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μ Aurigae
Mu Aurigae, Latinized as μ Aurigae, is the Bayer designation for an unconfirmed binary star in the northern constellation of Auriga. It is visible to the naked eye with an apparent visual magnitude of +4.88. Based upon an annual parallax shift of as seen from Earth, is located 157 light-years from the Sun. This is an A-type main-sequence star with a stellar classification of A4 Vm; the 'm' suffix indicating that abnormal abundances of heavier elements appear in the star's spectrum, making this an Am star. It is 560 million years old with a projected rotational velocity of . It has double the mass of the Sun and is radiating 23 times the Sun's luminosity at an effective temperature of . A very close companion has been reported using speckle interferometry, but this remains unconfirmed. The separation at discovery in 1986 was and it was measured at in 1999. It was catalogued by ''Hipparcos'' as a problem binary, indicating that the measurements of its ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
J2000
In astronomy, an epoch or reference epoch is a moment in time used as a reference point for some time-varying astronomical quantity. It is useful for the celestial coordinates or orbital elements of a celestial body, as they are subject to perturbations and vary with time. These time-varying astronomical quantities might include, for example, the mean longitude or mean anomaly of a body, the node of its orbit relative to a reference plane, the direction of the apogee or aphelion of its orbit, or the size of the major axis of its orbit. The main use of astronomical quantities specified in this way is to calculate other relevant parameters of motion, in order to predict future positions and velocities. The applied tools of the disciplines of celestial mechanics or its subfield orbital mechanics (for predicting orbital paths and positions for bodies in motion under the gravitational effects of other bodies) can be used to generate an ephemeris, a table of values giving the positions ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Projected Rotational Velocity
Stellar rotation is the angular motion of a star about its axis. The rate of rotation can be measured from the spectrum of the star, or by timing the movements of active features on the surface. The rotation of a star produces an equatorial bulge due to centrifugal force. As stars are not solid bodies, they can also undergo differential rotation. Thus the equator of the star can rotate at a different angular velocity than the higher latitudes. These differences in the rate of rotation within a star may have a significant role in the generation of a stellar magnetic field. The magnetic field of a star interacts with the stellar wind. As the wind moves away from the star its rate of angular velocity slows. The magnetic field of the star interacts with the wind, which applies a drag to the stellar rotation. As a result, angular momentum is transferred from the star to the wind, and over time this gradually slows the star's rate of rotation. Measurement Unless a star is being obs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
φ Aurigae
Phi Aurigae, Latinized from φ Aurigae, is a giant star in the northern constellation of Auriga. It is faintly visible to the naked eye with an apparent visual magnitude of 5.089. It lies from another faint naked-eye star HD 35520, between the three open clusters M36 and M38, and NGC 1893. The distance to this star, as determined from parallax measurements, is approximately with a 10 light-year margin of error. This is an evolved giant star with a stellar classification of K3 IIIp and an estimated radius equal to 16 times the radius of the Sun. The outer envelope has an effective temperature of 4,367 K, giving it the cool orange-hued glow of a K-type star. References External links HR 1805CCDM J05277+3429Image Phi Aurigae {{DEFAULTSORT:Phi Aurigae 035620 058051 Aurigae, Phi Auriga (constellation) K-type giants Aurigae, 24 1805 After thirteen years the First French Empire abolished the French Republican Calendar in favour of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
19 Aurigae
19 Aurigae is a single star located approximately 3,800 light years away from the Sun in the northern constellation Auriga. It is visible to the naked eye as a faint, white-hued star with an apparent visual magnitude of 5.05. The star is moving closer to the Earth with a heliocentric radial velocity of 4.3 km/s. This is an evolved A-type bright giant star with a stellar classification of A5 II+. It is a variable star of unknown type that ranges in magnitude from 5.03 down to 5.09. This star is an estimated 36 million years old with a projected rotational velocity of 8 km/s. It has 8 times the mass of the Sun and about 15 times the Sun's radius. 19 Aurigae is radiating 7,057 times the total luminosity of the Sun from its photosphere at an effective temperature of 8,300 K. References External links HR 1740Image 19 Aurigae {{DEFAULTSORT:19 Aurigae A-type bright giants Auriga (constellation) Durchmusterung objects Aurigae, 19 034578 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Net (Chinese Constellation)
The Net mansion () is one of the Twenty-eight mansions of the Chinese constellations. It is one of the western mansions of the White Tiger (Chinese constellation), White Tiger. Asterisms References {{DEFAULTSORT:Net (Chinese Constellation) Chinese constellations ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chinese Language
Chinese (, especially when referring to written Chinese) is a group of languages spoken natively by the ethnic Han Chinese majority and many minority ethnic groups in Greater China. About 1.3 billion people (or approximately 16% of the world's population) speak a variety of Chinese as their first language. Chinese languages form the Sinitic branch of the Sino-Tibetan languages family. The spoken varieties of Chinese are usually considered by native speakers to be variants of a single language. However, their lack of mutual intelligibility means they are sometimes considered separate languages in a family. Investigation of the historical relationships among the varieties of Chinese is ongoing. Currently, most classifications posit 7 to 13 main regional groups based on phonetic developments from Middle Chinese, of which the most spoken by far is Mandarin (with about 800 million speakers, or 66%), followed by Min (75 million, e.g. Southern Min), Wu (74 million, e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Σ Aurigae
Sigma Aurigae, Latinized from σ Aurigae, is a giant star in the northern constellation of Auriga. It is faintly visible to the naked eye with an apparent visual magnitude of 4.99. With an annual parallax shift of 6.21 mas, it is approximately distant from the Earth. This is an evolved giant star with a stellar classification of K4 III. Sigma Aurigae has a 12th magnitude companion at an angular separation of 8 arcseconds, as well as two fainter companions at 28 and 35" respectively. All are background objects, stars much further away than Sigma itself. Sigma Aurigae, along with λ Aur and μ Aur, were Kazwini's ''Al Ḣibāʽ'' (ألحباع), the Tent. According to the catalogue of stars in the ''Technical Memorandum 33-507 – A Reduced Star Catalog Containing 537 Named Stars'', ''Al Ḣibāʽ'' were the title for three stars: λ Aur as ''Al Ḣibāʽ I'', μ Aur as ''Al Ḣibāʽ II'' and σ Aur as ''Al Ḣibāʽ III''. References External link ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Λ Aurigae
Lambda Aurigae, Latinized from λ Aurigae, is the Bayer designation for a solar analog star in the northern constellation of Auriga. It is visible to the naked eye with an apparent visual magnitude of 4.71. Based upon parallax measurements, it is approximately distant from the Earth. The star is drifting further away with a high radial velocity of +66.5 km/s, having come to within some 117,300 years ago. It has a high proper motion, traversing the celestial sphere at the rate of per year. Properties This is a G-type main sequence star with a stellar classification of G1 V. It is sometimes listed with a class of G1.5 IV-V Fe-1, which indicates the spectrum is showing some features of a more evolved subgiant star along with a noticeable underabundance of iron. In terms of composition it is similar to the Sun, while the mass and radius are slightly larger. It is 73% more luminous than the Sun and radiates this energy from its outer atmospher ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ρ Aurigae
Rho Aurigae (ρ Aur, ρ Aurigae) is the Bayer designation for a binary star system in the northern constellation of Auriga. It is faintly visible to the naked eye with an apparent visual magnitude of +5.22. Judging by parallax measurements, this system is approximately distant from the Earth, give or take a 30-light-year margin of error. System ρ Aurigae is a single-lined spectroscopic binary system; the presence of a companion object is revealed by shifts in the stellar spectrum. The pair orbit each other with a period of 34.49 days and an orbital eccentricity of 0.10. The primary component of this system is a B-type main-sequence star defined as a standard star for the stellar classification of B5 V. The deduced mass of the secondary and the lack of evidence for it in the spectrum suggest it may be a B- or A-type star somewhat less luminous than the primary. Name In Chinese, (), meaning '' Pool of Harmony'', refers to an asterism consisting of ρ A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lambda Aurigae
Lambda Aurigae, Latinized from λ Aurigae, is the Bayer designation for a solar analog star in the northern constellation of Auriga. It is visible to the naked eye with an apparent visual magnitude of 4.71. Based upon parallax measurements, it is approximately distant from the Earth. The star is drifting further away with a high radial velocity of +66.5 km/s, having come to within some 117,300 years ago. It has a high proper motion, traversing the celestial sphere at the rate of per year. Properties This is a G-type main sequence star with a stellar classification of G1 V. It is sometimes listed with a class of G1.5 IV-V Fe-1, which indicates the spectrum is showing some features of a more evolved subgiant star along with a noticeable underabundance of iron. In terms of composition it is similar to the Sun, while the mass and radius are slightly larger. It is 73% more luminous than the Sun and radiates this energy from its outer atmosphere ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hipparcos
''Hipparcos'' was a scientific satellite of the European Space Agency (ESA), launched in 1989 and operated until 1993. It was the first space experiment devoted to precision astrometry, the accurate measurement of the positions of celestial objects on the sky. This permitted the first high-precision measurements of the intrinsic brightnesses (compared to the less precise apparent brightness), proper motions, and parallaxes of stars, enabling better calculations of their distance and tangential velocity. When combined with radial velocity measurements from spectroscopy, astrophysicists were able to finally measure all six quantities needed to determine the motion of stars. The resulting ''Hipparcos Catalogue'', a high-precision catalogue of more than 118,200 stars, was published in 1997. The lower-precision ''Tycho Catalogue'' of more than a million stars was published at the same time, while the enhanced Tycho-2 Catalogue of 2.5 million stars was published in 2000. ''Hipparcos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Speckle Interferometry
Speckle imaging describes a range of high-resolution astronomical imaging techniques based on the analysis of large numbers of short exposures that freeze the variation of atmospheric turbulence. They can be divided into the shift-and-add ("''image stacking''") method and the speckle interferometry methods. These techniques can dramatically increase the resolution of ground-based telescopes, but are limited to bright targets. Explanation The principle of all the techniques is to take very short exposure images of astronomical targets, and then process those so as to remove the effects of astronomical seeing. Use of these techniques led to a number of discoveries, including thousands of binary stars that would otherwise appear as a single star to a visual observer working with a similar-sized telescope, and the first images of sunspot-like phenomena on other stars. Many of the techniques remain in wide use today, notably when imaging relatively bright targets. The resolution ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
