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Epsilon Reticuli Ab
Epsilon Reticuli b, sometimes designated Epsilon Reticuli Ab to distinguish from the white dwarf companion of the primary star Epsilon Reticuli, also known as HD 27442, was discovered on December 16, 2000 by the Anglo-Australian Planet Search Team using the radial velocity method. The planet's mass is at least 56% greater than Jupiter mass, a more accurate estimate requiring its inclination to be known. The planet orbits its parent star relatively close, and with more than twice the eccentricity of Earth's orbit. Based on its mass, it is almost certainly a gas giant A gas giant is a giant planet composed mainly of hydrogen and helium. Gas giants are also called failed stars because they contain the same basic elements as a star. Jupiter and Saturn are the gas giants of the Solar System. The term "gas giant" .... References External links * The Extrasolar Planets Encyclopaedia [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chris Tinney
Chris Tinney is an astronomer at the University of New South Wales who is focused on extrasolar planet and brown dwarf research. He is a member of the Anglo-Australian Planet Search team which has discovered over twenty planets by doppler spectroscopy. He is also the former head of astronomy at the Anglo-Australian Observatory The Australian Astronomical Observatory (AAO), formerly the Anglo-Australian Observatory, was an optical and near-infrared astronomy observatory with its headquarters in North Ryde in suburban Sydney, Australia. Originally funded jointly by the U .... External links homepage 20th-century Australian astronomers Living people 21st-century Australian astronomers Year of birth missing (living people) Place of birth missing (living people) {{Astronomer-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geoffrey Marcy
Geoffrey William Marcy (born September 29, 1954) is an American astronomer. He was an early influence in the field of exoplanet detection, discovery, and characterization. Marcy was a professor of astronomy at the University of California, Berkeley, and an adjunct professor of physics and astronomy at San Francisco State University. Marcy and his research teams discovered many extrasolar planets, including 70 out of the first 100 known exoplanets and also the first planetary system around a Sun-like star, Upsilon Andromedae. Marcy was a co-investigator on the NASA Kepler (spacecraft), ''Kepler'' mission. His collaborators have included R. Paul Butler, Debra Fischer and Steven S. Vogt, Jason Wright, Andrew Howard, Katie Peek, John Johnson (astronomer), John Johnson, Erik Petigura, Lauren Weiss, Lea Hirsch and the Kepler Science Team. Early life and education Marcy graduated from Granada Hills High School in Granada Hills, California, in 1972. He graduated with a Bachelor of Arts ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anglo-Australian Observatory
The Australian Astronomical Observatory (AAO), formerly the Anglo-Australian Observatory, was an optical and near-infrared astronomy observatory with its headquarters in North Ryde in suburban Sydney, Australia. Originally funded jointly by the United Kingdom and Australian governments, it was managed wholly by Australia's Department of Industry, Innovation, Science, Research and Tertiary Education. The AAO operated the 3.9-metre Anglo-Australian Telescope (AAT) and 1.2-metre UK Schmidt Telescope (UKST) at Siding Spring Observatory, located near the town of Coonabarabran, Australia. In addition to operating the two telescopes, AAO staff carried out astronomical research, and designed and built astronomical instrumentation for the AAT, UKST, and other telescopes including the European Southern Observatory (ESO)'s Very Large Telescope in Chile, and the Japanese Subaru Telescope on Mauna Kea in Hawaii. UK involvement in the AAO ceased in June 2010, with the change of name and mana ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radial Velocity
The radial velocity or line-of-sight velocity, also known as radial speed or range rate, of a target with respect to an observer is the rate of change of the distance or range between the two points. It is equivalent to the vector projection of the target-observer relative velocity onto the relative direction connecting the two points. In astronomy, the point is usually taken to be the observer on Earth, so the radial velocity then denotes the speed with which the object moves away from the Earth (or approaches it, for a negative radial velocity). Formulation Given a differentiable vector \mathbf \in \mathbb^3 defining the instantaneous position of a target relative to an observer. Let with \mathbf \in \mathbb^3, the instantaneous velocity of the target with respect to the observer. The magnitude of the position vector \mathbf is defined as The quantity range rate is the time derivative of the magnitude ( norm) of \mathbf, expressed as Substituting () into () : ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epsilon Reticuli
Epsilon Reticuli, Latinized from ε Reticuli, is a double star approximately 59 light-years away in the constellation of Reticulum. The primary component is an orange subgiant, while the secondary is a white dwarf. The two stars share a common motion through space and hence most likely form a binary star system. The brighter star should be easily visible without optical aid under dark skies in the southern hemisphere. In 2000, an extrasolar planet was confirmed to be orbiting the primary star in the system. Star system The primary component, Epsilon Reticuli A, is a subgiant star with a stellar classification of K2IV, indicating that the fusing of hydrogen in its core is coming to an end and it is in the process of expanding to a red giant. With an estimated mass of about 1.5 times the solar mass, it was probably an F0 star while in the main sequence. It has a radius of 3.18 times the solar radius, a luminosity of 6.2 the solar luminosity and an effecti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
White Dwarf
A white dwarf is a stellar core remnant composed mostly of electron-degenerate matter. A white dwarf is very dense: its mass is comparable to the Sun's, while its volume is comparable to the Earth's. A white dwarf's faint luminosity comes from the emission of residual thermal energy; no fusion takes place in a white dwarf. The nearest known white dwarf is at 8.6 light years, the smaller component of the Sirius binary star. There are currently thought to be eight white dwarfs among the hundred star systems nearest the Sun. The unusual faintness of white dwarfs was first recognized in 1910. The name ''white dwarf'' was coined by Willem Luyten in 1922. White dwarfs are thought to be the final evolutionary state of stars whose mass is not high enough to become a neutron star or black hole. This includes over 97% of the other stars in the Milky Way. After the hydrogen- fusing period of a main-sequence star of low or medium mass ends, such a star will expand to a red gi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anglo-Australian Planet Search
The Anglo Australian Planet Search or (AAPS) is a long-term astronomical survey started in 1998 and continuing to the present. It is being carried out on the 3.9-metre Anglo-Australian Telescope (AAT) of the Anglo-Australian Observatory in Australia. The purpose of this survey is to catalog planets around more than 240 nearby stars of the southern hemisphere. For its observations, the AAT uses the ''University College London Echelle Spectrograph'', UCLES, an echelle spectrograph from the University College London located at the telescope's coudé focus. This survey uses the radial velocity method to search for extrasolar planets. The survey eventually switched its main focus to detecting long-period Jupiter analogs.The Anglo-Australian Planet Search. XXIII. Two New Jupiter Analogs Robert A. Witten ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radial Velocity
The radial velocity or line-of-sight velocity, also known as radial speed or range rate, of a target with respect to an observer is the rate of change of the distance or range between the two points. It is equivalent to the vector projection of the target-observer relative velocity onto the relative direction connecting the two points. In astronomy, the point is usually taken to be the observer on Earth, so the radial velocity then denotes the speed with which the object moves away from the Earth (or approaches it, for a negative radial velocity). Formulation Given a differentiable vector \mathbf \in \mathbb^3 defining the instantaneous position of a target relative to an observer. Let with \mathbf \in \mathbb^3, the instantaneous velocity of the target with respect to the observer. The magnitude of the position vector \mathbf is defined as The quantity range rate is the time derivative of the magnitude ( norm) of \mathbf, expressed as Substituting () into () : ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jupiter Mass
Jupiter mass, also called Jovian mass, is the unit of mass equal to the total mass of the planet Jupiter. This value may refer to the mass of the planet alone, or the mass of the entire Jovian system to include the moons of Jupiter. Jupiter is by far the most massive planet in the Solar System. It is approximately 2.5 times as massive as all of the other planets in the Solar System combined. Jupiter mass is a common unit of mass in astronomy that is used to indicate the masses of other similarly-sized objects, including the outer planets, extrasolar planets, and brown dwarfs, as this unit provides a convenient scale for comparison. Current best estimates The current best known value for the mass of Jupiter can be expressed as : :M_\mathrm=(1.89813 \pm 0.00019)\times10^ \text, which is about as massive as the sun (is about ): :M_\mathrm=\frac M_ \approx (9.547919 \pm 0.000002) \times10^ M_. Jupiter is 318 times as massive as Earth: :M_\mathrm = 3.1782838 \times 10^2 M_\op ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inclination
Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a Plane of reference, reference plane and the orbital plane or Axis of rotation, axis of direction of the orbiting object. For a satellite orbiting the Earth directly above the Equator, the plane of the satellite's orbit is the same as the Earth's equatorial plane, and the satellite's orbital inclination is 0°. The general case for a circular orbit is that it is tilted, spending half an orbit over the northern hemisphere and half over the southern. If the orbit swung between 20° north latitude and 20° south latitude, then its orbital inclination would be 20°. Orbits The inclination is one of the six orbital elements describing the shape and orientation of a celestial orbit. It is the angle between the orbital plane and the plane of reference, normally stated in degree (angle), degrees. For a satellite orbiting a planet, the plane of reference is usually ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gas Giant
A gas giant is a giant planet composed mainly of hydrogen and helium. Gas giants are also called failed stars because they contain the same basic elements as a star. Jupiter and Saturn are the gas giants of the Solar System. The term "gas giant" was originally synonymous with "giant planet". However, in the 1990s, it became known that Uranus and Neptune are really a distinct class of giant planets, being composed mainly of heavier volatile substances (which are referred to as "ices"). For this reason, Uranus and Neptune are now often classified in the separate category of ice giants. Jupiter and Saturn consist mostly of hydrogen and helium, with heavier elements making up between 3 and 13 percent of their mass.The Interior of Jupiter, Guillot et al., in ''Jupiter: The Planet, Satellites and Magnetosphere'', Bagenal et al., editors, Cambridge University Press, 2004 They are thought to consist of an outer layer of compressed molecular hydrogen surrounding a layer of liquid metalli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reticulum
Reticulum is a small, faint constellation in the southern sky. Its name is Latin for a small net, or reticle—a net of crosshairs at the focus of a telescope eyepiece that is used to measure star positions. The constellation is best viewed between October and December, and save for one main star visible in ideal conditions, cannot be seen from north of the 30th parallel north. History A constellation in this area was introduced by Isaac Habrecht II in his celestial globe in 1621, who named it ''Rhombus''. It was replaced with a somewhat different constellation by the French astronomer Nicolas Louis de Lacaille in the eighteenth century; during his stay at the Cape of Good Hope, he named the constellation le Réticule Rhomboide to commemorate the reticle in his telescope eyepiece. The name was later Latinized to Reticulum in his star catalogue ''Coelum Australe Stelliferum''. In 1810, the stars of Reticulum were used by William Croswell to produce the constellation ''Marmor S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
