Messier 63 or M63 , also known as NGC 5055 or the seldom-used Sunflower Galaxy , is a spiral galaxy in the northern constellation of Canes Venatici with approximately 400 billion stars. M63 was first discovered by the French astronomer Pierre Méchain , then later verified by his colleague Charles Messier on 14 June 1779. The galaxy became listed as object 63 in the Messier Catalogue . In the mid-19th century, Anglo-Irish astronomer Lord Rosse identified spiral structures within the galaxy, making this one of the first galaxies in which such structure was identified.
18-417: The shape or morphology of this galaxy has a classification of SAbc, indicating a spiral form with no central bar feature (SA) and moderate to loosely wound arms (bc). There is a general lack of large-scale continuous spiral structure in visible light, so it is considered a flocculent galaxy . However, when observed in the near infrared , a symmetric, two-arm structure is seen. Each arm wraps 150° around
36-483: A three-dimensional version of Hubble's tuning fork, with stage (spiralness) on the x -axis, family (barredness) on the y -axis, and variety (ringedness) on the z -axis. De Vaucouleurs also assigned numerical values to each class of galaxy in his scheme. Values of the numerical Hubble stage T run from −6 to +10, with negative numbers corresponding to early-type galaxies (ellipticals and lenticulars) and positive numbers to late types (spirals and irregulars). Thus, as
54-422: A more elaborate classification system for spiral galaxies, based on three morphological characteristics: The different elements of the classification scheme are combined — in the order in which they are listed — to give the complete classification of a galaxy. For example, a weakly barred spiral galaxy with loosely wound arms and a ring is denoted SAB(r)c. Visually, the de Vaucouleurs system can be represented as
72-772: A rough rule, lower values of T correspond to a larger fraction of the stellar mass contained in a spheroid/bulge relative to the disk. The approximate mapping between the spheroid-to-total stellar mass ratio (M B /M T ) and the Hubble stage is M B /M T =(10−T) /256 based on local galaxies. Elliptical galaxies are divided into three 'stages': compact ellipticals (cE), normal ellipticals (E) and late types (E ). Lenticulars are similarly subdivided into early (S ), intermediate (S ) and late (S ) types. Irregular galaxies can be of type magellanic irregulars ( T = 10) or 'compact' ( T = 11). The use of numerical stages allows for more quantitative studies of galaxy morphology. The Yerkes scheme
90-533: Is 29,300,000 light-years (8.99 megaparsecs). The radial velocity relative to the Local Group yields an estimate of 15,200,000 light-years (4.65 megaparsecs). Estimates based on the Tully–Fisher relation range over 16,000,000–34,000,000 light-years (5.0–10.3 megaparsecs). The tip of the red-giant branch technique gives a distance of 28,930,000 ± 950,000 light-years (8.87 ± 0.29 megaparsecs). M63
108-628: Is a galaxy that does not have a distinct regular shape, unlike a spiral or an elliptical galaxy . Irregular galaxies do not fall into any of the regular classes of the Hubble sequence , and they are often chaotic in appearance, with neither a nuclear bulge nor any trace of spiral arm structure. Collectively they are thought to make up about a quarter of all galaxies. Some irregular galaxies were once spiral or elliptical galaxies but were deformed by an uneven external gravitational force. Irregular galaxies may contain abundant amounts of gas and dust. This
126-597: Is a morphological classification scheme for galaxies invented by Edwin Hubble in 1926. It is often known colloquially as the “Hubble tuning-fork” because of the shape in which it is traditionally represented. Hubble's scheme divides galaxies into three broad classes based on their visual appearance (originally on photographic plates ): These broad classes can be extended to enable finer distinctions of appearance and to encompass other types of galaxies, such as irregular galaxies , which have no obvious regular structure (either disk-like or ellipsoidal). The Hubble sequence
144-482: Is a system used by astronomers to divide galaxies into groups based on their visual appearance. There are several schemes in use by which galaxies can be classified according to their morphologies, the most famous being the Hubble sequence , devised by Edwin Hubble and later expanded by Gérard de Vaucouleurs and Allan Sandage . However, galaxy classification and morphology are now largely done using computational methods and physical morphology. The Hubble sequence
162-459: Is not necessarily true for dwarf irregulars. Irregular galaxies are commonly small, about one tenth the mass of the Milky Way galaxy, though there are also unusual cases of large irregulars like UGC 6697 . Due to their small sizes, they are prone to environmental effects like colliding with large galaxies and intergalactic clouds. There are three major types of irregular galaxies: Some of
180-406: Is often represented in the form of a two-pronged fork, with the ellipticals on the left (with the degree of ellipticity increasing from left to right) and the barred and unbarred spirals forming the two parallel prongs of the fork on the right. Lenticular galaxies are placed between the ellipticals and the spirals, at the point where the two prongs meet the “handle”. To this day, the Hubble sequence
198-518: Is part of the M51 Group , a group of galaxies that also includes M51 (the 'Whirlpool Galaxy'). In 1971, a supernova with a magnitude of 11.8 appeared in one of the arms. It was discovered on 24 May and reached peak light around 26 May. The spectrum of this, SN 1971I , is consistent with a supernova of type I . However, the spectroscopic behavior appeared anomalous. Galaxy morphological classification Galaxy morphological classification
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#1732854902295216-468: Is the most commonly used system for classifying galaxies, both in professional astronomical research and in amateur astronomy . Nonetheless, in June 2019, citizen scientists through Galaxy Zoo reported that the usual Hubble classification , particularly concerning spiral galaxies , may not be supported, and may need updating. The de Vaucouleurs system for classifying galaxies is a widely used extension to
234-618: The Hubble sequence , first described by Gérard de Vaucouleurs in 1959. De Vaucouleurs argued that Hubble's two-dimensional classification of spiral galaxies —based on the tightness of the spiral arms and the presence or absence of a bar—did not adequately describe the full range of observed galaxy morphologies. In particular, he argued that rings and lenses are important structural components of spiral galaxies. The de Vaucouleurs system retains Hubble's basic division of galaxies into ellipticals , lenticulars , spirals and irregulars . To complement Hubble's scheme, de Vaucouleurs introduced
252-429: The bright optical disk. This gas shows a symmetrical form that is warped in a pronounced manner, starting at a radius of 33,000 light-years (10 kiloparsecs). The form suggests a dark matter halo that is offset with respect to the inner region. The reason for the warp is unclear, but the position angle points toward the smaller companion galaxy, UGC 8313. The distance to M63, based upon the luminosity-distance measurement
270-505: The galaxy and extends out to 13,000 light-years (4,000 parsecs ) from the nucleus. M63 is a weakly active galaxy with a LINER nucleus – short for 'low-ionization nuclear emission-line region'. This displays as an unresolved source at the galactic nucleus that is cloaked in a diffuse emission . The latter is extended along a position angle of 110° relative to the north celestial pole , and both soft X-rays and hydrogen ( H-alpha ) emission can be observed coming from along nearly
288-541: The irregular galaxies, especially of the Magellanic type , are small spiral galaxies that are being distorted by the gravity of a larger neighbor. The Magellanic Cloud galaxies were once classified as irregular galaxies. The Large Magellanic Cloud has since been re-classified as type SBm (barred Magellanic spiral ). The Small Magellanic Cloud remains classified as an irregular galaxy of type Im under current galaxy morphological classification , although it does contain
306-449: The same direction. The existence of a supermassive black hole (SMBH) at the nucleus is uncertain; if it does exist, then the mass is estimated as (8.5 ± 1.9) × 10 M ☉ , or around 850 million times the mass of the Sun. Radio observations at the 21-cm hydrogen line show the gaseous disk of M63 extends outward to a radius of 130,000 light-years (40 kiloparsecs), well past
324-557: Was created by American astronomer William Wilson Morgan . Together with Philip Keenan , Morgan also developed the MK system for the classification of stars through their spectra. The Yerkes scheme uses the spectra of stars in the galaxy; the shape, real and apparent; and the degree of the central concentration to classify galaxies. Thus, for example, the Andromeda Galaxy is classified as kS5. Irregular galaxy An irregular galaxy
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