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Beta Pictoris B
Beta Pictoris b (abbreviated as β Pic b) is an exoplanet orbiting the young debris disk A-type main sequence star Beta Pictoris located approximately 63 light-years (19.4 parsecs, or km) away from Earth in the constellation of Pictor. It has a mass around 13 Jupiter masses and a radius around 46% larger than Jupiter's. It orbits at 9 AU from Beta Pictoris, which is about 3.5 times farther than the orbit of Beta Pictoris c. It orbits close to the plane of the debris disk orbiting the star, with a low eccentricity and a period of 20–21 years. Physical characteristics Mass, radius and temperature Beta Pictoris b is a super-Jupiter, an exoplanet that has a radius and mass greater than that of the planet Jupiter. It has a temperature of , most likely due to its dusty atmosphere and mass (normally it would be much colder). It has a mass of between 9 and 13 Jupiter masses (), and a radius of 1.46 . In 2018, a study directly measured the astrometric perturbation of Beta Pictoris ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Very Large Telescope
The Very Large Telescope (VLT) is a telescope facility operated by the European Southern Observatory on Cerro Paranal in the Atacama Desert of northern Chile. It consists of four individual telescopes, each with a primary mirror 8.2 m across, which are generally used separately but can be used together to achieve very high angular resolution. The four separate optical telescopes are known as ''Antu'', ''Kueyen'', ''Melipal'', and ''Yepun'', which are all words for astronomical objects in the Mapuche language. The telescopes form an array complemented by four movable Auxiliary Telescopes (ATs) of 1.8 m aperture. The VLT operates at visible and infrared wavelengths. Each individual telescope can detect objects roughly four billion times fainter than can be detected with the naked eye, and when all the telescopes are combined, the facility can achieve an angular resolution of about 0.002 arcsecond. In single telescope mode of operation angular resolution is about 0.05 arcs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Star
A star is an astronomical object comprising a luminous spheroid of plasma held together by its gravity. The nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night, but their immense distances from Earth make them appear as fixed points of light. The most prominent stars have been categorised into constellations and asterisms, and many of the brightest stars have proper names. Astronomers have assembled star catalogues that identify the known stars and provide standardized stellar designations. The observable universe contains an estimated to stars. Only about 4,000 of these stars are visible to the naked eye, all within the Milky Way galaxy. A star's life begins with the gravitational collapse of a gaseous nebula of material composed primarily of hydrogen, along with helium and trace amounts of heavier elements. Its total mass is the main factor determining its evolution and eventual fate. A star shines for most of its active life due t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Point Source
A point source is a single identifiable ''localised'' source of something. A point source has negligible extent, distinguishing it from other source geometries. Sources are called point sources because in mathematical modeling, these sources can usually be approximated as a mathematical point to simplify analysis. The actual source need not be physically small, if its size is negligible relative to other length scales in the problem. For example, in astronomy, stars are routinely treated as point sources, even though they are in actuality much larger than the Earth. In three dimensions, the density of something leaving a point source decreases in proportion to the inverse square of the distance from the source, if the distribution is isotropic, and there is no absorption or other loss. Mathematics In mathematics, a point source is a singularity from which flux or flow is emanating. Although singularities such as this do not exist in the observable universe, mathematical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chile
Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east and the Pacific Ocean to the west. Chile covers an area of , with a population of 17.5 million as of 2017. It shares land borders with Peru to the north, Bolivia to the north-east, Argentina to the east, and the Drake Passage in the far south. Chile also controls the Pacific islands of Juan Fernández, Isla Salas y Gómez, Desventuradas, and Easter Island in Oceania. It also claims about of Antarctica under the Chilean Antarctic Territory. The country's capital and largest city is Santiago, and its national language is Spanish. Spain conquered and colonized the region in the mid-16th century, replacing Inca rule, but failing to conquer the independent Mapuche who inhabited what is now south-central Chile. In 1818, after ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anne-Marie Lagrange
Anne-Marie Lagrange, born in the Rhône-Alpes region of France, is a French astrophysicist. Lagrange's work focuses on the research and study of extrasolar planetary systems. Lagrange is the holder of numerous scientific awards and honorary decorations, including Knight of the Legion of Honour (the highest French order of merit) and is a member of the French Academy of Sciences since 2013. Early life and education Anne-Marie Lagrange was born on 12 March 1962 in the Rhône-Alpes region where her father was employed at the French electric utility company, Électricité de France S.A. and a stay-at-home mother. When she was 5 years old, her father was transferred to Ain and the family moved to Ceyzérieu where Lagrange went to primary school. She attended college in Culoz, at the Lycée du Bugey in Belley. In high school, she was passionate about physics and mathematics and decided to study higher. On the advice of her teacher and the local Rotary Club, she went to Class ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stellar Flux
In radiometry, radiant flux or radiant power is the radiant energy emitted, reflected, transmitted, or received per unit time, and spectral flux or spectral power is the radiant flux per unit frequency or wavelength, depending on whether the spectrum is taken as a function of frequency or of wavelength. The SI unit of radiant flux is the watt (W), one joule per second (), while that of spectral flux in frequency is the watt per hertz () and that of spectral flux in wavelength is the watt per metre ()—commonly the watt per nanometre (). Mathematical definitions Radiant flux Radiant flux, denoted Φe ('e' for "energetic", to avoid confusion with photometric quantities), is defined as \Phi_\mathrm = \frac :Q_\mathrm = \int_ \mathbf\cdot \hat\mathbf\, dA where *''t'' is the time; *''Q''e is the radiant energy flux of the field out of a closed surface \Sigma; *S is the Poynting vector, representing the current density of radiant energy; *n is the normal vector of a point on \Sigma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saturn
Saturn is the sixth planet from the Sun and the second-largest in the Solar System, after Jupiter. It is a gas giant with an average radius of about nine and a half times that of Earth. It has only one-eighth the average density of Earth; however, with its larger volume, Saturn is over 95 times more massive. Saturn's interior is most likely composed of a core of iron–nickel and rock (silicon and oxygen compounds). Its core is surrounded by a deep layer of metallic hydrogen, an intermediate layer of liquid hydrogen and liquid helium, and finally, a gaseous outer layer. Saturn has a pale yellow hue due to ammonia crystals in its upper atmosphere. An electrical current within the metallic hydrogen layer is thought to give rise to Saturn's planetary magnetic field, which is weaker than Earth's, but which has a magnetic moment 580 times that of Earth due to Saturn's larger size. Saturn's magnetic field strength is around one-twentieth of Jupiter's. The outer atmosphere is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astronomical Unit
The astronomical unit (symbol: au, or or AU) is a unit of length, roughly the distance from Earth to the Sun and approximately equal to or 8.3 light-minutes. The actual distance from Earth to the Sun varies by about 3% as Earth orbits the Sun, from a maximum ( aphelion) to a minimum ( perihelion) and back again once each year. The astronomical unit was originally conceived as the average of Earth's aphelion and perihelion; however, since 2012 it has been defined as exactly (see below for several conversions). The astronomical unit is used primarily for measuring distances within the Solar System or around other stars. It is also a fundamental component in the definition of another unit of astronomical length, the parsec. History of symbol usage A variety of unit symbols and abbreviations have been in use for the astronomical unit. In a 1976 resolution, the International Astronomical Union (IAU) had used the symbol ''A'' to denote a length equal to the ast ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apparent Magnitude
Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's light caused by interstellar dust along the line of sight to the observer. The word ''magnitude'' in astronomy, unless stated otherwise, usually refers to a celestial object's apparent magnitude. The magnitude scale dates back to the ancient Roman astronomer Claudius Ptolemy, whose star catalog listed stars from 1st magnitude (brightest) to 6th magnitude (dimmest). The modern scale was mathematically defined in a way to closely match this historical system. The scale is reverse logarithmic: the brighter an object is, the lower its magnitude number. A difference of 1.0 in magnitude corresponds to a brightness ratio of \sqrt /math>, or about 2.512. For example, a star of magnitude 2.0 is 2.512 times as bright as a star of magnitude 3.0 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Astronomical Journal
''The Astronomical Journal'' (often abbreviated ''AJ'' in scientific papers and references) is a peer-reviewed monthly scientific journal owned by the American Astronomical Society (AAS) and currently published by IOP Publishing. It is one of the premier journals for astronomy in the world. Until 2008, the journal was published by the University of Chicago Press on behalf of the AAS. The reasons for the change to the IOP were given by the society as the desire of the University of Chicago Press to revise its financial arrangement and their plans to change from the particular software that had been developed in-house. The other two publications of the society, the ''Astrophysical Journal'' and its supplement series, followed in January 2009. The journal was established in 1849 by Benjamin A. Gould. It ceased publication in 1861 due to the American Civil War, but resumed in 1885. Between 1909 and 1941 the journal was edited in Albany, New York. In 1941, editor Benjamin Boss arrange ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metallicity
In astronomy, metallicity is the abundance of elements present in an object that are heavier than hydrogen and helium. Most of the normal physical matter in the Universe is either hydrogen or helium, and astronomers use the word ''"metals"'' as a convenient short term for ''"all elements except hydrogen and helium"''. This word-use is distinct from the conventional chemical or physical definition of a metal as an electrically conducting solid. Stars and nebulae with relatively high abundances of heavier elements are called "metal-rich" in astrophysical terms, even though many of those elements are nonmetals in chemistry. The presence of heavier elements hails from stellar nucleosynthesis, where the majority of elements heavier than hydrogen and helium in the Universe (''metals'', hereafter) are formed in the cores of stars as they evolve. Over time, stellar winds and supernovae deposit the metals into the surrounding environment, enriching the interstellar medium and provid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Universe Today
Universe Today (U.T.) is a popular North American-based non-commercial space and astronomy news website. The domain was registered on December 30, 1998, and the website went live in March 1999, founded by Canadian Fraser Cain. The ''Universe Today'' assumed its current form on July 24, 2003, featuring astronomy news and space-related issues. By early September 2005, the forum section merged with '' Bad Astronomy'' as a combined site with the BAUT forum. During April 2011, the Association of British Science Writers noted that ''Universe Today'' decided not to make preparations for reporting on embargoed stories until they are public knowledge. Emily Lakdawalla said that she relies on ''Universe Today'' and '' Bad Astronomy'' to "give ... an independent look at big news stories". Publications ''Universe Today'' has published two books, which are available both as e-book An ebook (short for electronic book), also known as an e-book or eBook, is a book publication made av ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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