy , constellation Capricornus lies in The Black Tortoise of the North ( 北方玄武 ; Běi Fāng Xuán Wǔ ). The Nakh peoples called this constellation Roofing Towers ( Chechen : Neģara Bjovnaš ). In

4556-522: The total mass of the Milky Way 's galactic ISM is found in molecular clouds and the galaxy includes an estimated 6,000 molecular clouds, each with more than 100,000  M ☉ . The nebula nearest to the Sun where massive stars are being formed is the Orion Nebula , 1,300 light-years (1.2 × 10  km) away. However, lower mass star formation is occurring about 400–450 light-years distant in

4624-460: The ubiquitous nature of these filaments in the cold interstellar medium (ISM). The spatial relationship between cores and filaments indicates that the majority of prestellar cores are located within 0.1 pc of supercritical filaments. This supports the hypothesis that filamentary structures act as pathways for the accumulation of gas and dust, leading to core formation. Both the core mass function (CMF) and filament line mass function (FLMF) observed in

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