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List Of Stars In Lyra ...
This is the list of notable stars in the constellation Lyra, sorted by decreasing brightness. See also *List of stars by constellation References * * * * * {{Stars of Lyra *List Lyra Lyra (; Latin for lyre, from Greek ''λύρα'') is a small constellation. It is one of the 48 listed by the 2nd century astronomer Ptolemy, and is one of the modern 88 constellations recognized by the International Astronomical Union. Lyra was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Star
A star is an astronomical object comprising a luminous spheroid of plasma held together by its gravity. The nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night, but their immense distances from Earth make them appear as fixed points of light. The most prominent stars have been categorised into constellations and asterisms, and many of the brightest stars have proper names. Astronomers have assembled star catalogues that identify the known stars and provide standardized stellar designations. The observable universe contains an estimated to stars. Only about 4,000 of these stars are visible to the naked eye, all within the Milky Way galaxy. A star's life begins with the gravitational collapse of a gaseous nebula of material composed primarily of hydrogen, along with helium and trace amounts of heavier elements. Its total mass is the main factor determining its evolution and eventual fate. A star shines for most of its active life due t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Brightest Stars
This is a list of stars arranged by their apparent magnitude – their brightness as observed from Earth. It includes all stars brighter than magnitude +2.50 in visible light, measured using a ''V''-band filter in the UBV photometric system. Stars in binary systems (or other multiples) are listed by their ''total'' or ''combined'' brightness if they appear as a single star to the naked eye, or listed separately if they do not. As with all magnitude systems in astronomy, the scale is logarithmic and inverted i.e. lower/more negative numbers are brighter. Most stars on this list appear bright from Earth because they are nearby, not because they are intrinsically luminous. For a list which compensates for the distances, converting the ''apparent'' magnitude to the ''absolute'' magnitude, see the list of most luminous stars. Measurement The Sun is the brightest star as viewed from Earth, at −26.74 mag. The second brightest is Sirius at −1.46 mag. For compa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eta Lyrae
Eta Lyrae, a name Latinized from η Lyrae, is a likely binary star system in the northern constellation of Lyra. It has the traditional name Aladfar and is faintly visible to the naked eye with an apparent visual magnitude of 4.43. The system is located at a distance of approximately 1,390 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −8 km/s. Nomenclature ''η Lyrae'' ( Latinised to ''Eta Lyrae'') is the binary star's Bayer designation. Its designation as the ''A'' component of a double star, and of its two constituents as the ''Aa'' and ''Ab'' components, derives from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU). 'BD +38 3491' is the 'B' component's designation in the Bonner Durchmusterung astrometric star catalogue. Eta Lyrae bore the traditional name ''Aladfar'', from the Arabic ''الأظفر'' ''al-� ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Theta Lyrae
Theta Lyrae (θ Lyr) is a star in a trinary star system, in the constellation Lyra, approximately 770 light years away from Earth. Theta Lyrae is an orange bright giant star of the spectral type K0II, which means that it possesses a surface temperature of about 5,000 kelvins, and is many times bigger and brighter, yet cooler, than the Sun. It is orbited by a subsystem composed of BD+37° 3399 and BD+37° 3399B. 10th magnitude BD+37° 3399 is a giant star A giant star is a star with substantially larger radius and luminosity than a main sequence, main-sequence (or ''dwarf'') star of the same effective temperature, surface temperature.Giant star, entry in ''Astronomy Encyclopedia'', ed. Patrick Moo ... with a spectral type of K2III. It is therefore almost the same temperature as Theta Lyrae, but smaller and dimmer. BD+37° 3399B is an 11th magnitude star of an unknown spectral type. References {{Stars of Lyra Lyra (constellation) Lyrae, Theta Lyrae, 21 094713 180 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zeta1 Lyrae
Zeta1 Lyrae, Latinized from ζ1 Lyrae, is a binary star in the northern constellation of Lyra. Based upon an annual parallax shift of 20.89 mas as seen from Earth, the pair are located about 156 light years from the Sun. It is visible to the naked eye with an apparent visual magnitude of 4.37. Observational history ζ1 Lyrae was discovered to be a spectroscopic binary by William Wallace Campbell and Heber Doust Curtis in 1905 from photographic plates taken at the Lick Observatory between 1902 and 1904. The first orbit was calculated by Frank Craig Jordan of Allegheny Observatory in 1910 with results in good agreement with the most recent orbit. Several other faint stars within about an arc-minute have been listed as companions, but none are physically associated with ζ1 Lyrae. Binary system This is a single-lined spectroscopic binary system with an orbital period of 4.3 days and a nearly circular orbit with an eccentricity of 0.01. The prima ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kappa Lyrae
κ Lyrae, Latinized as Kappa Lyrae, is a solitary star in the northern constellation of Lyra, near the constellation border with Hercules. It is visible to the naked eye as a faint, orange-hued point of light with an apparent visual magnitude of 4.33. This object is located approximately 252 light years from the Sun based on parallax, but is moving closer with a radial velocity of −24 km/s. This is an aging giant star with a stellar classification of K2-IIIabCN0.5, with the suffix notation indicating a mild underabundance of cyanogen. Having exhausted the supply of hydrogen at its core, the star has cooled and expanded. It now has 18 times the Sun's girth and is radiating 127 times the luminosity of the Sun at an effective temperature of 4,638 K. κ Lyrae is a red clump giant, which means it is on the horizontal branch and is generating energy through core helium fusion. It is a suspected small amplitude variable star A variable star is a star who ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Delta2 Lyrae
Delta2 Lyrae (δ2 Lyr) is a 4th magnitude star in the constellation Lyra, approximately 900 light years away from Earth. It is one of the M4II spectral standard stars, meaning it is a bright giant star with a surface temperature around 3,600 kelvins. It puts out more energy than 10,000 suns, although more than 90% of it at longer than visual wavelengths. Direct angular measurements, combined with the Hipparcos parallax, give a radius of 1.1 - 1.3 astronomical units, comparable to the size calculated from other observed data. It began life as a hot blue main sequence star, but now is a large cool asymptotic giant branch star with a degenerate carbon-oxygen core. It is a semi-regular variable star that has its brightness change by 0.2 magnitudes over an ill-defined period. Delta2 Lyrae was once thought to form a visual binary with the star Delta1 Lyrae, but it does not, only appearing to do so if seen from earth's direction. δ2 Lyrae is a variable star, probab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semiregular Variable
In astronomy, a semiregular variable star, a type of variable star, is a giant or supergiant of intermediate and late (cooler) spectral type showing considerable periodicity in its light changes, accompanied or sometimes interrupted by various irregularities. Periods lie in the range from 20 to more than 2000 days, while the shapes of the light curves may be rather different and variable with each cycle. The amplitudes may be from several hundredths to several magnitudes (usually 1-2 magnitudes in the V filter). Classification The semiregular variable stars have been sub-divided into four categories for many decades, with a fifth related group defined more recently. The original definitions of the four main groups were formalised in 1958 at the tenth general assembly of the International Astronomical Union (IAU). The General Catalogue of Variable Stars (GCVS) has updated the definitions with some additional information and provided newer reference stars where old examples such a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
R Lyrae
R Lyrae, also known as its Flamsteed designation 13 Lyrae, is a 4th magnitude semiregular variable star in the constellation Lyra, approximately 350 light years away from Earth. It is a red giant star of the spectral type M5III, meaning it has a surface temperature of under 3,500 kelvins. It is much larger and brighter, yet cooler, than the Sun. In the near- infrared J band, it is brighter than the nearby Vega. R Lyrae is unusual in that it is a red star with a high proper motion, greater than 50 milliarcseconds a year. The variability is not consistent and regular, but periods of 46, 64, 378, and 1,000 days have been reported, with the 46-day period being the strongest. It is calculated that R Lyrae was a star on the main sequence. It is considered an oxygen-rich asymptotic giant branch The asymptotic giant branch (AGB) is a region of the Hertzsprung–Russell diagram populated by evolved cool luminous stars. This is a period of stellar evolution unde ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beta Lyrae Variable
Beta Lyrae variables are a class of close binary stars. Their total brightness is variable because the two component stars orbit each other, and in this orbit one component periodically passes in front of the other one, thereby blocking its light. The two component stars of Beta Lyrae systems are quite heavy (several solar masses () each) and extended ( giants or supergiants). They are so close, that their shapes are heavily distorted by mutual gravitation forces: the stars have ellipsoidal shapes, and there are extensive mass flows from one component to the other. Mass flows These mass flows occur because one of the stars, in the course of its evolution, has become a giant or supergiant. Such extended stars easily lose mass, just because they are so large: gravitation at their surface is weak, so gas easily escapes (the so-called stellar wind). In close binary systems such as beta Lyrae systems, a second effect reinforces this mass loss: when a giant star swells, it may reach ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beta Lyrae
Beta Lyrae (β Lyrae, abbreviated Beta Lyr, β Lyr) officially named Sheliak (Arabic: الشلياق, Romanization: ash-Shiliyāq) (IPA: ), the traditional name of the system, is a multiple star system in the constellation of Lyra. Based on parallax measurements obtained during the Hipparcos mission, it is approximately distant from the Sun. Although it appears as a single point of light to the naked eye, it actually consists of six components of apparent magnitude 14.3 or brighter. The brightest component, designated Beta Lyrae A, is itself a triple star system, consisting of an eclipsing binary pair (Aa) and a single star (Ab). The binary pair's two components are designated Beta Lyrae Aa1 and Aa2. The additional five components, designated Beta Lyrae B, C, D, E, and F, are currently considered to be single stars. Nomenclature ''β Lyrae'' ( Latinised to ''Beta Lyrae'') is the system's Bayer designation, established by Johann Bayer in his ''Uranometria'' of 1603, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Variable Star
A variable star is a star whose brightness as seen from Earth (its apparent magnitude) changes with time. This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are classified as either: * Intrinsic variables, whose luminosity actually changes; for example, because the star periodically swells and shrinks. * Extrinsic variables, whose apparent changes in brightness are due to changes in the amount of their light that can reach Earth; for example, because the star has an orbiting companion that sometimes eclipses it. Many, possibly most, stars have at least some variation in luminosity: the energy output of the Sun, for example, varies by about 0.1% over an 11-year solar cycle. Discovery An ancient Egyptian calendar of lucky and unlucky days composed some 3,200 years ago may be the oldest preserved historical document of the discovery of a variable star, the eclipsing binary Algol. Of the modern astronomers, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
