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WASP-33b
WASP-33b is an extrasolar planet orbiting the star HD 15082. It was the first planet discovered to orbit a Delta Scuti variable star. With a semimajor axis of and a mass likely greater than Jupiter's, it belongs to the hot Jupiter class of planets. Discovery In 2010, the SuperWASP project announced the discovery of an extrasolar planet orbiting the star HD 15082. The discovery was made by detecting the transit of the planet as it passes in front of its star, an event that occurs every 1.22 days. Orbit A study in 2012, utilizing the Rossiter–McLaughlin effect, determined the planetary orbit is strongly misaligned with the equatorial plane of the star, misalignment equal to −107.7°, making the orbit of WASP-33b retrograde. The periastron node is precessing with the period of 709 years. Physical characteristics Limits from radial velocity measurements imply it has less than 4.1 times the mass of Jupiter. The exoplanet orbits so close to its star that its surface tem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HD 15082
HD 15082 (also known as WASP-33) is a star located roughly 399 light years away in the northern constellation of Andromeda (constellation), Andromeda. The star is a Delta Scuti variable and a planetary transit variable. A hot Jupiter type Exoplanet, extrasolar planet, named WASP-33b or HD 15082b, orbits this star with an orbital period of 1.22 days. It is the first Delta Scuti variable known to host a planet. Spectrum HD 15082 is an Am star, which makes its stellar classification challenging to discern. The spectral lines, hydrogen lines and effective temperature of the star are similar to spectral type A8, however the calcium K-line, calcium II K line resembles that of an A5 star, and the metallic lines are more similar to an F4 star. The spectral type is written kA5hA8mF4. Pulsations Delta Scuti variables usually exhibit many Asteroseismology, pulsation modes, and HD 15082 is no exception, with 8 measured high frequency p-modes. Another proposed non-radial mode, w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydroxyl
In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical formula and composed of one oxygen atom covalently bonded to one hydrogen atom. In organic chemistry, alcohols and carboxylic acids contain one or more hydroxy groups. Both the negatively charged anion , called hydroxide, and the neutral radical , known as the hydroxyl radical, consist of an unbonded hydroxy group. According to IUPAC definitions, the term ''hydroxyl'' refers to the hydroxyl radical () only, while the functional group is called a ''hydroxy group''. Properties Water, alcohols, carboxylic acids, and many other hydroxy-containing compounds can be readily deprotonated due to a large difference between the electronegativity of oxygen (3.5) and that of hydrogen (2.1). Hydroxy-containing compounds engage in intermolecular hydrogen bonding increasing the electrostatic attraction between molecules and thus to higher boiling and melting points than found for compounds that lack this f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wide Angle Search For Planets
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 simultaneously, en ... [...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] |
Tests Of General Relativity
Tests of general relativity serve to establish observational evidence for the theory of general relativity. The first three tests, proposed by Albert Einstein in 1915, concerned the "anomalous" precession of the perihelion of Mercury, the bending of light in gravitational fields, and the gravitational redshift. The precession of Mercury was already known; experiments showing light bending in accordance with the predictions of general relativity were performed in 1919, with increasingly precise measurements made in subsequent tests; and scientists claimed to have measured the gravitational redshift in 1925, although measurements sensitive enough to actually confirm the theory were not made until 1954. A more accurate program starting in 1959 tested general relativity in the weak gravitational field limit, severely limiting possible deviations from the theory. In the 1970s, scientists began to make additional tests, starting with Irwin Shapiro's measurement of the relativistic time ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Newtonian Mechanics
Newton's laws of motion are three basic laws of classical mechanics that describe the relationship between the motion of an object and the forces acting on it. These laws can be paraphrased as follows: # A body remains at rest, or in motion at a constant speed in a straight line, unless acted upon by a force. # When a body is acted upon by a force, the time rate of change of its momentum equals the force. # If two bodies exert forces on each other, these forces have the same magnitude but opposite directions. The three laws of motion were first stated by Isaac Newton in his '' Philosophiæ Naturalis Principia Mathematica'' (''Mathematical Principles of Natural Philosophy''), originally published in 1687. Newton used them to investigate and explain the motion of many physical objects and systems, which laid the foundation for classical mechanics. In the time since Newton, the conceptual content of classical physics has been reformulated in alternative ways, involving differen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gravitational Field
In physics, a gravitational field is a model used to explain the influences that a massive body extends into the space around itself, producing a force on another massive body. Thus, a gravitational field is used to explain gravitational phenomena, and is measured in newtons per kilogram (N/kg). Equivalently, it is measured in meters per second squared (m/s2). In its original concept, gravity was a force between point masses. Following Isaac Newton, Pierre-Simon Laplace attempted to model gravity as some kind of radiation field or fluid, and since the 19th century, explanations for gravity have usually been taught in terms of a field model, rather than a point attraction. In a field model, rather than two particles attracting each other, the particles distort spacetime via their mass, and this distortion is what is perceived and measured as a "force". In such a model one states that matter moves in certain ways in response to the curvature of spacetime, and that there is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oblateness
Flattening is a measure of the compression of a circle or sphere along a diameter to form an ellipse or an ellipsoid of revolution (spheroid) respectively. Other terms used are ellipticity, or oblateness. The usual notation for flattening is and its definition in terms of the semi-axes of the resulting ellipse or ellipsoid is :: \mathrm = f =\frac . The ''compression factor'' is \frac\,\! in each case; for the ellipse, this is also its aspect ratio. Definitions There are three variants of flattening; when it is necessary to avoid confusion, the main flattening is called the first flattening.Torge, W. (2001). ''Geodesy'' (3rd edition). de Gruyter. and online web textsOsborne, P. (2008). The Mercator Projections'' Chapter 5.Rapp, Richard H. (1991). ''Geometric Geodesy, Part I''. Dept. of Geodetic Science and Surveying, Ohio State Univ., Columbus, Ohio/ref> In the following, is the larger dimension (e.g. semimajor axis), whereas is the smaller (semiminor axis). All flatt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astronomy & Astrophysics
''Astronomy & Astrophysics'' is a monthly peer-reviewed scientific journal covering theoretical, observational, and instrumental astronomy and astrophysics. The journal is run by a Board of Directors representing 27 sponsoring countries plus a representative of the European Southern Observatory. The journal is published by EDP Sciences and the editor-in-chief is . History Origins ''Astronomy and Astrophysics'' (A&A) was created as an answer to the publishing scenario found in Europe in the 1960s. At that time, multiple journals were being published in several countries around the continent. These journals usually had a limited number of subscribers, and published articles in languages other than English, resulting in a small number of citations compared to American and British journals. Starting in 1963, conversations between astronomers from European countries assessed the need for a common astronomical journal. On 8 April 1968, leading astronomers from Belgium, Denmark, Franc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Balmer Line
The Balmer series, or Balmer lines in atomic physics, is one of a set of six named series describing the spectral line emissions of the hydrogen atom. The Balmer series is calculated using the Balmer formula, an empirical equation discovered by Johann Balmer in 1885. The visible spectrum of light from hydrogen displays four wavelengths, 410 nm, 434 nm, 486 nm, and 656 nm, that correspond to emissions of photons by electrons in excited states transitioning to the quantum level described by the principal quantum number ''n'' equals 2. There are several prominent ultraviolet Balmer lines with wavelengths shorter than 400 nm. The number of these lines is an infinite continuum as it approaches a limit of 364.5 nm in the ultraviolet. After Balmer's discovery, five other hydrogen spectral series were discovered, corresponding to electrons transitioning to values of ''n'' other than two . Overview The Balmer series is characterized by the electron t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HARPS-N
HARPS-N, the ''High Accuracy Radial velocity Planet Searcher for the Northern hemisphere'' is a high-precision radial-velocity spectrograph, installed at the Italian Telescopio Nazionale Galileo, a 3.58-metre telescope located at the Roque de los Muchachos Observatory on the island of La Palma, Canary Islands, Spain. HARPS-N is the counterpart for the Northern Hemisphere of the similar HARPS instrument installed on the ESO 3.6 m Telescope at La Silla Observatory in Chile. It allows for planetary research in the northern sky which hosts the Cygnus and Lyra constellations. In particular it allows for detailed follow up research to Kepler mission planet candidates, which are located in the Cygnus constellation region. The instrument's main scientific goals are the discovery and characterization of terrestrial super-Earths by combining the measurements using transit photometry and doppler spectroscopy which provide both, the size and mass of the exoplanet. Based on the resulting dens ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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