|
Mu Persei
Mu Persei, Latinised from μ Persei, is a binary star system in the northern constellation of Perseus. It is visible to the naked eye as a point of light with a combined apparent visual magnitude of +4.16. The distance to this system is approximately 900 light-years based on parallax measurements. It is drifting further away with a radial velocity of +26 km/s. Mu Persei is a spectroscopic binary with an orbital period of 284 days and an eccentricity of about 0.06. The primary component is a yellow G-type supergiant star. With an effective temperature of about and a radius of 53 solar radii, this star has the luminosity of about 2,030 times that of the Sun. The companion is a B-type star with a class of B9.5 Mu Persei is moving through the galaxy at a speed of 35.6 km/s relative to the Sun. Its projected galactic orbit carries it between 23,900 and 32,400 light-years from the center of the galaxy. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
J2000
In astronomy, an epoch or reference epoch is a instant, 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 Astronomical object, celestial body, as they are subject to Perturbation (astronomy), 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 Perihelion and aphelion, 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 bodi ... [...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] |
Spectroscopic Binaries
A binary star is a system of two stars that are gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved using a telescope as separate stars, in which case they are called ''visual binaries''. Many visual binaries have long orbital periods of several centuries or millennia and therefore have orbits which are uncertain or poorly known. They may also be detected by indirect techniques, such as spectroscopy (''spectroscopic binaries'') or astrometry (''astrometric binaries''). If a binary star happens to orbit in a plane along our line of sight, its components will eclipse and transit each other; these pairs are called ''eclipsing binaries'', or, together with other binaries that change brightness as they orbit, ''photometric binaries''. If components in binary star systems are close enough they can gravitationally distort their mutual outer stellar atmospheres. In some cases, these ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
G-type Supergiants
Gaea Gaea is one of the Elder Gods of Earth. Gaia Gaia, also known as the Guardian of the Universal Amalgamator, is a fictional superhero, depicted as possibly being a mutant or extraterrestrial. Created by Larry Hama, she first appeared in ''Generation X'' #37. Not much is known about Gaia's origin besides her having spent thousands of years chained to the Universal Amalgamator at the end of Time, a device that would be used to merge all sentient consciousnesses into one being.''Generation X'' #37 Gaia was apparently the safeguard that was supposed to prevent the Amalgamator from being activated by malicious people. She even claimed that her entire galaxy was wiped out at one point for her refusing to activate the Amalgamator.''Generation X'' #38 However, when M-Plate, the synthesis of Emplate and M, tried to have Synch use his power to tap into Gaia's and activate the Amalgamator, Everett refused. The Citadel of the Universal Amalgamator began to crumble around them and G ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
48 Persei
48 Persei (also known as c Persei, 48 Per, HR 1273, HIP 19343, or ) is a Be star in the constellation Perseus, approximately the 500th brightest of the visible stars in apparent magnitude. It is "well known for its complex spectrum and for its light and velocity variations". The name "48 Persei" is a Flamsteed designation given to it by John Flamsteed in his catalogue, published in 1712. 48 Persei is classified as a Gamma Cassiopeiae variable, and it has been given the variable star designation MX Persei. The star's brightness varies by 0.09 magnitudes in visible light. Koen and Eyer examined the Hipparcos data for this star, and found it varied with a period of 5.0569 days. As a Be star, it is hot and blue, spinning so rapidly that it forms an unstable equatorial disk of matter surrounding it. Its mass has been estimated as seven times that of the Sun, and its estimated age of 40 million years makes it much younger than the Sun. In another few million years it will li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
δ Persei
Delta Persei (Delta Per, δ Persei, δ Per) is a double star in the northern constellation of Perseus. It has an apparent visual magnitude of 3.01, making it readily visible with the naked eye. Parallax measurements give it a distance of about from the Earth. The spectrum of this star matches a stellar classification of B5 III, which indicates it is a giant star that has evolved away from the main sequence after exhausting the hydrogen at its core. It has about seven times the Sun's mass and has an estimated age of 6.8 million years. The effective temperature of the outer envelope is 14,890 K, with the energy being emitted at this temperature giving it the blue-white hue that is a characteristic of a B-type star. It is rotating rapidly with a projected rotational velocity of 190 km s−1, which gives a lower bound for the actual azimuthal velocity along the star's equator. This is most probably a binary star and may be a triple star system. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ψ Persei
Psi Persei (Psi Per, ψ Persei, ψ Per) is a single Be star in the northern constellation of Perseus. It has an apparent visual magnitude of about 4.2, so it is visible to the naked eye at night under suitably dark skies. Based on parallax measurements, it is located at a distance of roughly from the Earth. Properties This star has a stellar classification of B5Ve, which indicates it is a B-type main sequence star that is generating energy at its core through the nuclear fusion of hydrogen. It is a shell star with a circumstellar disc of gas surrounding the equator and extending out to about 11 times the radius of the star. As a result of this disc, the spectrum of this star shows emission lines (as indicated by the 'e' in the stellar class) and its magnitude varies over a period 1.021 days. The General Catalog of Variable Stars classifies Psi Persei as a gamma Cassiopeiae variable star, whose visual band brightness varies from magnitude 4.17 to 4.28. Ps ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
α Persei
Alpha Persei ( Latinized from α Persei, abbreviated Alpha Per, α Per), formally named Mirfak (pronounced or ), is the brightest star in the northern constellation of Perseus, outshining the constellation's best-known star, Algol. Alpha Persei has an apparent visual magnitude of 1.8, and is a circumpolar star when viewed from mid-northern latitudes. Alpha Persei lies in the midst of a cluster of stars named as the eponymous Alpha Persei Cluster, or ''Melotte 20'', which is easily visible in binoculars and includes many of the fainter stars in the constellation. Determined distance using the trigonometric parallax, places the star from the Sun. Nomenclature ''α Persei'' is the star's Bayer designation. The star also bore the traditional names Mirfak and Algenib, which are Arabic in origin. The former, meaning 'Elbow' and also written Mirphak, Marfak or Mirzac, comes from the Arabic ''Mirfaq al-Thurayya'', while Algenib, also spelt Algeneb, Elgenab, G ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
γ Persei
Gamma Persei (Gamma Per, γ Persei, γ Per) is a binary star system in the constellation Perseus. The combined apparent visual magnitude of the pair is +2.9, making it the fourth-brightest member of the constellation. The distance to this system has been measured using the parallax technique, giving an estimate of roughly with a 4% margin of error. About 4° to the north of Gamma Persei is the radiance point for the annual Perseid meteor shower. This is a wide eclipsing binary system with an orbital period of 5,329.8 days (14.6 years). This eclipse was first observed in 1990 and lasted for two weeks. During an eclipse, the primary passes in front of the secondary, causing the magnitude of the system to decrease by 0.55. The primary component of this system is a giant star with a stellar classification of G9 III. It has a projected rotational velocity of 50.0 km s−1 and a lengthy estimated rotation period of 14.6 years. The classificat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
η Persei
Eta Persei (η Persei, abbreviated Eta Per, η Per), is a binary star and the 'A' component of a triple star system (the 'B' component is the star HD 237009) in the constellation of Perseus. It is approximately 1331 light-years away from Earth. The two components of Eta Persei itself are designated Eta Persei A (officially named Miram , a recent name for the system) and B. Nomenclature ''η Persei'' ( Latinised to ''Eta Persei'') is the binary star's Bayer designation. The designations of its two components as ''Eta Persei A'' and ''B'' derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU). Eta Persei mysteriously gained the named ''Miram'' in the 20th Century, though no source is known. In 2016, the IAU organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars. The WGSN decided to attribute proper names to individua ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asterism (astronomy)
An asterism is an observed pattern or group of stars in the sky. Asterisms can be any identified pattern or group of stars, and therefore are a more general concept than the formally defined 88 constellations. Constellations are based on asterisms, but unlike asterisms, constellations outline and today completely divide the sky and all its celestial objects into regions around their central asterisms. For example, the asterism known as the Big Dipper comprises the seven brightest stars in the constellation Ursa Major. Another is the asterism of the Southern Cross, within the constellation of Crux. Asterisms range from simple shapes of just a few stars to more complex collections of many stars covering large portions of the sky. The stars themselves may be bright naked-eye objects or fainter, even telescopic, but they are generally all of a similar brightness to each other. The larger brighter asterisms are useful for people who are familiarizing themselves with the night sky. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.svg "Click for more on -> Solar Luminosity")
