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List Of Stars With Proplyds
This is a list of stars with proplyds (ionized protoplanetary discs) and includes whether they have gaps or planets. Lists of proplyds List of proplyds with gaps ''(list is very incomplete)'' ''When planets are confirmed (if no planet before), please move to the List of extrasolar planets'' List of proplyds without gaps :''(list is very incomplete)'' List of extremes This list contains the largest, smallest, oldest, youngest. :''(list is very incomplete)'' List of firsts This list contains firsts. :''(list is very incomplete)'' See also * Hypothetical astronomical object * List of exoplanet extremes * Lists of astronomical objects * Lists of exoplanets These are lists of exoplanets. Most of these were discovered by the Kepler space telescope. There are an additional 2,054 potential exoplanets from Kepler's first mission yet to be confirmed, as well as 978 from its " Second Light" mission and ... References External links * SpaceDailyNASA's Spitzer Digs U ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proplyd
A proplyd, short for ionized protoplanetary disk, is an externally illuminated photoevaporating protoplanetary disk around a young star. Nearly 180 proplyds have been discovered in the Orion Nebula. Images of proplyds in other star-forming regions are rare, while Orion is the only region with a large known sample due to its relative proximity to Earth. History In 1979 observations with the Lallemand electronic camera at the Pic-du-Midi Observatory showed six unresolved high-ionization sources near the Trapezium Cluster. These sources were not interpreted as proplyds, but as partly ionized globules (PIGs). The idea was that these objects are being ionized from the outside by M42. Later observations with the Very Large Array showed solar-system-sized condensations associated with these sources. Here the idea appeared that these objects might be low-mass stars surrounded by an evaporating protostellar accretion disk. Proplyds were clearly resolved in 1993 using images of the Hu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
4U 0142+61
4U 0142+61 is a magnetar at an approximate distance of from Earth, located in the constellation Cassiopeia. In an article published in ''Nature'' on April 6, 2006, Deepto Chakrabarty ''et al.'' of MIT revealed that a circumstellar disk was discovered around the pulsar. This may prove that pulsar planets are common around neutron stars. The debris disk is likely to be composed of mainly heavier metals. The star had undergone a supernova event approximately 100,000 years ago. The disk orbits about 1.6 million kilometers away from the pulsar and probably contains about 10 Earth-masses of material. This also marks the first time that a pulsar has been discovered with a debris disk orbiting it. In May 2022, the first study by the IXPE space observatory hinted at the possibility of vacuum birefringence A vacuum is a space devoid of matter. The word is derived from the Latin adjective ''vacuus'' for "vacant" or "void". An approximation to such vacuum is a region with a g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lists Of Stars
The following are lists of stars. These are astronomical objects that spend some portion of their existence generating energy through thermonuclear fusion. By location * Lists of stars by constellation By name * List of traditional star names * List of Arabic star names * List of Chinese star names * Stars named after people By proximity * List of nearest stars and brown dwarfs (up to 20 light-years) * List of star systems within 20–25 light-years * List of star systems within 25–30 light-years * List of star systems within 30–35 light-years * List of star systems within 35–40 light-years * List of star systems within 40–45 light-years * List of star systems within 45–50 light-years * List of star systems within 50–55 light-years * List of star systems within 55–60 light-years * List of star systems within 60–65 light-years * List of star systems within 65–70 light-years * List of star systems within 70–75 light-years * List of star systems within ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lists Of Exoplanets
These are lists of exoplanets. Most of these were discovered by the Kepler space telescope. There are an additional 2,054 potential exoplanets from Kepler's first mission yet to be confirmed, as well as 978 from its "Second Light" mission and 4,081 from the Transiting Exoplanet Survey Satellite (TESS) mission. For yearly lists on physical, orbital and other properties, as well as on discovery circumstances and other aspects, ''see ''. Nomenclature Methods of detection Specific exoplanet lists Lists of exoplanets *List of directly imaged exoplanets *List of exoplanets discovered before 2000 () *List of exoplanets discovered between 2000–2009 () *List of exoplanets discovered in 2010 () * List of exoplanets discovered in 2011 () *List of exoplanets discovered in 2012 () *List of exoplanets discovered in 2013 () *List of exoplanets discovered in 2014 () * List of exoplanets discovered in 2015 () *List of exoplanets discovered in 2016 () *List of exoplanets discovered in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lists Of Astronomical Objects
This is a list of lists, grouped by type of astronomical object. Solar System * List of Solar System objects * List of gravitationally rounded objects of the Solar System * List of Solar System objects most distant from the Sun * List of Solar System objects by size * Lists of geological features of the Solar System * List of natural satellites (moons) * Lists of small Solar System bodies * Lists of comets * List of meteor showers ; Minor planets * List of minor planets ** List of exceptional asteroids ** List of minor planet moons ** List of damocloids ** List of centaurs (small Solar System bodies) ** List of trans-Neptunian objects ** List of unnumbered minor planets ** List of dwarf planets ** List of possible dwarf planets Exoplanets and brown dwarfs * Lists of planets * Lists of exoplanets ** List of largest exoplanets * List of brown dwarfs Stars *Lists of stars **List of nearest stars and brown dwarfs **List of brightest stars **List of hottest stars **Lis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Exoplanet Extremes
The following are lists of extremes among the known exoplanets. The properties listed here are those for which values are known reliably. It is important to note that the study of exoplanets is one of the most dynamic emerging fields of science, and these values may change wildly as new discoveries are made. Extremes from Earth's viewpoint Planetary characteristics Orbital characteristics Stellar characteristics System characteristics See also * Extremes on Earth * Lists of exoplanets * List of exoplanet firsts * List of stars with proplyds * Methods of detecting exoplanets * List of potentially habitable exoplanets References External links * WiredScienceTop 5 Most Extreme Exoplanets Clara Moskowitz, 21 January 2009 {{DEFAULTSORT:List of Extrasolar Planet Extremes *Planetary extremes Extrasolar planet extremes Extrasolar planet extremes Extremes exoplanets An exoplanet or extrasolar planet is a planet outside the Solar System. The first possible evidence ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypothetical Astronomical Object
Various unknown astronomical objects have been hypothesized throughout recorded history. For example, in the 5th century BCE, the philosopher Philolaus defined a hypothetical astronomical object which he called the " Central Fire", around which he proposed other celestial bodies (including the Sun) moved.Marco Ceccarelli, ''Distinguished Figures in Mechanism and Machine Science'' (2007), p. 124. Types of hypothetical astronomical objects Hypothetical astronomical objects have been speculated to exist both inside and outside of the Solar System, and speculation has included different kinds of stars, planets, and other astronomical objects. * For hypothetical astronomical objects in the Solar System, see: List of hypothetical Solar System objects * For hypothetical stars, see: Hypothetical star * For hypothetical brown dwarfs, see: List of brown dwarfs * For hypothetical black holes, see: Hypothetical black hole * For extrasolar moons, all of which are currently hypothetical, se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vega
Vega is the brightest star in the northern constellation of Lyra. It has the Bayer designation α Lyrae, which is Latinised to Alpha Lyrae and abbreviated Alpha Lyr or α Lyr. This star is relatively close at only from the Sun, and one of the most luminous stars in the Sun's neighborhood. It is the fifth-brightest star in the night sky, and the second-brightest star in the northern celestial hemisphere, after Arcturus. Vega has been extensively studied by astronomers, leading it to be termed "arguably the next most important star in the sky after the Sun". Vega was the northern pole star around 12,000 BCE and will be so again around the year 13,727, when its declination will be . Vega was the first star other than the Sun to have its image and spectrum photographed. It was one of the first stars whose distance was estimated through parallax measurements. Vega has functioned as the baseline for calibrating the photometric brightness scale and was one of the st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulsar
A pulsar (from ''pulsating radio source'') is a highly magnetized rotating neutron star that emits beams of electromagnetic radiation out of its magnetic poles. This radiation can be observed only when a beam of emission is pointing toward Earth (similar to the way a lighthouse can be seen only when the light is pointed in the direction of an observer), and is responsible for the pulsed appearance of emission. Neutron stars are very dense and have short, regular rotational periods. This produces a very precise interval between pulses that ranges from milliseconds to seconds for an individual pulsar. Pulsars are one of the candidates for the source of ultra-high-energy cosmic rays. (See also centrifugal mechanism of acceleration.) The periods of pulsars make them very useful tools for astronomers. Observations of a pulsar in a binary neutron star system were used to indirectly confirm the existence of gravitational radiation. The first extrasolar planets were discovered aroun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TW Hydrae
TW Hydrae is a T Tauri star approximately 196 light-years away in the constellation of Hydra (the Sea Serpent). TW Hydrae is about 80% of the mass of the Sun, but is only about 5-10 million years old. The star appears to be accreting from a face-on protoplanetary disk of dust and gas, which has been resolved in images from the ALMA observatory. TW Hydrae is accompanied by about twenty other low-mass stars with similar ages and spatial motions, comprising the "TW Hydrae association" or TWA, one of the closest regions of recent "fossil" star-formation to the Sun. Stellar characteristics TW Hydrae is a pre-main-sequence star that is approximately 80% the mass of and 111% the radius of the Sun. It has a temperature of 4000 K and is about 8 million years old. In comparison, the Sun is about 4.6 billion years old and has a temperature of 5778 K. The star's luminosity is 28% (0.28x) that of the Sun, equivalent to that of a main-sequence star of spectral type ~ K2. However, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protoplanetary Discs
A protoplanetary disk is a rotating circumstellar disc of dense gas and dust surrounding a young newly formed star, a T Tauri star, or Herbig Ae/Be star. The protoplanetary disk may also be considered an accretion disk for the star itself, because gases or other material may be falling from the inner edge of the disk onto the surface of the star. This process should not be confused with the accretion process thought to build up the planets themselves. Externally illuminated photo-evaporating protoplanetary disks are called proplyds. Formation Protostars form from molecular clouds consisting primarily of molecular hydrogen. When a portion of a molecular cloud reaches a critical size, mass, or density, it begins to collapse under its own gravity. As this collapsing cloud, called a solar nebula, becomes denser, random gas motions originally present in the cloud average out in favor of the direction of the nebula's net angular momentum. Conservation of angular momentum causes th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OTS 44
OTS 44 is a free-floating planetary-mass object or brown dwarf located at in the constellation Chamaeleon near the reflection nebula IC 2631. It is among the lowest-mass free-floating substellar objects, with approximately 11.5 times the mass of Jupiter, or approximately 1.1% that of the Sun. Its radius is not very well known and is estimated to be 23–57% that of the Sun. OTS 44 was discovered in 1998 by Oasa, Tamura, and Sugitani as a member of the star-forming region Chamaeleon I. Based upon infrared observations with the Spitzer Space Telescope and the Herschel Space Observatory, OTS 44 emits an excess of infrared radiation for an object of its type, suggesting it has a circumstellar disk of dust and particles of rock and ice. This disk has a mass of at least 10 Earth masses. Observations with the SINFONI spectrograph at the Very Large Telescope show that the disk is accreting matter at the rate of approximately 10−11 of the mass of the Sun per year. It could e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
