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33-489: The Whirlpool Galaxy , also known as Messier 51a ( M51a ) or NGC 5194 , is an interacting grand-design spiral galaxy with a Seyfert 2 active galactic nucleus . It lies in the constellation Canes Venatici , and was the first galaxy to be classified as a spiral galaxy. It is 7.22 megaparsecs (23.5 million light-years) away and 23.58 kiloparsecs (76,900 ly) in diameter. The galaxy and its companion, NGC 5195 , are easily observed by amateur astronomers , and

66-414: A 100 mm telescope the basic outlines of M51 (limited to 5×6') and its companion are visible. Under dark skies, and with a moderate eyepiece through a 150 mm telescope, M51's intrinsic spiral structure can be detected. With larger (>300 mm) instruments under dark sky conditions, the various spiral bands are apparent with HII regions visible, and M51 can be seen to be attached to M51B . As

99-553: A 72-inch (1.8 m) reflecting telescope at Birr Castle , Ireland, found that the Whirlpool possessed a spiral structure , the first "nebula" to be known to have one. These " spiral nebulae " were not recognized as galaxies until Edwin Hubble was able to observe Cepheid variables in some of these spiral nebulae, which provided evidence that they were so far away that they must be entirely separate galaxies. The Whirlpool Galaxy

132-522: A constant angle significantly. The pronounced spiral structure of the Whirlpool Galaxy is believed to be the result of the close interaction between it and its companion galaxy NGC 5195 , which may have passed through the main disk of M51 about 500 to 600 million years ago. In this proposed scenario, NGC 5195 came from behind M51 through the disk towards the observer and made another disk crossing as recently as 50 to 100 million years ago until it

165-411: A distance of some tens of astronomical units . NGC 5195 (also known as Messier 51b or M51b) is a dwarf galaxy that is interacting with the Whirlpool Galaxy (also known as M51a or NGC 5194). Both galaxies are located approximately 25 million light-years away in the constellation Canes Venatici. Together, the two galaxies are one of the most widely studied interacting galaxy pairs. The Whirlpool Galaxy

198-649: A high altitude throughout this hemisphere making it an accessible object from the early hours in November through to the end of May, after which observation is more coincidental in modest latitudes with the risen sun (due to the Sun approaching to and receding from its right ascension , specifically figuring in Gemini , just to the north). M51 is visible through binoculars under dark sky conditions, and it can be resolved in detail with modern amateur telescopes. When seen through

231-607: A slightly bluer color, referred to as the Western plumes due to their location. In 2015, a study discovered two new tidal features caused by the interaction between the Whirlpool Galaxy and NGC 5195, the "Northeast plume" and the "South plume". The study remarks that a simulation that takes into account only one passage of NGC 5195 into the Whirpool Galaxy will fail to produce an analogue to the Northeast tail. In contrast,

264-535: Is about 88% the size of the Milky Way . Its mass is estimated to be 160 billion solar masses, or around 10.3% of the mass of Milky Way Galaxy. A black hole , once thought to be surrounded by a ring of dust, but now believed to be partially occluded by dust instead, exists at the heart of the spiral. A pair of ionization cones extend from the active galactic nucleus. The Whirlpool Galaxy has two, very prominent spiral arms that wind clockwise. One arm deviates from

297-650: Is common. A satellite's gravity could attract one of the primary's spiral arms . Alternatively, the secondary satellite can dive into the primary galaxy, as in the Sagittarius Dwarf Elliptical Galaxy diving into the Milky Way . That can possibly trigger a small amount of star formation . Such orphaned clusters of stars were sometimes referred to as "blue blobs" before they were recognized as stars. Colliding galaxies are common during galaxy evolution . The extremely tenuous distribution of matter in galaxies means these are not collisions in

330-709: Is the brightest galaxy in the M51 Group , a small group of galaxies that also includes M63 (the Sunflower Galaxy ), NGC 5023 , and NGC 5229 . This small group may actually be a subclump at the southeast end of a large, elongated group that includes the M101 Group and the NGC 5866 Group , although most group identification methods and catalogs identify the three groups as separate entities. Interacting galaxy A giant galaxy interacting with its satellites

363-550: Is usual for galaxies, the true extent of its structure can only be gathered from inspecting photographs; long exposures reveal a large nebula extending beyond the visible circular appearance. In 1984, thanks to the high-speed detector—the so-called image-photon-counting-system (IPCS)—developed jointly by the CNRS Laboratoire d'Astronomie Spatiald (L.A.S.-CNRS) and the Observatoire de Haute Provence (O.H.P.) along with

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396-477: Is where we observe it to be now, slightly behind M51. As a result of the Whirpool Galaxy's interaction with NGC 5195, a variety of tidal features have been created. The largest of these features is the so-called Northwest plume, which extends out to 43 kiloparsecs (140,000 light-years ) from the galaxy's center. This plume is uniform in color and likely originated from the Whirpool Galaxy itself due to having diffuse gas. Adjacent to it are two other plumes that have

429-582: The high-mass X-ray binary M51-ULS-1 in this galaxy was announced. If confirmed, it would be the first known instance of an extragalactic planet , a planet outside the Milky Way Galaxy. The planet candidate was detected by eclipses of the X-ray source (XRS), which consists of a stellar remnant (either a neutron star or a black hole ) and a massive star, likely a B-type supergiant . The planet would be slightly smaller than Saturn and orbit at

462-614: The Hubble Space Telescope's public data archive and planned new observations with the goal of producing aesthetically impactful, full color images that preserved the scientific integrity of the data. The Project was recognized for its contribution to public inspiration. Achievements for the team include the Astronomical Society of the Pacific 2003 Klumpke-Roberts Award for "outstanding contributions to

495-474: The Milky Way is taken as evidence for the theory. Galaxy harassment is a type of interaction between a low-luminosity galaxy and a brighter one that takes place within rich galaxy clusters , such as Virgo and Coma , where galaxies are moving at high relative speeds and suffering frequent encounters with other systems of the cluster due to the high galactic density. According to computer simulations ,

528-561: The Virgo Cluster and finding structures, such as disks and spiral arms, which suggest they are former disc systems transformed by the above-mentioned interactions. The existence of similar structures in isolated early-type dwarf galaxies, such as LEDA 2108986 , has undermined this hypothesis. Astronomers have estimated the Milky Way Galaxy will collide with the Andromeda Galaxy in about 4.5 billion years. Some think

561-468: The colliding galaxies is much larger than the other, it will remain largely intact after the merger. The larger galaxy will look much the same, while the smaller galaxy will be stripped apart and become part of the larger galaxy. When galaxies pass through each other, unlike during mergers, they largely retain their material and shape after the pass. Galactic collisions are now frequently simulated on computers, which use realistic physics principles, including

594-471: The current high rate of star formation can last no more than another 100 million years or so. Similarly, the spiral arms are experiencing high levels of star formation, as well as the space along the arms. Three supernovae have been observed in the Whirlpool Galaxy: In 1994, SN 1994I was observed in the Whirlpool Galaxy. It was classified as type Ic , indicating that its progenitor star

627-533: The galaxy's spiral arms, and shows detail into some of the structures inside the arms. The Whirlpool Galaxy lies at a distance of 23 to 31 million light-years from Earth. Based on the 1991 measurement by the Third Reference Catalogue of Bright Galaxies using the D 25 isophote at the B-band, the Whirlpool Galaxy has a diameter of 23.58 kiloparsecs (76,900 light-years ). Overall the galaxy

660-429: The interactions convert the affected galaxy disks into disturbed barred spiral galaxies and produces starbursts followed by, if more encounters occur, loss of angular momentum and heating of their gas. The result would be the conversion of (late type) low-luminosity spiral galaxies into dwarf spheroidals and dwarf ellipticals . Evidence for the hypothesis had been claimed by studying early-type dwarf galaxies in

693-415: The multiple-passage simulations made by Salo and Laurikainen et.al reproduce the northeast plume. The central region of M51 appears to be undergoing a period of enhanced star formation. The present efficiency of star formation, defined as the ratio of mass of new stars to the mass of star-forming gas, is only ~1%, quite comparable to the global value for the Milky Way and other galaxies. It is estimated that

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726-463: The pair of galaxies, in which case the individual galaxies may be referred to as M51a (NGC 5194) and M51b (NGC 5195). Deep in the constellation Canes Venatici , M51 is often found by finding the easternmost star of the Big Dipper , Alkaid , and going 3.5° southwest. Its declination is, rounded, +47°, making it circumpolar (never setting) for observers above the 43rd parallel north ; it reaches

759-648: The particularly nice visibility offered by the Canada-France-Hawaii-Telescope (C.F.H.T.) 3.60m Cassegrain focus on the summit of Mauna Kea in Hawaii, Hua et al. detected the double component of the very nucleus of the Whirlpool Galaxy. In January 2005 the Hubble Heritage Project constructed a 11,477 × 7,965-pixel composite image (shown in the infobox above) of M51 using Hubble's ACS instrument . The image highlights

792-512: The position of the transient in archival Hubble images, indicating that the progenitor star was heavily obstructed by interstellar dust . 2019abn peaked at magnitude 17, reaching an intrinsic brightness of M r = − 14.9 {\displaystyle M_{r}=-14.9} . In September 2020, the detection by the Chandra X-ray Observatory of a candidate exoplanet , named M51-ULS-1b , orbiting

825-560: The process in which a large galaxy , through tidal gravitational interactions with a companion, merges with that companion. The most common result of the gravitational merger between two or more galaxies is a larger irregular galaxy , but elliptical galaxies may also result. It has been suggested that galactic cannibalism is currently occurring between the Milky Way and the Large and Small Magellanic Clouds . Streams of gravitationally-attracted hydrogen arcing from these dwarf galaxies to

858-647: The public understanding and appreciation of astronomy." In 2002, two Heritage images were selected in the Rochester Institute of Technology 's "Images From Science" traveling gallery exhibit. Several images have been selected by the US and UK postal systems. In 2000, a first-class US postage stamp showing the Ring Nebula was one of five Hubble images selected to be part of a commemorative series of stamps honoring astronomer Edwin P. Hubble . The website of

891-484: The simulation of gravitational forces, gas dissipation phenomena, star formation, and feedback. Dynamical friction slows the relative motion of galaxy pairs, which may possibly merge at some point, according to the initial relative energy of the orbits. A library of simulated galaxy collisions can be found at the Paris Observatory website GALMER. Galactic cannibalism is a common phenomenon. It refers to

924-446: The traditional sense of the word, but rather gravitational interactions. Colliding may lead to merging if two galaxies collide and do not have enough momentum to continue traveling after the collision. As with other galaxy collisions , the merging of two galaxies may create a starburst region of new stars. In that case, they fall back into each other and eventually merge into one galaxy after many passes through each other. If one of

957-748: The two spiral galaxies will eventually merge to become an elliptical galaxy or perhaps a large disc galaxy . Hubble Heritage Project The Hubble Heritage Project was founded in 1998 by Keith Noll, Howard Bond, Forrest Hamilton, Anne Kinney, and Zoltan Levay at the Space Telescope Science Institute . Until its end in 2016, the Hubble Heritage Project released, on an almost monthly basis, pictures of celestial objects like planets , stars , galaxies and galaxy clusters . The team of astronomers and image processing specialists selected images from

990-486: The two galaxies may be seen with binoculars . The Whirlpool Galaxy has been extensively observed by professional astronomers, who study it and its pair with NGC 5195 to understand galaxy structure (particularly structure associated with the spiral arms ) and galaxy interactions. Its pair with NGC 5195 is among the most famous and relatively close interacting systems, and thus is a favorite subject of galaxy interaction models. William Parsons, 3rd Earl of Rosse , employing

1023-461: Was discovered on October 13, 1773, by Charles Messier while searching for objects that might confuse comet hunters. It was later cataloged as M51 in Messier's list of astronomical objects. The advent of radio astronomy and subsequent radio images of M51 unequivocally demonstrated that the Whirlpool and its companion galaxy are indeed interacting. Sometimes the designation M51 is used to refer to

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1056-467: Was probably a yellow supergiant and not a red or blue supergiant , which are thought to be the most common supernova progenitors. On 22 January 2019, a supernova impostor , designated AT 2019abn , was discovered in Messier 51. The transient was later identified as a luminous red nova . The progenitor star was detected in archival Spitzer Space Telescope infrared images. No object could be seen at

1089-535: Was very massive and had already shed much of its mass, and its brightness peaked at apparent magnitude 12.91. In June 2005 the type II supernova SN 2005cs was observed in the Whirlpool Galaxy, peaking at apparent magnitude 14. On 31 May 2011 a type II supernova was detected in the Whirlpool Galaxy, peaking at magnitude 12.1. This supernova, designated SN 2011dh , showed a spectrum much bluer than average, with P Cygni profiles, which indicate rapidly expanding material, in its hydrogen-Balmer lines . The progenitor

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