Hercules is the fifth largest constellation, but has no first magnitude stars. It occupies an area of 1225 square degrees in the sky. The constellation lies in the third quadrant of the northern hemisphere (NQ3) and can be seen at latitudes between +90° and -50°. The neighboring constellations are Aquila, Boötes, Corona Borealis, Draco, Lyra, Ophiuchus, Sagitta, Serpens Caput and Vulpecula.
[http://www.constellation-guide.com/constellation-list/hercules-constellation/]
Johannes Hevelius’ Herculese from Uranographia (1690)
Hercules, the son of Alcmene and Zeus, is known for his bravery that placed him among the gods on Mount Olympus. Before Hercules was conceived, his father, Zeus, was known as an unfaithful husband. He fell in love with Alcmene and, in turn, a child was born. Alcmene named him Hercules, which literally means ‘glorious gift of Hera.’ Zeus’ wife, Hera, was enraged. She attempted to kill Hercules by placing snakes in Hercules’s crib, but this failed as Hercules strangled the snakes with his bare hands.
Hera, the queen of the gods, knew that she was not strong enough to fight Hercules. Therefore, she decided to get revenge for Zeus’ actions by making Hercules’s life as miserable as anyone could imagine. As Hercules grew, he became a legendary warrior and fell in love with a woman named Magera. They married and had two children, and they lived happily together. Hera, who kept to her plans of misery, instilled a wild rage in Hercules which caused him to kill his family.
When the blaze of madness departed, Hercules realized the bloody atrocity that he committed and prayed to the Delphic oracle, Apollo. Apollo said to Hercules that he must complete 10 tasks, which increased to 12 later on, as punishment to cleanse his soul. Hera continued to make life difficult for Hercules while he completed the 12 adventures. Later on, Apollo told Hercules that he would not pass in to the underworld, but would become a god.
Hercules’s ascendance to Mount Olympus started when his second and beautiful wife, Deianira, gave him a cloak that she wove herself. In the cloak she smeared a magical balm that a centaur had given her and said that anyone who wore the balm would love her forever. Unfortunately, this was not true and when Hercules put on the cloak he began to burn with severe pain. When he tried to take the cloak off, the pain only became worse and he thought he would die. He asked his friends to build a pyre on Mount Oeta and to light it as he lay on it. But, in the meantime, Zeus had been able to convince Hera that Hercules had gone through enough pain to satiate her anger. She agreed with his argument, and Zeus then sent Athena to recover Hercules and bring him to his new home on Mount Olympus.
[http://chandra.harvard.edu/photo/constellations/hercules.html]
According to Gavin White, the Greek constellation of Hercules is a distorted version of the Babylonian constellation known as the ‘Standing Gods’ (MUL.DINGIR.GUB.BA.MESH). White argues that this figure was, like the similarly named ‘Sitting Gods,’ depicted as a man with a serpent’s body instead of legs (the serpent element now being represented on the Greek star map by the figure of Draco that Hercules crushes beneath his feet). He further argues that the original name of Hercules is a conflation of the two Babylonian constellations of the Sitting and Standing Gods. Hercules is also sometimes associated with Gilgamesh, a Sumerian mythological a hero.
In Chinese astronomy, the stars that correspond to Hercules are located in two areas: the Purple Forbidden enclosure (Zǐ Wēi Yuán) and the Heavenly Market enclosure (Tiān Shì Yuán).
[https://www.astronomytrek.com/star-constellation-facts-hercules/]
Traditional view of the Hercules constellation highlighting the quadrangle which forms the Keystone asterism.
The traditional visualization imagines α Herculis as Hercules’s head. Hercules’s left hand then points toward Lyra from his shoulder (δ Herculis), and β Herculis forms his other shoulder. His narrow waist is formed by ε Herculis and ζ Herculis. Finally, his left leg (with θ Herculis as the knee and ι Herculis the foot) is stepping on Draco’s head, the dragon/snake who Hercules has vanquished and perpetually gloats over for eternities.
A common form found in modern star charts uses the quadrangle formed by π Her, η Her, ζ Her and ε Her (known as the ‘Keystone’ asterism) as Hercules’s torso.
Hercules has no first or second magnitude stars. However, it does have several stars above magnitude 4.
Kornephoros (Beta Herculis)
[http://www.nikomi.net/english/art/photo/astro/stars/kornephoros.htm]
Beta Herculis, also named Kornephoros, from a Greek word meaning ‘club bearer,’ is a binary star and the brightest star in the northern constellation of Hercules at a base apparent visual magnitude of 2.81. This is a suspected variable star with an apparent magnitude that may rise as high as 2.76. Based upon parallax measurements, it is located at a distance of 139 light-years (43 parsecs) from the Sun.
Although Beta Herculis appears to the naked eye to be a single star, in July 1899 the American astronomer W. W. Campbell discovered from spectroscopic measurements that its radial velocity varies, and concluded that it has a companion.
The primary star has a stellar classification of G7 IIIa, indicating that it is a giant star that has exhausted the hydrogen at its core and evolved away from the main sequence. It has a mass nearly three times the mass of the Sun, and has expanded to 17 times the Sun’s radius. The effective temperature of the star’s outer envelope is about 4,887 K, which gives it the yellow hue of a G-type star. The secondary star has a mass 90% that of the Sun.
[https://en.wikipedia.org/wiki/Beta_Herculis]
[http://www.sciencecenter.net/whatsup/08/h-stars.htm]
Zeta Herculis is a multiple star system in the constellation Hercules. It has a combined apparent visual magnitude of 2.81, which is readily visible to the naked eye. Parallax measurements put it at a distance of about 35.0 light-years (10.7 parsecs) from Earth.
The primary member is a subgiant star that is somewhat larger than the Sun and has just begun to evolve away from the main sequence as the supply of hydrogen at its core becomes exhausted. It is orbited by a smaller companion star at a mean angular separation of 1.5 arcseconds, which corresponds to a physical separation of about 15 Astronomical Units. This distance is large enough so that the two stars do not have a significant tidal effect on each other. The stars orbit each other over a period of 34.45 years, with a semi-major axis of 1.33" and an eccentricity of 0.46.
Component A has a stellar classification of F9 IV. It has about 2.6 times the radius of the Sun and 1.45 times the Sun’s mass. This star is radiating more than six times the luminosity of the Sun at an effective temperature of 5,820 K. The secondary component (Component B) is about the same size and mass as the Sun, with an effective temperature of 5,300 K. Both stars are rotating slowly. There may be a faint third member of this system, although little is known about it.
[https://en.wikipedia.org/wiki/Zeta_Herculis]
In this STScI photo of Delta (δ) Herculis, the central glow and the inner ring of stars is obvious. The outer ring is a bit subdued, but is easier to see if you click on the image and enlarge it. The secondary is lost here in the glare of the primary.
[https://bestdoubles.wordpress.com/2011/07/16/surrounded-by-a-ring-of-white-fire-delta-%CE%B4-herculis/]
δ Herculis bore the traditional name Sarin. It is a complex star system consisting of at least two stars and possibly as many as five. The main star is an A-type main-sequence subgiant with a stellar classification A3IV. The subgiant has both a mass and radius that are roughly two times solar yielding a total luminosity of about 18.5 L☉. Though it only shines with an apparent magnitude of 3.12, it the third-brightest star in the Hercules constellation. The most recent Hipparcos data yields a distance estimate of approximately 23.1 parsecs (75 light-years) from Earth.
[https://en.wikipedia.org/wiki/Delta_Herculis]
The star Pi Herculis, rendered with Celestia software, as it might appear from 3 Astronomical Units away.
Pi Herculis is a third-magnitude star in the constellation Hercules. As one of the four stars in the Keystone asterism is one of the more easily recognized in the constellation. It has an apparent visual magnitude of +3.2, which is visible to the naked eye and makes it one of the brighter members of the constellation. Its distance is estimated at roughly 115 parsecs from Earth, or about 377 light years away.
It is a bright giant star with a stellar classification of K3 II. The star is enormous compared to the Sun, having a mass that is 4.5 times solar and a radius approximately 60 times depending on which wavelength the star’s angular diameter is measured at. Due to limb darkening, all giant and supergiant stars present unique challenges when measuring their photosphere. This orange-hued giant shines with 1,330 times the luminosity of the Sun. It is a low-amplitude photometric variable star showing a typical change of roughly 0.0054 in magnitude over a 24-hour period.
Low-amplitude radial velocity variations with a period of 613 days in the bright giant have suggested the possible presence of a substellar companion. If this is really due to a low-mass object, such a companion would be as small as 0.027 Solar masses (27 times the mass of Jupiter, probably a brown dwarf) and 3 astronomical units away from the bright primary. A substellar companion is only one of several hypotheses to explain the star’s behavior. Most likely the cause of the variation is weak pulsation of the star’s atmosphere.
[https://en.wikipedia.org/wiki/Pi_Herculis]
Rasalgethi
[http://oneminuteastronomer.com/4132/rasalgethi/]
Alpha Herculis, also designated 64 Herculis, is a multiple star system in the constellation of Hercules. The system bore the traditional name Rasalgethi or Ras Algethi (‘Head of the Kneeler’ in Arabic).
When viewed through a telescope, this system is resolved into a number of components. The two components are designated α¹ Herculis (the brightest of the two) and α² Herculis. The latter is itself a binary star and all three stars are sometimes designated α Herculis A, Ba and Bb, respectively.
α1 and α² Herculis are more than 500 astronomical units apart, with an estimated orbital period of approximately 3600 years. α¹ is a relatively massive red bright giant. α²’s two components are a primary yellow giant star and a secondary, yellow-white dwarf star in a 51.578 day orbit.
α1 Herculis is an asymptotic giant branch (AGB) star, a luminous red giant that has both hydrogen and helium shells around a degenerate carbon-oxygen core. Its angular diameter has been measured with an interferometer as 34 ± 0.8 mas, or 0.034 arcseconds. At an estimated distance of 110 parsecs from the Sun, this corresponds to a radius of about 280 million kilometers (or 170 million miles), which is roughly 400 R☉ or 1.87 AU. If Rasalgethi were at the center of the Solar System its radius would extend past the orbit of Mars at 1.5 AU but not quite as far as the asteroid belt. The red giant is estimated to have started its life with about 2.175-3.250 M☉.
Like most type M stars near the end of their lives, Rasalgethi is experiencing a high degree of stellar mass loss creating a sparse, gaseous envelope that extends at least 90 astronomical units.
[https://en.wikipedia.org/wiki/Alpha_Herculis]
Mu Herculis
[http://www.seetheglory.com/double-star-mu-herculis/]
Mu Herculis is a nearby star system about 27.1 light years from Earth in the constellation Hercules. Its main star, Mu Herculis A is fairly similar to the Sun although more highly evolved with a stellar classification of G5 IV. Its mass is about 1.1 times that of the Sun, and it is beginning to expand to become a giant.
The secondary component consists of a pair of stars that orbit about each other with a period of 43.2 years. Mu Herculis A and the binary pair B-C are separated by 286 AUs. The stars B-C are separated from each other by 11.4 AUs. Their orbit is quite elliptic (e=0.18) and both stars swing each other between 9.4 and 13.5 AUs.
Star A is itself suspected to be a close binary with a low mass stellar or a large substellar companion, probably at 17.2 AU in an elliptic orbit. Nevertheless, the existence of such an object has still not been confirmed.
[https://en.wikipedia.org/wiki/Mu_Herculis]
Gliese 623 is a dim double star 26.3 light years from Earth in the constellation Hercules. It was photographed by the NASA/ESA Hubble Space Telescope’s Faint Object Camera in 1994. The binary system consists of two red dwarfs orbiting each other at a distance of 1.9 astronomical units:
[https://en.wikipedia.org/wiki/Gliese_623]
Gliese 623B
This ESA/NASA Hubble Space Telescope picture resolves, for the first time, one of the smallest stars in our Milky Way Galaxy. Called Gliese 623b or Gl623b, the diminutive star (right of center) is ten times less massive than the Sun and 60 000 times fainter. (If it were as far away as the Sun, it would be only eight times brighter than the full Moon).
Located 25 light-years away in the constellation Hercules, Gl623b is the smaller component of a double star system, where the separation between the two members is only twice the distance between Earth and the Sun (approximately 200 million miles). The small star completes one orbit about its larger companion every four years.
Gl623b was first detected, indirectly, from astrometric observations that measured the wobble of the primary star due to the gravitational pull of its smaller, unseen companion. However, the star is too dim and too close to its companion star to be seen by ground-based telescopes. Hubble’s view is sharp enough to separate the small star from its companion.
The new Hubble observations will allow astronomers to measure the intrinsic brightness and mass of Gl623b. This will lead to a better understanding of the formation and evolution of the smallest stars currently known. Red dwarf stars were once thought to be the most abundant stars in the Milky Way, and thus possibly a solution to the mystery of the Galaxy’s ‘dark matter.’ However, recent Hubble observations show that these low mass stars are surprisingly rare.
The image was taken in visible light on June 11, 1994, with the European Space Agency’s Faint Object Camera.
[http://sci.esa.int/hubble/36857-gliese-623b/]
DQ Herculis (or Nova Herculis 1934) was a slow, bright nova occurring in Hercules in December 1934. The nova was first observed on 13 Dec, 1934, reaching a peak brightness with an apparent magnitude 1.5 on 22 Dec, 1934. The nova remained visible to the naked eye for several months.
DQ Herculis is the prototype for a category of cataclysmic variable stars called intermediate polars. The system shows orbital period variation, possibly due to the presence of a third body:
[https://en.wikipedia.org/wiki/DQ_Herculis]
DQ Herculis: Nova 1934
Nova Herculis 1934 was discovered by Manning Prentice- then Director of the BAA Meteor section- on the night of December 12th at magnitude 3.4 following a long session observing meteors. The nova peaked 9 days later at magnitude 1.5. A slow fade followed, with the nova losing 3 magnitudes in 94 days, followed by a more rapid decline of 8 magnitudes in just one month. DQ Her then brightened once more to reach a second fainter maximum of 6.5, which was then followed by a long slow decline to minimum.
DQ Her is now known to belong to the group of CVs known as Intermediate Polars. These binary systems consist of a red star and fast rotating (72 seconds for DQ Her) highly magnetic white dwarf, whose orbital periods lie above the period gap (>3h). Intermediate Polars resemble their close cousins the AM Her type stars in many ways, except that the latter are spin/orbit synchronized, and generally have shorter orbital periods which prevents the formation of an accretion disk.
[http://www.britastro.org/vss/00191a.html]
POSSII image of HD 164595 in near infrared
[https://disownedsky.blogspot.gr/2016/08/the-possible-seti-target-hd-164595.html]
HD 164595 is a G-type star located in the constellation of Hercules, 28.927 parsecs (94.35 light-years) from Earth. With an apparent magnitude of 7.075, the star can be found with binoculars or a small telescope. It is the same stellar classification as the Sun: G2V. It has a similar temperature, at 5790 K compared with 5778 K for the Sun. It has a lower logarithm of metallicity ratio, at −0.06 compared with 0.00, and a slightly younger age, at 4.5 versus 4.6 billion years.
HD 164595 has one known planet, HD 164595 b, which orbits HD 164595 every 40 days. The planet has a mass equivalent of 16 Earths.
In 2016, HD 164595 briefly attracted media attention after it was reported that a possible SETI signal had been detected from the direction of the star in the previous year. The signal was only heard once and never confirmed by other telescopes, and is thought to have been due to terrestrial interference.
[https://en.wikipedia.org/wiki/HD_164595]
Hercules contains two bright globular clusters: M13, the brightest globular cluster in the northern hemisphere, and M92. M13 lies between the stars η Her and ζ Her; it is dim, but it is visible to both the naked eye and binoculars. It is a globular cluster of the 6th magnitude that contains more than 300,000 stars. It is also very large, with an apparent diameter of over 0.25 degrees, half the size of the full moon; its physical diameter is more than 100 light-years. Individual stars in M13 are resolvable in a small amateur telescope:
M13: The Great Globular Cluster in Hercules
In 1716, English astronomer Edmond Halley noted, “This is but a little Patch, but it shews itself to the naked Eye, when the Sky is serene and the Moon absent.” Of course, M13 is now modestly recognized as the Great Globular Cluster in Hercules, one of the brightest globular star clusters in the northern sky. Telescopic views reveal the spectacular cluster’s hundreds of thousands of stars. At a distance of 25,000 light-years, the cluster stars crowd into a region 150 light-years in diameter, but approaching the cluster core upwards of 100 stars could be contained in a cube just 3 light-years on a side. For comparison, the closest star to the Sun is over 4 light-years away. Along with the cluster’s dense core, the outer reaches of M13 are highlighted in this sharp color image. The cluster’s evolved red and blue giant stars show up in yellowish and blue tints.
[https://apod.nasa.gov/apod/ap120614.html]
M92 is a globular cluster of magnitude 6.4, 26,000 light-years from earth. It is a Shapley class IV cluster, indicating that it is quite concentrated at the center; it has a very clear nucleus. M92 is visible as a fuzzy star in binoculars, like M13; it is denser and smaller than the more celebrated cluster. The oldest globular cluster known at 14 billion years, its stars are resolvable in a medium-aperture amateur telescope:
Comet Garradd and M92
Sweeping slowly through the constellation Hercules, Comet Garradd (C2009/P1) passed with about 0.5 degrees of globular star cluster M92 on February 3. Captured here in its latest Messier moment, the steady performer remains just below naked-eye visibility with a central coma comparable in brightness to the dense, well-known star cluster. The rich telescopic view from New Mexico’s, early morning skies, also features Garradd’s broad fan shaped dust tail and a much narrower ion tail that extends up and beyond the right edge of the frame. Pushed out by the pressure of sunlight, the dust tail tends to trail the comet along its orbit while the ion tail, blown by the solar wind, streams away from the comet in the direction opposite the Sun. Of course, M92 is over 25,000 light-years away. Comet Garradd is 12.5 light-minutes from planet Earth, arcing above the ecliptic plane.
[https://apod.nasa.gov/apod/ap120204.html]
Hercules also contains the nearly spherical planetary nebula Abell 39. It is a low surface brightness planetary nebula, almost perfectly spherical and also one of the largest known spheres with a radius of about 2.5 light-years:
Spherical Planetary Nebula Abell 39
Ghostly in appearance, Abell 39 is a remarkably simple, spherical nebula about five light-years across. Well within our own Milky Way galaxy, the cosmic sphere is roughly 7,000 light-years distant toward the constellation Hercules. Abell 39 is a planetary nebula, formed as a once sun-like star’s outer atmosphere was expelled over a period of thousands of years. Still visible, the nebula’s central star is evolving into a hot white dwarf. Although faint, the nebula's simple geometry has proven to be a boon to astronomers exploring the chemical abundances and life cycles of stars. In this deep image recorded under dark night skies, very distant background galaxies can be found- some visible right through the nebula itself.
[https://apod.nasa.gov/apod/ap121008.html]
NGC 6210 is a planetary nebula of the 9th magnitude, visible as a blue-green elliptical disk in amateur telescopes larger than 75 mm in aperture:
An odd planetary nebula in Hercules
The NASA/ESA Hubble Space Telescope has taken a striking high resolution image of the curious planetary nebula NGC 6210. Located about 6500 light-years away, in the constellation of Hercules, NGC 6210 was discovered in 1825 by the German astronomer Friedrich Georg Wilhelm Struve. Although in a small telescope it appears only as a tiny disc, it is fairly bright.
NGC 6210 is the last gasp of a star slightly less massive than our Sun at the final stage of its life cycle. The multiple shells of material ejected by the dying star form a superposition of structures with different degrees of symmetry, giving NGC 6210 its odd shape. This sharp image shows the inner region of this planetary nebula in unprecedented detail, where the central star is surrounded by a thin, bluish bubble that reveals a delicate filamentary structure. This bubble is superposed onto an asymmetric, reddish gas formation where holes, filaments and pillars are clearly visible.
The life of a star ends when the fuel available to its thermonuclear engine runs out. The estimated lifetime for a Sun-like star is some ten billion years. When the star is about to expire, it becomes unstable and ejects its outer layers, forming a planetary nebula and leaving behind a tiny, but very hot, remnant, known as white dwarf. This compact object, here visible at the center of the image, cools down and fades very slowly. Stellar evolution theory predicts that our Sun will experience the same fate as NGC 6210 in about five billion years.
This picture was created from images taken with Hubble’s Wide Field Planetary Camera 2 through three filters: the broadband filter F555W (yellow) and the narrowband filters F656N (ionized hydrogen), F658N (ionized nitrogen) and F502N (ionized oxygen). The exposure times were 80 s, 140 s, 800 s and 700 s respectively and the field of view is only about 28 arcseconds across.
[https://www.spacetelescope.org/images/potw1026a/]
Hercules A is a bright astronomical radio source within the vicinity of the constellation Hercules corresponding to the galaxy 3C 348:
[https://en.wikipedia.org/wiki/Hercules_A]
A Multi-Wavelength View of Radio Galaxy Hercules A
Spectacular jets powered by the gravitational energy of a super massive black hole in the core of the elliptical galaxy Hercules A illustrate the combined imaging power of two of astronomy’s cutting-edge tools, the Hubble Space Telescope’s Wide Field Camera 3, and the recently upgraded Karl G. Jansky Very Large Array (VLA) radio telescope in New Mexico.
Some two billion light-years away, the yellowish elliptical galaxy in the center of the image appears quite ordinary as seen by Hubble in visible wavelengths of light. The galaxy is roughly 1,000 times more massive than the Milky Way and harbors a 2.5-billion-solar-mass central black hole that is 1,000 times more massive than the black hole in the Milky Way. But the innocuous-looking galaxy, also known as 3C 348, has long been known as the brightest radio-emitting object in the constellation Hercules. Emitting nearly a billion times more power in radio wavelengths than our Sun, the galaxy is one of the brightest extragalactic radio sources in the entire sky.
[https://www.nasa.gov/mission_pages/hubble/science/hercules-a.html]
Zwicky 8338 is a concentration of galaxies located in the constellation Hercules:
[https://it.wikipedia.org/wiki/Zwicky_8338]
Zwicky 8338: Chandra Finds Remarkable Galactic Ribbon Unfurled
A gigantic tail of X-ray emission has been found behind a galaxy plowing through the galaxy cluster Zwicky 8338. With a length of at least 250,000 light years, this is likely the largest such tail ever detected. Scientists used Chandra to discover the tail, study its properties and learn how this X-ray tail affects its cluster environment.
An extraordinary ribbon of hot gas trailing behind a galaxy like a tail has been discovered using data from NASA’s Chandra X-ray Observatory, as described in our latest press release. This ribbon, or X-ray tail, is likely due to gas stripped from the galaxy as it moves through a vast cloud of hot intergalactic gas. With a length of at least 250,000 light years, it is likely the largest such tail ever detected. In this new composite image, X-rays from Chandra (blue) have been combined with data in visible light from the Isaac Newton Group of Telescopes (yellow) in the Canary Islands, Spain.
The tail is located in the galaxy cluster Zwicky 8338, which is almost 700 million light years from Earth. The length of the tail is more than twice the diameter of the entire Milky Way galaxy. The tail contains gas at temperatures of about ten million degrees, about twenty million degrees cooler than the intergalactic gas, but still hot enough to glow brightly in X-rays that Chandra can detect.
The researchers think the tail was created as a galaxy known as CGCG254-021, or perhaps a group of galaxies dominated by this large galaxy, plowed through the hot gas in Zwicky 8338. The pressure exerted by this rapid motion caused gas to be stripped away from the galaxy.
In images from Chandra and the NSF’s Karl Jansky Very Large Array (not shown in composite), the galaxy CGCG254-021 appears to be moving towards the bottom of the image with the tail following behind. There is a significant gap between the X-ray tail and the galaxy, the largest ever seen. The significant separation between the galaxy and the tail might be evidence that the gas has been completely stripped off the galaxy.
Astronomers were also able to learn more about the interactions of the system by carefully examining the properties of the galaxy and its tail. The tail has a brighter spot, referred to as its ‘head.’ Behind this head is the tail of diffuse X-ray emission. The gas in the head may be cooler and richer in elements heavier than helium than the rest of the tail. In front of the head there are hints of a bow shock, similar to a shock wave formed by a supersonic plane and in front of the bow shock is the galaxy CGCG254-021.
Independent research involving observations at infrared wavelengths indicates that CGCG254-021 has the highest mass of all galaxies in Zwicky 8338. The infrared observations, together with models for how galaxies evolve, also imply that among the galaxies in the cluster, CGCG254-021 had by far the highest rate of stars forming in the recent past. However, there is no evidence for new star formation, possibly because gas has been depleted in forming the tail.
Distance Estimate: About 680 million light years
[http://chandra.harvard.edu/photo/2015/z8338/index.html]
Arp 272 is a pair of interacting galaxies consisting of two spiral galaxies, which are part of the Hercules Cluster. The two galaxies in Arp 272 are in physical contact through their spiral arms. A third galaxy can be seen at the top of them; that galaxy is also interacting with them:
[https://en.wikipedia.org/wiki/Arp_272]
Arp 272
Linking spiral arms, two large colliding galaxies are featured in this remarkable cosmic portrait constructed using image data from the Hubble Legacy Archive. Recorded in astronomer Halton Arp’s Atlas of Peculiar Galaxies as Arp 272, the pair is otherwise known as NGC 6050 near center, and IC 1179 at upper right. A third galaxy, likely also a member of the interacting system, can be spotted above and left of larger spiral NGC 6050. They lie some 450 million light-years away in the Hercules Galaxy Cluster. At that estimated distance, the picture spans over 150 thousand light-years. Although this scenario does look peculiar, galaxy collisions and their eventual mergers are now understood to be common, with Arp 272 representing a stage in this inevitable process. In fact, the nearby large spiral Andromeda Galaxy is known to be approaching our own galaxy and Arp 272 may offer a glimpse of the far future collision between Andromeda and the Milky Way.
[https://apod.nasa.gov/apod/ap110922.html]
The Hercules Cluster (Abell 2151) is a cluster of about 200 galaxies some 500 million light-years distant in the constellation Hercules. It is rich in spiral galaxies and shows many interacting galaxies. The cluster is part of the larger Hercules Supercluster, which is itself part of the much larger Great Wall super-structure:
The Hercules Cluster of Galaxies
These are galaxies of the Hercules Cluster, an archipelago of island universes a mere 500 million light-years away. Also known as Abell 2151, this cluster is loaded with gas and dust rich, star-forming spiral galaxies but has relatively few elliptical galaxies, which lack gas and dust and the associated newborn stars. The colors in this remarkably deep composite image clearly show the star forming galaxies with a blue tint and galaxies with older stellar populations with a yellowish cast. The sharp picture spans about 3/4 degree across the cluster center, corresponding to over 6 million light-years at the cluster’s estimated distance. Diffraction spikes around brighter foreground stars in our own Milky Way galaxy are produced by the imaging telescope’s mirror support vanes. In the cosmic vista many galaxies seem to be colliding or merging while others seem distorted- clear evidence that cluster galaxies commonly interact. In fact, the Hercules Cluster itself may be seen as the result of ongoing mergers of smaller galaxy clusters and is thought to be similar to young galaxy clusters in the much more distant, early Universe.
[https://apod.nasa.gov/apod/ap140625.html]
The Hercules- Corona Borealis Great Wall, the largest structure in the universe, is in Hercules:
A giant Hubble mosaic of the massive galaxy cluster MACS J0717.5+3745 using a combination of 18 images. The significant amount of dark matter in this cluster, shown in light blue, may be also similar to the Hercules-Corona Borealis Great Wall.
The Hercules- Corona Borealis Great Wall or the Great GRB Wall is a massive galactic superstructure in a region of the sky seen in the data set mapping of gamma-ray bursts (GRBs) that has been found to have an unusually higher concentration of similarly distanced GRBs than the expected average distribution. It was discovered in early November 2013 by a team of American and Hungarian astronomers led by Istvan Horvath, Jon Hakkila and Zsolt Bagoly while analyzing data from the Swift Gamma-Ray Burst Mission, together with other data from ground-based telescopes.
The overdensity lies at the Second, Third and Fourth Galactic Quadrants (NQ2, NQ3 and NQ4) of the sky. Thus, it lies in the Northern Hemisphere, centered on the border of the constellations Draco and Hercules. The clustering crosses over 20 constellations and covers 125 degrees of the sky, or almost 15,000 square degrees in total area, which translates to about 18 to 23 billion light-years (5.5 to 7 billion parsecs) in length, and contains many billions of galaxies, depending on how they are counted.
Although large superclusters are known in the universe such as our own 520 million-light-year Laniakea Supercluster, a supercluster would have to be exceptionally immense to explain the clustering perhaps 30 to 50 times larger and 200 times the volume of expected typical superclusters. The current most plausible explanation for the existence of the Hercules–Corona Borealis Great Wall clustering is a supercluster within the region that shows a high rate of star formation. Since GRBs are linked with massive stars, such stars form only in regions with more matter.
[https://en.wikipedia.org/wiki/Hercules%E2%80%93Corona_Borealis_Great_Wall]
[https://en.wikipedia.org/wiki/Hercules_%28constellation%29]
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