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HIP 36616
HD 59686 is a binary star system in the northern constellation of Gemini. It is visible to the naked eye as a dim point of light with an apparent visual magnitude of +5.45. The distance to this system is approximately 292 light years based on parallax, but it is drifting closer with a radial velocity of −34 km/s. This is a single-lined spectroscopic binary system with an orbital period of and a high eccentricity of 0.73. The visible component is an aging giant star with a stellar classification of K2III, meaning it has ceased fusing hydrogen in its core and on its way to becoming a red giant. The stellar radius is very large: 11.2 times that of the Sun. The star is around 2.7 billion years old with 1.4 times the mass of the Sun. It is radiating 58 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,670 K. The secondary component has a minimum mass 53% that of the Sun, which indicates it must be a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gemini (constellation)
Gemini is one of the constellations of the zodiac and is located in the northern celestial hemisphere. It was one of the 48 constellations described by the 2nd century AD astronomer Ptolemy, and it remains one of the 88 modern constellations today. Its name is Latin for ''twins'', and it is associated with the twins Castor and Pollux in Greek mythology. Its old astronomical symbol is (♊︎). Location Gemini lies between Taurus to the west and Cancer to the east, with Auriga and Lynx to the north, Monoceros and Canis Minor to the south and Orion to the south-west. In classical antiquity, Cancer was the location of the Sun on the first day of summer (June 21). During the first century AD, axial precession shifted it into Gemini. In 1990, the location of the Sun on the first day of summer moved from Gemini into Taurus, where it will remain until the 27th century AD and then move into Aries. The Sun will move through Gemini from June 21 to July 20 through 2062. Gemini i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Effective Temperature
The effective temperature of a body such as a star or planet is the temperature of a black body that would emit the same total amount of electromagnetic radiation. Effective temperature is often used as an estimate of a body's surface temperature when the body's emissivity curve (as a function of wavelength) is not known. When the star's or planet's net emissivity in the relevant wavelength band is less than unity (less than that of a black body), the actual temperature of the body will be higher than the effective temperature. The net emissivity may be low due to surface or atmospheric properties, including greenhouse effect. Star The effective temperature of a star is the temperature of a black body with the same luminosity per ''surface area'' () as the star and is defined according to the Stefan–Boltzmann law . Notice that the total (bolometric) luminosity of a star is then , where is the stellar radius. The definition of the stellar radius is obviously not straightf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
K-type Giants , an unusual kind of asteroid
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K-type may refer to: *AEC K-type, a bus chassis *K-type star, a stellar spectral classification *K-type filter, a type of electronic filter *K-type asteroid K-type asteroids are relatively uncommon asteroids with a moderately reddish spectrum shortwards of 0.75 μm, and a slight bluish trend longwards of this. They have a low albedo. Their spectrum resembles that of CV and CO meteorites. A larger K t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bulletin Of The American Astronomical Society
''Bulletin of the American Astronomical Society'' (''BAAS''; ''Bull. Am. Astron. Soc.'') is the journal of record for the American Astronomical Society established in 1969. It publishes meetings of the society, obituaries of its members, and scholarly articles. Four issues are published per year that are collected into a single volume. Articles are indexed, and often archived, from the Astrophysics Data System The SAO/NASA Astrophysics Data System (ADS) is an online database of over 16 million astronomy and physics papers from both peer reviewed and non-peer reviewed sources. Abstracts are available free online for almost all articles, and full scanned a ..., using the journal code BAAS. External links * Publications established in 1969 Astronomy journals English-language journals Quarterly journals American Astronomical Society academic journals {{astronomy-journal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HD 59686 B
HD 59686 Ab is an exoplanet that orbits the giant star HD 59686 A in a close binary star system. It has a nearly circular orbit with a period of 300 days and a semi-major axis of 1.09 AU, slightly greater than the distance between Earth and the Sun. It has a minimum mass 6.9 times that of Jupiter, with the true mass depending on the orbital inclination, which is not yet known. HD 59686 Ab was discovered by radial velocity and first announced in November 2003, but the discovery was not formally published until 2016. HD 59686, along with Nu Octantis, is one of the closest binary star systems known to host a planet orbiting a single star (i.e., not a circumbinary planet A circumbinary planet is a planet that orbits two stars instead of one. The two stars orbit each other in a binary system, while the planet typically orbits farther from the center of the system than either of the two stars. In contrast, circums ...), posing a challenge to theories of planet formation. Refe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbital Eccentricity
In astrodynamics, the orbital eccentricity of an astronomical object is a dimensionless parameter that determines the amount by which its orbit around another body deviates from a perfect circle. A value of 0 is a circular orbit, values between 0 and 1 form an elliptic orbit, 1 is a parabolic escape orbit (or capture orbit), and greater than 1 is a hyperbola. The term derives its name from the parameters of conic sections, as every Kepler orbit is a conic section. It is normally used for the isolated two-body problem, but extensions exist for objects following a rosette orbit through the Galaxy. Definition In a two-body problem with inverse-square-law force, every orbit is a Kepler orbit. The eccentricity of this Kepler orbit is a non-negative number that defines its shape. The eccentricity may take the following values: * circular orbit: ''e'' = 0 * elliptic orbit: 0 < ''e'' < 1 * [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stellar Wobble
Doppler spectroscopy (also known as the radial-velocity method, or colloquially, the wobble method) is an indirect method for finding extrasolar planets and brown dwarfs from radial-velocity measurements via observation of Doppler shifts in the spectrum of the planet's parent star. 1,018 extrasolar planets (about 19.5% of the total) have been discovered using Doppler spectroscopy, as of November 2022. History Otto Struve proposed in 1952 the use of powerful spectrographs to detect distant planets. He described how a very large planet, as large as Jupiter, for example, would cause its parent star to wobble slightly as the two objects orbit around their center of mass. He predicted that the small Doppler shifts to the light emitted by the star, caused by its continuously varying radial velocity, would be detectable by the most sensitive spectrographs as tiny redshifts and blueshifts in the star's emission. However, the technology of the time produced radial-velocity meas ... [...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] |
Semimajor Axis
In geometry, the major axis of an ellipse is its longest diameter: a line segment that runs through the center and both foci, with ends at the two most widely separated points of the perimeter. The semi-major axis (major semiaxis) is the longest semidiameter or one half of the major axis, and thus runs from the centre, through a focus, and to the perimeter. The semi-minor axis (minor semiaxis) of an ellipse or hyperbola is a line segment that is at right angles with the semi-major axis and has one end at the center of the conic section. For the special case of a circle, the lengths of the semi-axes are both equal to the radius of the circle. The length of the semi-major axis of an ellipse is related to the semi-minor axis's length through the eccentricity and the semi-latus rectum \ell, as follows: The semi-major axis of a hyperbola is, depending on the convention, plus or minus one half of the distance between the two branches. Thus it is the distance from the center t ... [...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] |
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_\oplu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mass
Mass is an intrinsic property of a body. It was traditionally believed to be related to the quantity of matter in a physical body, until the discovery of the atom and particle physics. It was found that different atoms and different elementary particles, theoretically with the same amount of matter, have nonetheless different masses. Mass in modern physics has multiple definitions which are conceptually distinct, but physically equivalent. Mass can be experimentally defined as a measure of the body's inertia, meaning the resistance to acceleration (change of velocity) when a net force is applied. The object's mass also determines the strength of its gravitational attraction to other bodies. The SI base unit of mass is the kilogram (kg). In physics, mass is not the same as weight, even though mass is often determined by measuring the object's weight using a spring scale, rather than balance scale comparing it directly with known masses. An object on the Moon would weigh le ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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