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115-540: Comet Shoemaker–Levy 9 ( formally designated D/1993 F2 ) was a comet that broke apart in July 1992 and collided with Jupiter in July 1994, providing the first direct observation of an extraterrestrial collision of Solar System objects. This generated a large amount of coverage in the popular media, and the comet was closely observed by astronomers worldwide. The collision provided new information about Jupiter and highlighted its possible role in reducing space debris in

230-412: A dwarf planet . When the object is found around a minor planet, the identifier used is the latter's number in parentheses. Thus, Dactyl , the moon of 243 Ida , was at first designated " S/1993 (243) 1 ". Once confirmed and named, it became (243) Ida I Dactyl . Similarly, the fourth satellite of Pluto, Kerberos , discovered after Pluto was categorized as a dwarf planet and assigned a minor planet number,

345-409: A fireball that reached a peak temperature of about 24,000  K (23,700 °C; 42,700 °F), compared to the typical Jovian cloud-top temperature of about 130  K (−143 °C; −226 °F). It then expanded and cooled rapidly to about 1,500 K (1,230 °C; 2,240 °F). The plume from the fireball quickly reached a height of over 3,000 km (1,900 mi) and was observed by

460-405: A Greek-born astronomer working at Meudon , France. However, the age of space probes brought high-resolution images of various Solar System bodies, and it became necessary to propose naming standards for the features seen on them. Initially, the names given to minor planets followed the same pattern as the other planets: names from Greek or Roman myths, with a preference for female names. With

575-431: A Schmidt photographic plate taken on March 19 was identified on March 21 by M. Lindgren, in a project searching for comets near Jupiter. However, as his team were expecting comets to be inactive or at best exhibit a weak dust coma, and SL9 had a peculiar morphology, its true nature was not recognised until the official announcement 5 days later. No precovery images dating back to earlier than March 1993 have been found. Before

690-426: A capitalized A. Its companions are labelled B, C, and so on. For example, Sirius , the brightest star in the sky, is actually a double star, consisting of the naked-eye visible Sirius A and its dim white-dwarf companion Sirius B . The first exoplanet tentatively identified around the second brightest star in the triple star system Alpha Centauri is accordingly called Alpha Centauri Bb . If an exoplanet orbits both of

805-483: A few minutes after the collisions. Two other space probes made observations at the time of the impact: the Ulysses spacecraft , primarily designed for solar observations, was pointed toward Jupiter from its location 2.6 AU (390 million km; 240 million mi) away, and the distant Voyager 2 probe, some 44 AU (6.6 billion km; 4.1 billion mi) from Jupiter and on its way out of

920-465: A history of how some of the major satellites got their current names. The Roman numbering system arose with the very first discovery of natural satellites other than Earth's: Galileo referred to the Galilean moons as I through IV (counting from Jupiter outward), in part to spite his rival Simon Marius , who had proposed the names now adopted, after his own proposal to name the bodies after members of

1035-496: A letter of the alphabet, from "fragment A" through to "fragment W", a practice already established from previously observed fragmented comets. More exciting for planetary astronomers was that the best orbital calculations suggested that the comet would pass within 45,000 km (28,000 mi) of the center of Jupiter, a distance smaller than the planet's radius, meaning that there was an extremely high probability that SL9 would collide with Jupiter in July 1994. Studies suggested that

1150-634: A number and the Latin genitive of the constellation the star lies in. Examples include 51 Pegasi and 61 Cygni . About 2,500 stars are catalogued. They are commonly used when no Bayer designation exists, or when the Bayer designation uses numeric superscripts such as in Rho¹ ;Cancri . In this case, the simpler Flamsteed designation, 55 Cancri , is often preferred. Most modern catalogues are generated by computers, using high-resolution, high-sensitivity telescopes, and as

1265-477: A number of systematic naming systems for objects of various sorts. There are no more than a few thousand stars that appear sufficiently bright in Earth's sky to be visible to the naked eye . This represents the number of stars available to be named by ancient cultures. The upper boundary to what is physiologically possible to be seen with the unaided eye is an apparent magnitude of 6, or about ten thousand stars. With

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1380-579: A photograph taken with the 46 cm (1.51 ft) Schmidt telescope at the Palomar Observatory in California . The comet was thus a serendipitous discovery, but one that quickly overshadowed the results from their main observing program. Comet Shoemaker–Levy 9 was the ninth periodic comet (a comet whose orbital period is 200 years or less) discovered by the Shoemakers and Levy, thence its name . It

1495-594: A planet, and had probably been captured by Jupiter around 20 to 30 years earlier. Calculations showed that its unusual fragmented form was due to a previous closer approach to Jupiter in July 1992. At that time, the orbit of Shoemaker–Levy 9 passed within Jupiter's Roche limit , and Jupiter's tidal forces had acted to pull the comet apart. The comet was later observed as a series of fragments ranging up to 2 km (1.2 mi) in diameter. These fragments collided with Jupiter's southern hemisphere between July 16 and 22, 1994 at

1610-487: A result describe very large numbers of objects. For example, the Guide Star Catalog II has entries on over 998 million distinct astronomical objects. Objects in these catalogs are typically located with very high resolution, and assign designations to these objects based on their position in the sky. An example of such a designation is SDSSp J153259.96−003944.1 , where the initialism SDSSp indicates that

1725-708: A result of the NameExoWorlds campaign in December 2015 the IAU approved the names Cervantes (honoring the writer Miguel de Cervantes ) and Copernicus (honoring the astronomer Nicolaus Copernicus ) for the stars Mu Arae and 55 Cancri A , respectively. In July 2016, the IAU WGSN approved the name Cor Caroli ( Latin for 'heart of Charles') for the star Alpha Canum Venaticorum , so named in honour of King Charles I of England by Sir Charles Scarborough , his physician. In 2019, IAU held

1840-474: A sequential number is assigned by the Minor Planet Center to the minor-planet designation . After the designation is assigned, the discoverer is given an opportunity to propose a name, which, if accepted by the IAU, replaces the provisional designation. Thus for instance, (28978) 2001 KX 76 was given the name Ixion and is now called 28978 Ixion . The name becomes official after its publication in

1955-446: A set of generic rules for the data formats used. The IAU does not recognize the commercial practice of selling fictitious star names by commercial star-naming companies . There are about 300 to 350 stars with traditional or historical proper names. They tend to be the brightest stars in the sky and are often the most prominent ones of the constellation . Examples are Betelgeuse , Rigel and Vega . Most such names are derived from

2070-470: A small undiscovered asteroid, was the cause. The events of SL9's interaction with Jupiter greatly highlighted Jupiter's role in protecting the inner planets from both interstellar and in-system debris by acting as a "cosmic vacuum cleaner" for the Solar System ( Jupiter barrier ). The planet's strong gravitational influence attracts many small comets and asteroids and the rate of cometary impacts on Jupiter

2185-471: A speed of approximately 60 km/s (37 mi/s) (Jupiter's escape velocity ) or 216,000 km/h (134,000 mph). The prominent scars from the impacts were more visible than the Great Red Spot and persisted for many months. While conducting a program of observations designed to uncover near-Earth objects , the Shoemakers and Levy discovered Comet Shoemaker–Levy 9 on the night of March 24, 1993, in

2300-547: A trans-Plutonian planet. Derived from Classical mythology , these names are only considered standard in Western discussion of the planets. Astronomers in societies that have other traditional names for the planets may use those names in scientific discourse. For instance, IAU does not disapprove of astronomers discussing Jupiter in Arabic using the traditional Arabic name for the planet, المشتري Al-Mushtarīy . Some sixty years after

2415-524: A week of the impact. At smaller sites, temperatures 10 K (10 ° C; 18 ° F) higher than the surroundings persisted for almost two weeks. Global stratospheric temperatures rose immediately after the impacts, then fell to below pre-impact temperatures 2–3 weeks afterwards, before rising slowly to normal temperatures. SL9 is not unique in having orbited Jupiter for a time; five comets, including 82P/Gehrels , 147P/Kushida–Muramatsu , and 111P/Helin–Roman–Crockett , are known to have been temporarily captured by

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2530-623: Is especially prevalent in science fiction where the adjective "terran" is also used in the way which "Lunar" or "Jovian" is for Earth's moon or Jupiter. The Latin convention derives from the use of that language as an international scientific language by the first modern astronomers like Copernicus, Kepler, Galileo, Newton and others and was used for a long time. This is why the later discovered bodies were also named accordingly. Two more bodies that were discovered later, and considered planets when discovered, are still generally considered planets now: These were given names from Greek or Roman myth, to match

2645-494: Is followed by the pulsar's right ascension and degrees of declination . The right ascension is also prefixed with a "J" ( Julian epoch ) or a "B" ( Besselian Epochs ) used prior to 1993, as in PSR B1257+12 . Black holes have no consistent naming conventions. Supermassive black holes receive the designation of the galaxy whose core they reside in. Examples are NGC 4261 , NGC 4151 and M31 , which derive their designation from

2760-435: Is formed by the standard prefix "SN", the year of discovery, and a suffix composed of one to three letters of the Latin alphabet. The first 26 supernovae of the year receive a capital letter from A to Z . Subsequent supernovae of that year are designated with pairs of lower-case letters from "aa" to "az", and then continuing with "ba" until "zz". Then come "aaa", "aab", and so on (this first occurred in 2015-2016). For example,

2875-456: Is likely that it was captured from a solar orbit in the early 1970s, although the capture may have occurred as early as the mid-1960s. Several other observers found images of the comet in precovery images obtained before March 24, including Kin Endate from a photograph exposed on March 15, Satoru Otomo on March 17, and a team led by Eleanor Helin from images on March 19. An image of the comet on

2990-469: Is named after its first independent discoverers, up to a maximum of three names, separated by hyphens. The IAU prefers to credit at most two discoverers, and it credits more than three discoverers only when "in rare cases where named lost comets are identified with a rediscovery that has already received a new name." In recent years, many comets have been discovered by instruments operated by large teams of astronomers, and in this case, comets may be named for

3105-502: Is part of the argument used in the Rare Earth hypothesis . In 2009, it was shown that the presence of a smaller planet at Jupiter's position in the Solar System might increase the impact rate of comets on the Earth significantly. A planet of Jupiter's mass still seems to provide increased protection against asteroids, but the total effect on all orbital bodies within the Solar System is unclear. This and other recent models call into question

3220-715: Is thought to be between 2,000 and 8,000 times higher than the rate on Earth. The extinction of the non-avian dinosaurs at the end of the Cretaceous period is generally thought to have been caused by the Cretaceous–Paleogene impact event , which created the Chicxulub crater , demonstrating that cometary impacts are indeed a serious threat to life on Earth. Astronomers have speculated that without Jupiter's immense gravity, extinction events might have been more frequent on Earth and complex life might not have been able to develop. This

3335-448: Is to ensure that names assigned are unambiguous. There have been many historical star catalogues , and new star catalogues are set up on a regular basis as new sky surveys are performed. All designations of objects in recent star catalogues start with an "initialism", which is kept globally unique by the IAU. Different star catalogues then have different naming conventions for what goes after the initialism, but modern catalogs tend to follow

3450-459: Is typically referred to simply as "the Sun" or its equivalent in the language being used (for instance, if two astronomers were speaking French, they would call it le Soleil ). However, it is usually called by its Latin name, Sol, in science fiction. There are about two dozen stars such as Barnard's Star and Kapteyn's Star that have historic names and which were named in honor after astronomers . As

3565-422: Is used for planetary rings. These designations are sometimes written like "S/2003 S1", dropping the second space. The letter following the category and year identifies the planet ( J upiter, S aturn, U ranus, N eptune; although no occurrence of the other planets is expected, Mars and Mercury are disambiguated through the use of H ermes for the latter). Pluto was designated by P prior to its recategorization as

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3680-461: The Galileo spacecraft , then on its way to a rendezvous with Jupiter scheduled for 1995. Although the impacts took place on the side of Jupiter hidden from Earth, Galileo , then at a distance of 1.6 AU (240 million km; 150 million mi) from the planet, was able to see the impacts as they occurred. Jupiter's rapid rotation brought the impact sites into view for terrestrial observers

3795-561: The New General Catalogue and the list of Messier objects . Other black holes, such as Cygnus X-1 – a highly likely stellar black hole , are cataloged by their constellation and the order in which they were discovered. A large number of black holes are designated by their position in the sky and prefixed with the instrument or survey that discovered them. Examples are SDSS J0100+2802 (where SDSS stands for Sloan Digital Sky Survey ), and RX J1131−1231 , observed by

3910-628: The Arabic language (see List of Arabic star names § History of Arabic star names ) . Stars may have multiple proper names, as many different cultures named them independently. Polaris , for example, has also been known by the names Alruccabah , Angel Stern, Cynosura , the Lodestar , Mismar , Navigatoria , Phoenice , the Pole Star , the Star of Arcady , Tramontana and Yilduz at various times and places by different cultures in human history. In 2016,

4025-518: The Central Bureau for Astronomical Telegrams noted that the comet lay only about 4  degrees from Jupiter as seen from Earth, and that although this could be a line-of-sight effect, its apparent motion in the sky suggested that the comet was physically close to the planet. Orbital studies of the new comet soon revealed that it was orbiting Jupiter rather than the Sun , unlike all other comets known at

4140-500: The Chandra X-ray Observatory . Supernova discoveries are reported to the IAU's Central Bureau for Astronomical Telegrams and are automatically given a provisional designation based on the co-ordinates of the discovery. Historically, when supernovae are identified as belonging to a "type", CBAT has also published circulars with assigned year–letter designations, and discovery details. A supernova's permanent designation

4255-524: The Great Red Spot . A search of historical observations revealed that the spots were probably the most prominent transient features ever seen on the planet, and that although the Great Red Spot is notable for its striking color, no spots of the size and darkness of those caused by the SL9 impacts had ever been recorded before, or since. Spectroscopic observers found that ammonia and carbon disulfide persisted in

4370-459: The IAU President and General Secretary. Minor planets observed over at least two nights and which cannot be identified with an existing celestial object, are initially assigned provisional designations (containing the year and the sequential order of discovery within that year) by the Minor Planet Center. When enough observations of the same object are obtained to calculate a reliable orbit,

4485-617: The IAU organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN (on 30 June and 20 July 2016) together with names of stars adopted by the IAU Executive Committee Working Group on Public Naming of Planets and Planetary Satellites during the 2015 NameExoWorlds campaign and recognized by

4600-445: The Io torus , a torus of high-energy particles connecting Jupiter with the highly volcanic moon Io . High resolution spectroscopic studies found that variations in the ion density , rotational velocity , and temperatures at the time of impact and afterwards were within the normal limits. Voyager 2 failed to detect anything with calculations, showing that the fireballs were just below

4715-453: The Medici family failed to win currency. Similar numbering schemes naturally arose with the discovery of moons around Saturn and Mars. Although the numbers initially designated the moons in orbital sequence, new discoveries soon failed to conform with this scheme (e.g. "Jupiter V" is Amalthea , which orbits closer to Jupiter than does Io ). The unstated convention then became, at the close of

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4830-523: The Messier catalog has 110 in total. The Andromeda Galaxy is Messier object 31, or M31 ; the Whirlpool Galaxy is M51 . The New General Catalogue (NGC, J. L. E. Dreyer 1888) was much larger and contained nearly 8,000 objects, still mixing galaxies with nebulas and star clusters. The brightest planets in the sky have been named from ancient times. The scientific names are taken from the names given by

4945-466: The NameExoWorlds campaign. With the advent of the increased light-gathering abilities of the telescope, many more stars became visible, far too many to all be given names. Instead, they have designations assigned to them by a variety of different star catalogues . Older catalogues either assigned an arbitrary number to each object, or used a simple systematic naming scheme based on the constellation

5060-475: The WGSBN Bulletin with a brief citation explaining its significance. This may be a few years after the initial sighting, or in the case of "lost" asteroids , it may take several decades before they are spotted again and finally assigned a designation. If a minor planet remains unnamed ten years after it has been given a designation, the right to name it is given also to identifiers of the various apparitions of

5175-547: The celestial sphere belongs to a particular constellation. Like stars, most galaxies do not have names. There are a few exceptions such as the Andromeda Galaxy , the Whirlpool Galaxy , and others, but most simply have a catalog number. In the 19th century, the exact nature of galaxies was not yet understood, and the early catalogs simply grouped together open clusters , globular clusters , nebulas , and galaxies:

5290-438: The inner Solar System . The comet was discovered by astronomers Carolyn and Eugene M. Shoemaker , and David Levy in 1993. Shoemaker–Levy 9 (SL9) had been captured by Jupiter and was orbiting the planet at the time. It was located on the night of March 24 in a photograph taken with the 46 cm (18 in) Schmidt telescope at the Palomar Observatory in California . It was the first active comet observed to be orbiting

5405-466: The 19th century, that the numbers more or less reflected the order of discovery, except for prior historical exceptions (see the Timeline of discovery of Solar System planets and their moons ). In addition to naming planets and satellites themselves, the individual geological and geographical features such as craters, mountains, and volcanoes, on those planets and satellites also need to be named. In

5520-459: The HST. A few minutes after the impact fireball was detected, Galileo measured renewed heating, probably due to ejected material falling back onto the planet. Earth-based observers detected the fireball rising over the limb of the planet shortly after the initial impact. Despite published predictions, astronomers had not expected to see the fireballs from the impacts and did not have any idea how visible

5635-557: The Romans: Mercury , Venus , Mars , Jupiter , and Saturn . Our own planet is usually named in English as Earth , or the equivalent in the language being spoken (for instance, two astronomers speaking French would call it la Terre ). However, it is only recently in human history that it has been thought of as a planet. Earth, when viewed as a planet, is sometimes also called by its Latin scientific conventional name Terra , this name

5750-495: The SL9 impacts, a new black spot about the size of the Pacific Ocean appeared in Jupiter's southern hemisphere. Thermal infrared measurements showed the impact site was warm and spectroscopic analysis detected the production of excess hot ammonia and silica-rich dust in the upper regions of Jupiter's atmosphere. Scientists have concluded that another impact event had occurred, but this time a more compact and stronger object, probably

5865-480: The Solar System following its encounter with Neptune in 1989, was programmed to look for radio emission in the 1–390  kHz range and make observations with its ultraviolet spectrometer. Astronomer Ian Morison described the impacts as following: The first impact occurred at 20:13  UTC on July 16, 1994, when fragment A of the [comet's] nucleus slammed into Jupiter's southern hemisphere at about 60 km/s (35 mi/s). Instruments on Galileo detected

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5980-689: The Southern Cross, Epsilon Carinae ( ε Car ) in Carina, Lambda Scorpii ( λ Sco ) in Scorpius and Sigma Sagittarii ( σ Sgr ) in Sagittarius. After all twenty-four Greek letters have been assigned, upper and lower case Latin letters are used, such as for A Centauri ( A Cen ), D Centauri ( D Cen ), G Scorpii ( G Sco ), P Cygni ( P Cyg ), b Sagittarii ( b Sgr ), d Centauri ( d Cen ) and s Carinae ( s Car ). As

6095-507: The WGSBN has officially limited naming to a maximum of two names per discoverer every two months. Thus, the overwhelming majority of asteroids currently discovered are not assigned formal names. Under IAU rules, names must be pronounceable, preferably one word (such as 5535 Annefrank ), although exceptions are possible (such as 9007 James Bond ), and since 1982, names are limited to a maximum of 16 characters, including spaces and hyphens. (This rule

6210-449: The WGSN. Further batches of names were approved on 21 August 2016, 12 September 2016 and 5 October 2016. These were listed in a table included in the WGSN's second bulletin issued in October 2016. The next additions were done on 1 February, 30 June, 5 September and 19 November 2017, and on 6 June 2018. All are included on the current List of IAU-approved Star Names. The star nearest to Earth

6325-507: The advent of the increased light-gathering abilities of the telescope, many more stars became visible, far too many to all be given names. The earliest naming system which is still popular is the Bayer designation using the name of constellations to identify the stars within them. The IAU is the only internationally recognized authority for assigning astronomical designations to celestial objects and surface features on them. The purpose of this

6440-771: The ancient planet names—but only after some controversy. For example, Sir William Herschel discovered Uranus in 1781, and originally called it Georgium Sidus (George's Star) in honour of King George III of the United Kingdom . French astronomers began calling it Herschel before German Johann Bode proposed the name Uranus, after the Greek god. The name "Uranus" did not come into common usage until around 1850. Starting in 1801, asteroids were discovered between Mars and Jupiter. The first few ( Ceres , Pallas , Juno , Vesta ) were initially considered planets. As more and more were discovered, they were soon stripped of their planetary status. On

6555-505: The atmosphere for at least fourteen months after the collisions, with a considerable amount of ammonia being present in the stratosphere as opposed to its normal location in the troposphere. Counterintuitively, the atmospheric temperature dropped to normal levels much more quickly at the larger impact sites than at the smaller sites: at the larger impact sites, temperatures were elevated over a region 15,000 to 20,000 km (9,300 to 12,400 mi) wide, but dropped back to normal levels within

6670-472: The chaotic lunar and Martian nomenclatures then current. Much of the work was done by Mary Adela Blagg , and the report Named Lunar Formations by Blagg and Muller (1935), was the first systematic listing of lunar nomenclature. Later, "The System of Lunar Craters, quadrants I, II, III, IV" was published, under the direction of Gerard P. Kuiper . These works were adopted by the IAU and became the recognized sources for lunar nomenclature. The Martian nomenclature

6785-491: The comet towards it. Because the comet's motion with respect to Jupiter was very small, it fell almost straight toward Jupiter, which is why it ended up on a Jove-centric orbit of very high eccentricity—that is to say, the ellipse was nearly flattened out. The comet had apparently passed extremely close to Jupiter on July 7, 1992, just over 40,000 km (25,000 mi) above its cloud tops—a smaller distance than Jupiter's radius of 70,000 km (43,000 mi), and well within

6900-466: The comet was captured by Jupiter, it was probably a short-period comet with an aphelion just inside Jupiter's orbit, and a perihelion interior to the asteroid belt . The volume of space within which an object can be said to orbit Jupiter is defined by Jupiter's Hill sphere . When the comet passed Jupiter in the late 1960s or early 1970s, it happened to be near its aphelion, and found itself slightly within Jupiter's Hill sphere. Jupiter's gravity nudged

7015-486: The cometary fragments did not penetrate deeply enough. As predicted, the collisions generated enormous waves that swept across Jupiter at speeds of 450 m/s (1,500 ft/s) and were observed for over two hours after the largest impacts. The waves were thought to be travelling within a stable layer acting as a waveguide , and some scientists thought the stable layer must lie within the hypothesised tropospheric water cloud. However, other evidence seemed to indicate that

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7130-464: The cometary fragments had not reached the water layer, and the waves were instead propagating within the stratosphere . Radio observations revealed a sharp increase in continuum emission at a wavelength of 21 cm (8.3 in) after the largest impacts, which peaked at 120% of the normal emission from the planet. This was thought to be due to synchrotron radiation , caused by the injection of relativistic electrons —electrons with velocities near

7245-522: The cometary fragments in a meteor air burst probably occurred at much higher altitudes than previously expected, with even the largest fragments being destroyed when the pressure reached 250 kPa (36 psi), well above the expected depth of the water layer. The smaller fragments were probably destroyed before they even reached the cloud layer. The visible scars from the impacts could be seen on Jupiter for many months. They were extremely prominent, and observers described them as more easily visible than

7360-401: The constellation's name is plural (see genitive case for constellations ) . In addition, a three-letter abbreviation is often used . Examples include Alpha Andromedae ( α And ) in the constellation of Andromeda, Alpha Centauri ( α Cen ), in the constellation Centaurus, Alpha Crucis ( α Cru ) and Beta Crucis ( β Cru ), the two brightest stars in the constellation Crux,

7475-419: The craft's limit of detection; no abnormal levels of UV radiation or radio signals were registered after the blast. Ulysses also failed to detect any abnormal radio frequencies. Several models were devised to compute the density and size of Shoemaker–Levy 9. Its average density was calculated to be about 0.5 g/cm (0.018 lb/cu in); the breakup of a much less dense comet would not have resembled

7590-456: The designation is from the " Sloan Digital Sky Survey preliminary objects", and the other characters indicate celestial coordinates ( epoch 'J', right ascension 15 32 59.96 , declination −00°39′44.1″). Variable stars are assigned designations in a variable star scheme that is based on a variation of the Bayer designation format, with an identifying label preceding the Latin genitive of

7705-404: The designations usually consists of a proper noun or abbreviation that often corresponds to the star's name, followed by a lowercase letter (starting with 'b'), like 51 Pegasi b . The lowercase lettering style is drawn from the IAU's long-established rules for naming binary and multiple star systems. A primary star, which is brighter and typically bigger than its companion stars, is designated by

7820-404: The discovery in 1898 of the first body found to cross the orbit of Mars, a different choice was deemed appropriate, and 433 Eros was chosen. This started a pattern of female names for main-belt bodies and male names for those with unusual orbits. As more and more discoveries were made over the years, this system was eventually recognized as being inadequate and a new one was devised. Currently,

7935-448: The discovery of Pluto, a large number of large trans-Neptunian objects began to be discovered. Under the criteria of classifying these Kuiper belt objects (KBOs), it became dubious whether Pluto would have been considered a planet had it been discovered in the 1990s. Its mass is now known to be much smaller than once thought and, with the discovery of Eris , it is simply one of the two largest known trans-Neptunian objects. In 2006, Pluto

8050-437: The early 21st century, hundreds of supernovae were reported every year to the IAU, with more than 500 catalogued in 2007. Since then, the number of newly discovered supernovae has increased to thousands per year, for example almost 16,000 supernovae observations were reported in 2019, more than 2,000 of which were named by CBAT. The sky was divided into constellations by historic astronomers, according to perceived patterns in

8165-469: The early days, only a very limited number of features could be seen on other Solar System bodies other than the Moon . Craters on the Moon could be observed with even some of the earliest telescopes, and 19th-century telescopes could make out some features on Mars. Jupiter had its famous Great Red Spot , also visible through early telescopes. In 1919, the IAU was formed, and it appointed a committee to regularize

8280-442: The first known precovery images of Comet Shoemaker-Levy 9 with his private 10-inch (25 cm) diameter telescope on March 15, 1993, ten days before the official discovery of the comet. Kin, who was looking specifically for asteroids, did not know of the comet in his images until after the official discovery. The main-belt asteroid 4282 Endate , discovered by his colleagues Seiji Ueda and Hiroshi Kaneda at Kushiro in 1987,

8395-402: The geometry of the impact sites. One possible explanation was that upwardly accelerating shock waves from the impact accelerated charged particles enough to cause auroral emission, a phenomenon more typically associated with fast-moving solar wind particles striking a planetary atmosphere near a magnetic pole . Some astronomers had suggested that the impacts might have a noticeable effect on

8510-569: The hyphen was replaced by a space. The spaces, apostrophes and other characters in discoverer names are preserved in comet names, like 32P/Comas Solà , 6P/d'Arrest , 53P/Van Biesbroeck , Comet van den Bergh (1974g) , 66P/du Toit , or 57P/du Toit–Neujmin–Delporte . Kin Endate Kin Endate ( 円館 金 , Endate Kin , born December 15, 1960) is a Japanese amateur astronomer who has discovered hundreds of asteroids, most of them in collaboration with Kazuro Watanabe , placing him among

8625-472: The instrument (for example, Comet IRAS–Araki–Alcock (C/1983 H1) was discovered independently by the IRAS satellite and amateur astronomers Genichi Araki and George Alcock ). Comet 105P/Singer Brewster , discovered by Stephen Singer-Brewster , should by rights have been named "105P/Singer-Brewster", but this could be misinterpreted as a joint discovery by two astronomers named Singer and Brewster, respectively, so

8740-490: The largest coming on July 18 at 07:33 UTC when fragment G struck Jupiter. This impact created a giant dark spot over 12,000 km or 7,500 mi (almost one Earth diameter ) across, and was estimated to have released an energy equivalent to 6,000,000  megatons of TNT (600 times the world's nuclear arsenal). Two impacts 12 hours apart on July 19 created impact marks of similar size to that caused by fragment G, and impacts continued until July 22, when fragment W struck

8855-432: The largest fragments would occur at atmospheric pressures of anywhere from 30 kilopascals to a few tens of megapascals (from 0.3 to a few hundred bar ), with some predictions that the comet would penetrate a layer of water and create a bluish shroud over that region of Jupiter. Astronomers did not observe large amounts of water following the collisions, and later impact studies found that fragmentation and destruction of

8970-597: The most prolific discoverers of minor planets . Kin Endate was born in Iwaizumi in Iwate Prefecture and went to Hokkaido Designers School to study photography. He began taking astrophotos in high school, but did not begin serious asteroid observations until 1986. His notable discoveries include the minor planets 5648 Axius and 6500 Kodaira , a Jupiter trojan and the Mars-crosser , respectively. He also recorded

9085-533: The name of the constellation in which the star lies. Such designations mark them as variable stars. Examples include R Cygni , RR Lyrae , and V1331 Cygni . The International Astronomical Union delegates the task to the Sternberg Astronomical Institute in Moscow, Russia. Pulsars such as PSR J0737-3039 , are designated with a "PSR" prefix, that stands for Pulsating Source of Radio . The prefix

9200-413: The nature of Jupiter's influence on Earth impacts. Astronomical naming conventions#Comets The International Astronomical Union (IAU) is the recognized authority in astronomy for assigning designations to celestial bodies such as stars, planets, and minor planets , including any surface features on them. In response to the need for unambiguous names for astronomical objects, it has created

9315-525: The object, to discoverers at apparitions other than the official one, to those whose observations contributed extensively to the orbit determination, or to representatives of the observatory at which the official discovery was made. The WGSBN has the right to act on its own in naming a minor planet, which often happens when the number assigned to the body is an integral number of thousands. In recent years, automated search efforts such as LINEAR or LONEOS have discovered so many thousands of new asteroids that

9430-412: The observed string of objects. The size of the parent comet was calculated to be about 1.8 km (1.1 mi) in diameter. These predictions were among the few that were actually confirmed by subsequent observation. One of the surprises of the impacts was the small amount of water revealed compared to prior predictions. Before the impact, models of Jupiter's atmosphere had indicated that the break-up of

9545-403: The orbit of Jupiter's innermost moon Metis and the planet's Roche limit , inside which tidal forces are strong enough to disrupt a body held together only by gravity. Although the comet had approached Jupiter closely before, the July 7 encounter seemed to be by far the closest, and the fragmentation of the comet is thought to have occurred at this time. Each fragment of the comet was denoted by

9660-421: The original comet may have had a nucleus up to 5 km (3.1 mi) across—somewhat larger than Comet Hyakutake , which became very bright when it passed close to the Earth in 1996. One of the great debates in advance of the impact was whether the effects of the impact of such small bodies would be noticeable from Earth, apart from a flash as they disintegrated like giant meteors . The most optimistic prediction

9775-454: The original discoverer of the comet, Pierre Méchain. Other comets that bore the possessive include "Biela's Comet" ( 3D/Biela ) and "Miss Herschel's Comet" ( 35P/Herschel–Rigollet , or Comet Herschel–Rigollet). Most bright (non-periodic) comets were referred to as 'The Great Comet Of...' the year in which they appeared. In the early 20th century, the convention of naming comets after their discoverers became common, and this remains today. A comet

9890-407: The other atmospheric effects of the impacts would be from Earth. Observers soon saw a huge dark spot after the first impact; the spot was visible from Earth. This and subsequent dark spots were thought to have been caused by debris from the impacts, and were markedly asymmetric, forming crescent shapes in front of the direction of impact. Over the next six days, 21 distinct impacts were observed, with

10005-426: The other hand, Pluto was considered to be a planet at the time of its discovery in 1930, as it was found beyond Neptune. Following this pattern, several hypothetical bodies were given names: Vulcan for a planet within the orbit of Mercury; Phaeton for a planet between Mars and Jupiter that was believed to be the precursor of the asteroids; Themis for a moon of Saturn; and Persephone , and several other names, for

10120-447: The past two centuries. Before any systematic naming convention was adopted, comets were named in a variety of ways. The first one to be named was " Halley's Comet " (now officially known as Comet Halley), named after Edmond Halley , who had calculated its orbit. Similarly, the second known periodic comet, Comet Encke (formally designated 2P/Encke), was named after the astronomer, Johann Franz Encke, who had calculated its orbit rather than

10235-456: The past. Names of people, companies or products known only for success in business are not accepted, nor are citations that resemble advertising. Whimsical names can be used for relatively ordinary asteroids (such as 26858 Misterrogers or 274301 Misplaced Pages ), but those belonging to certain dynamical groups are expected to follow more strictly defined naming schemes. The names given to comets have followed several different conventions over

10350-451: The planet once in approximately 500 years and those 1.6 km (1 mi) in diameter do so just once in every 6,000 years. There is very strong evidence that comets have previously been fragmented and collided with Jupiter and its satellites. During the Voyager missions to the planet, planetary scientists identified 13 crater chains on Callisto and three on Ganymede , the origin of which

10465-448: The planet. Observers hoped that the impacts would give them a first glimpse of Jupiter beneath the cloud tops, as lower material was exposed by the comet fragments punching through the upper atmosphere. Spectroscopic studies revealed absorption lines in the Jovian spectrum due to diatomic sulfur (S 2 ) and carbon disulfide (CS 2 ), the first detection of either in Jupiter, and only

10580-505: The planet. Cometary orbits around Jupiter are unstable, as they will be highly elliptical and likely to be strongly perturbed by the Sun's gravity at apojove (the farthest point on the orbit from the planet). By far the most massive planet in the Solar System , Jupiter can capture objects relatively frequently, but the size of SL9 makes it a rarity: one post-impact study estimated that comets 0.3 km (0.19 mi) in diameter impact

10695-444: The possibility of a collision became a certainty. The collision would provide a unique opportunity for scientists to look inside Jupiter's atmosphere, as the collisions were expected to cause eruptions of material from the layers normally hidden beneath the clouds. Astronomers estimated that the visible fragments of SL9 ranged in size from a few hundred metres (around 1,000 ft) to two kilometres (1.2 mi) across, suggesting that

10810-799: The prominent SN 1987A , was the first one to be observed in 1987, while SN 2023ixf was one of the brightest ever observed in recent times. Several thousand supernovae have been reported since 1885. In recent years, several supernova discovery projects have retained their more distant supernova discoveries for in-house follow-up, and not reported them to CBAT. Starting in 2015, CBAT has scaled back its efforts to publish assigned designations of typed supernovae: By September 2014, CBAT had published names and details of 100 supernovae discovered in that year. By September 2015, CBAT had only published names of 20 supernovae discovered in that year. The Astronomer's Telegram provides some surrogate services independent from CBAT. Four historical supernovae are known simply by

10925-592: The resolving power of telescopes increased, numerous objects that were thought to be a single object were found to be optical star systems that were too closely spaced in the sky to be discriminated by the human eye. This led to a third iteration, where numeric superscripts were added to distinguish those previously unresolved stars. Examples include Theta Sagittarii ( θ Sgr ) later distinguished as Theta¹ Sagittarii ( θ¹ Sgr ) and Theta² Sagittarii ( θ² Sgr ), each being their own (physical) star system with two and three stars, respectively. Flamsteed designations consist of

11040-772: The responsibility for naming minor planets lies with the Working Group Small Bodies Nomenclature (WGSBN, originally the Committee Small Bodies Nomenclature , CSBN, and before that the Minor Planet Names Committee , MPNC), which is composed of 15 members, 11 of whom are voting members, while the other four are representatives for the Working Group for Planetary System Nomenclature , the Minor Planet Center , as well as

11155-435: The second detection of S 2 in any astronomical object . Other molecules detected included ammonia (NH 3 ) and hydrogen sulfide (H 2 S). The amount of sulfur implied by the quantities of these compounds was much greater than the amount that would be expected in a small cometary nucleus, showing that material from within Jupiter was being revealed. Oxygen -bearing molecules such as sulfur dioxide were not detected, to

11270-417: The sky. At first, only the shapes of the patterns were defined, and the names and numbers of constellations varied from one star map to another. Despite being scientifically meaningless, they do provide useful reference points in the sky for human beings, including astronomers. In 1930, the boundaries of these constellations were fixed by Eugène Joseph Delporte and adopted by the IAU, so that now every point on

11385-406: The speed of light—into the Jovian magnetosphere by the impacts. About an hour after fragment K entered Jupiter, observers recorded auroral emission near the impact region, as well as at the antipode of the impact site with respect to Jupiter's strong magnetic field . The cause of these emissions was difficult to establish due to a lack of knowledge of Jupiter's internal magnetic field and of

11500-563: The star lies in, like the older Ptolemy 's Almagest in Greek from 150 and Al-Sufi 's Book of Fixed Stars in Arabic from 964. The variety of sky catalogues now in use means that most bright stars currently have multiple designations. In 1540, the Italian astronomer Piccolomini released the book De le Stelle Fisse (On the Fixed Stars) which include star maps of 47 constellations where he numbered

11615-433: The stars in a binary system, its name can be, for example, Kepler-34(AB) b . Earth's natural satellite is simply known as the Moon , or the equivalent in the language being spoken (for instance, two astronomers speaking French would call it la Lune ). English-language science fiction often adopts the Latin name "Luna" while using the English "Moon" as a term for natural satellites in general in order to better distinguish

11730-414: The stars in magnitude order using latin letters. The Bayer designations of about 1,500 brightest stars were first published in 1603. In this list, a star is identified by a lower-case letter of the Greek alphabet , followed by the Latin name of its parent constellation. The Bayer designation uses the possessive form of a constellation's name, which in almost every case ends in is , i or ae ; um if

11845-430: The surprise of astronomers. As well as these molecules , emission from heavy atoms such as iron , magnesium and silicon were detected, with abundances consistent with what would be found in a cometary nucleus. Although a substantial amount of water was detected spectroscopically, it was not as much as predicted, meaning that either the water layer thought to exist below the clouds was thinner than predicted, or that

11960-409: The time. Its orbit around Jupiter was very loosely bound, with a period of about 2 years and an apoapsis (the point in the orbit farthest from the planet) of 0.33 astronomical units (49 million kilometres; 31 million miles). Its orbit around the planet was highly eccentric ( e = 0.9986). Tracing back the comet's orbital motion revealed that it had been orbiting Jupiter for some time. It

12075-407: The train of nuclei would plow into Jupiter's atmosphere over a period of about five days. The discovery that the comet was likely to collide with Jupiter caused great excitement within the astronomical community and beyond, as astronomers had never before seen two significant Solar System bodies collide. Intense studies of the comet were undertaken, and as its orbit became more accurately established,

12190-864: The wider concept from any specific example. Natural satellites of other planets are generally named after mythological figures related to their parent body's namesake, such as Phobos and Deimos , the twin sons of Ares (Mars), or the Galilean moons of Io , Europa , Ganymede , and Callisto , four consorts of Zeus (Jupiter). Satellites of Uranus are instead named after characters from works by William Shakespeare or Alexander Pope , such as Umbriel or Titania . When natural satellites are first discovered, they are given provisional designations such as " S/2010 J 2 " (the 2nd new satellite of Jupiter discovered in 2010) or " S/2003 S 1 " (the 1st new satellite of Saturn discovered in 2003). The initial "S/" stands for "satellite", and distinguishes from such prefixes as "D/", "C/", and "P/", used for comets . The designation "R/"

12305-589: The year they occurred: SN 1006 (the brightest stellar event ever recorded), SN 1054 (of which the remnant is the Crab Nebula and the Crab Pulsar ), SN 1572 ( Tycho's Nova ), and SN 1604 ( Kepler's Star ). Since 1885, the letter-suffixes are explicitly assigned, regardless whether only one supernova is detected during the entire year (although this has not occurred since 1947). Driven by advances in technology and increases in observation time in

12420-409: Was clarified in 1958, when a committee of the IAU recommended for adoption the names of 128 albedo features (bright, dark, or colored) observed through ground-based telescopes (IAU, 1960). These names were based on a system of nomenclature developed in the late 19th century by the Italian astronomer Giovanni V. Schiaparelli (1879) and expanded in the early 20th century by Eugene M. Antoniadi (1929),

12535-518: Was completely unprecedented, astronomers were cautious with their predictions of what the event might reveal. Anticipation grew as the predicted date for the collisions approached, and astronomers trained terrestrial telescopes on Jupiter. Several space observatories did the same, including the Hubble Space Telescope , the ROSAT X-ray -observing satellite , the W. M. Keck Observatory , and

12650-546: Was designated S/2011 (134340) 1 rather than S/2011 P 1, though the New Horizons team, who disagreed with the dwarf planet classification, used the latter. After a few months or years, when a newly discovered satellite's existence has been confirmed and its orbit computed, a permanent name is chosen, which replaces the "S/" provisional designation. However, in the past, some satellites remained unnamed for surprisingly long periods after their discovery. See Naming of moons for

12765-463: Was initially a mystery. Crater chains seen on the Moon often radiate from large craters, and are thought to be caused by secondary impacts of the original ejecta, but the chains on the Jovian moons did not lead back to a larger crater. The impact of SL9 strongly implied that the chains were due to trains of disrupted cometary fragments crashing into the satellites. On July 19, 2009, exactly 15 years after

12880-403: Was that large, asymmetric ballistic fireballs would rise above the limb of Jupiter and into sunlight to be visible from Earth. Other suggested effects of the impacts were seismic waves travelling across the planet, an increase in stratospheric haze on the planet due to dust from the impacts, and an increase in the mass of the Jovian ring system . However, given that observing such a collision

12995-493: Was their eleventh comet discovery overall including their discovery of two non-periodic comets, which use a different nomenclature. The discovery was announced in IAU Circular 5725 on March 26, 1993. The discovery image gave the first hint that comet Shoemaker–Levy 9 was an unusual comet, as it appeared to show multiple nuclei in an elongated region about 50  arcseconds long and 10 arcseconds wide. Brian G. Marsden of

13110-515: Was therefore reclassified into a different class of astronomical bodies known as dwarf planets , along with Eris and others. Currently, according to the IAU, there is no agreed upon system for designating exoplanets (planets orbiting other stars). The process of naming them is organized by the IAU Executive Committee Working Group Public Naming of Planets and Planetary Satellites. The scientific nomenclature for

13225-538: Was violated once for the comet-asteroid 4015 Wilson–Harrington , whose name has 17 characters; this is because it had already been named as a comet before being rediscovered as an asteroid.) Letters with diacritics are accepted, although in English the diacritical marks are usually omitted in everyday usage. 4090 Říšehvězd is an asteroid with the most diacritics (four). Military and political leaders are unsuitable unless they have been dead for at least 100 years. Names of pet animals are discouraged, but there are some from

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