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WASP-15
WASP-15, also named Nyamien, is a magnitude 11 star located about 1000 light-years away in the constellation Centaurus. The star, which is more massive, larger, hotter, and more luminous than the Sun, is also less metal-rich than the Sun. WASP-15 has one known planet in its orbit, WASP-15b; the planet is a Hot Jupiter with an anomalously high radius, a phenomenon which may be explained by the presence of an internal heat source. The star was first observed by the SuperWASP program in 2006; future measurements in 2007 and 2008, as well as follow-up observations and analysis, eventually led to the discovery of WASP-15b using the transit method and Doppler spectroscopy. Observational history WASP-15 was first observed from the South African Astronomical Observatory, which hosts the planet-searching SuperWASP program in the Southern Hemisphere (WASP-South), and was catalogued by its brightness and its coordinates in the sky. This information was captured first with one camera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
WASP-15b
WASP-15b, formally named Asye, is an extrasolar planet discovered in 2008 by the SuperWASP collaboration, which seeks to discover exoplanets that transit their host stars. The planet orbits its host star at a distance of 0.05 AU every four days. The mass of this planet is about one half that of Jupiter, but its radius is nearly 50% larger than Jupiter's, making the density of this planet only one quarter that of water; it is thought that some other form of heating must explain its extremely low density. WASP-15b's discovery was published on April 29, 2009. Discovery WASP-15 was first observed by the WASP-South branch of the SuperWASP project, which operates from the South African Astronomical Observatory, between May 4, 2006, and July 17, 2006. It was later observed by WASP-South from January 31, 2007, to July 17, 2007, and from January 31, 2008, to May 29, 2008. Further analysis taken from 24,943 collected data points revealed eleven full or partial transits. Follow-up observat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SuperWASP
WASP or Wide Angle Search for Planets is an international consortium of several academic organisations performing an ultra-wide angle search for exoplanets using transit photometry. The array of robotic telescopes aims to survey the entire sky, simultaneously monitoring many thousands of stars at an apparent visual magnitude from about 7 to 13. WASP is the detection program composed of the Isaac Newton Group, IAC and six universities from the United Kingdom. The two continuously operating, robotic observatories cover the Northern and Southern Hemisphere, respectively. SuperWASP-North is at Roque de los Muchachos Observatory on the mountain of that name which dominates La Palma in the Canary Islands. WASP-South is at the South African Astronomical Observatory, Sutherland in the arid Roggeveld Mountains of South Africa. These use eight wide-angle cameras that simultaneously monitor the sky for planetary transit events and allow the monitoring of millions of stars simultaneousl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CORALIE Spectrograph
Leonhard Euler Telescope, or the Swiss EULER Telescope, is a national, fully automatic reflecting telescope, built and operated by the Geneva Observatory. It is located at an altitude of at ESO's La Silla Observatory site in the Chilean Norte Chico region, about 460 kilometers north of Santiago de Chile. The telescope, which saw its first light on 12 April 1998, is named after Swiss mathematician Leonhard Paul Euler. The Euler telescope uses the CORALIE instrument to search for exoplanets. In addition, the telescope uses the multi-purpose EulerCam (ecam), a high precision photometry instrument, and a smaller, piggyback mounted telescope, called "Pisco". Its first discovery was a planet in orbit around Gliese 86, determined to be a hot Jupiter with an orbital period of only 15.8 earth days and about four times the mass of Jupiter. Since then, many other exoplanets have been discovered or examined in follow-up observations. Together with the Mercator Telescope, Euler was part o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EulerCam
Leonhard Euler Telescope, or the Swiss EULER Telescope, is a national, fully automatic reflecting telescope, built and operated by the Geneva Observatory. It is located at an altitude of at ESO's La Silla Observatory site in the Chilean Norte Chico region, about 460 kilometers north of Santiago de Chile. The telescope, which saw its first light on 12 April 1998, is named after Swiss mathematician Leonhard Paul Euler. The Euler telescope uses the CORALIE instrument to search for exoplanets. In addition, the telescope uses the multi-purpose EulerCam (ecam), a high precision photometry instrument, and a smaller, piggyback mounted telescope, called "Pisco". Its first discovery was a planet in orbit around Gliese 86, determined to be a hot Jupiter with an orbital period of only 15.8 earth days and about four times the mass of Jupiter. Since then, many other exoplanets have been discovered or examined in follow-up observations. Together with the Mercator Telescope, Euler was part of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leonhard Euler Telescope
Leonhard Euler Telescope, or the Swiss EULER Telescope, is a national, fully automatic reflecting telescope, built and operated by the Geneva Observatory. It is located at an altitude of at ESO's La Silla Observatory site in the Chilean Norte Chico region, about 460 kilometers north of Santiago de Chile. The telescope, which saw its first light on 12 April 1998, is named after Swiss mathematician Leonhard Paul Euler. The Euler telescope uses the CORALIE instrument to search for exoplanets. In addition, the telescope uses the multi-purpose EulerCam (ecam), a high precision photometry instrument, and a smaller, piggyback mounted telescope, called "Pisco". Its first discovery was a planet in orbit around Gliese 86, determined to be a hot Jupiter with an orbital period of only 15.8 earth days and about four times the mass of Jupiter. Since then, many other exoplanets have been discovered or examined in follow-up observations. Together with the Mercator Telescope, Euler was part o ... [...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, 6. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Light Year
A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 (one million million, or billion in long scale). As defined by the International Astronomical Union (IAU), a light-year is the distance that light travels in a vacuum in one Julian year (365.25 days). Because it includes the time-measurement word "year", the term ''light-year'' is sometimes misinterpreted as a unit of time. The ''light-year'' is most often used when expressing distances to stars and other distances on a galactic scale, especially in non-specialist contexts and popular science publications. The unit most commonly used in professional astronomy is the parsec (symbol: pc, about 3.26 light-years) which derives from astrometry; it is the distance at which one astronomical unit subtends an angle of one second of arc. Defini ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parsec
The parsec (symbol: pc) is a unit of length used to measure the large distances to astronomical objects outside the Solar System, approximately equal to or (au), i.e. . The parsec unit is obtained by the use of parallax and trigonometry, and is defined as the distance at which 1 au subtends an angle of one arcsecond ( of a degree). This corresponds to astronomical units, i.e. 1\, \mathrm = 1/\tan \left( \ \mathrm \right)\, \mathrm. The nearest star, Proxima Centauri, is about from the Sun. Most stars visible to the naked eye are within a few hundred parsecs of the Sun, with the most distant at a few thousand. The word ''parsec'' is a portmanteau of "parallax of one second" and was coined by the British astronomer Herbert Hall Turner in 1913 to make calculations of astronomical distances from only raw observational data easy for astronomers. Partly for this reason, it is the unit preferred in astronomy and astrophysics, though the light-year remains prominent in popular s ... [...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 astronomical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Luminosity
The solar luminosity (), is a unit of radiant flux (power emitted in the form of photons) conventionally used by astronomers to measure the luminosity of stars, galaxies and other celestial objects in terms of the output of the Sun. One nominal solar luminosity is defined by the International Astronomical Union to be . This does not include the solar neutrino luminosity, which would add , or , i.e. a total of (the mean energy of the solar photons is 26 MeV and that of the solar neutrinos 0.59 MeV, i.e. 2.27%; the Sun emits photons and as many neutrinos each second, of which per m2 reach the Earth each second). The Sun is a weakly variable star, and its actual luminosity therefore fluctuates. The major fluctuation is the eleven-year solar cycle (sunspot cycle) that causes a quasi-periodic variation of about ±0.1%. Other variations over the last 200–300 years are thought to be much smaller than this. Determination Solar luminosity is related to solar irradiance (the solar c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tidal Heating
Tidal heating (also known as tidal working or tidal flexing) occurs through the tidal friction processes: orbital and rotational energy is dissipated as heat in either (or both) the surface ocean or interior of a planet or satellite. When an object is in an elliptical orbit, the tidal forces acting on it are stronger near periapsis than near apoapsis. Thus the deformation of the body due to tidal forces (i.e. the tidal bulge) varies over the course of its orbit, generating internal friction which heats its interior. This energy gained by the object comes from its gravitational energy, so over time in a two-body system, the initial elliptical orbit decays into a circular orbit (tidal circularization). Sustained tidal heating occurs when the elliptical orbit is prevented from circularizing due to additional gravitational forces from other bodies that keep tugging the object back into an elliptical orbit. In this more complex system, gravitational energy still is being converted to ther ... [...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 providing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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