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Eta Capricorni
Eta Capricorni, Latinized from η Capricorni, is a binary star system in the southern constellation of Capricornus. It can be seen with the naked eye, having a combined apparent visual magnitude of +4.84. Based upon an annual parallax shift of 20.20 mas as seen from the Earth, the star is located about 161 light years from the Sun. The pair orbit each other with a period of 27.85 years, a semimajor axis of 0.265 arc seconds, an eccentricity of 0.410. The primary member, component A, is a white-hued A-type main sequence star with an apparent magnitude of +5.02. Its companion, component B, has an apparent magnitude of +7.39. Nomenclature ''η Capricorni'' ( Latinised to ''Eta Capricorni'') is the system's Bayer designation. It also has the Flamsteed designation 22 Capricorni. In Chinese, (), meaning '' Twelve States'', refers to an asterism which is represent twelve ancient states in the Spring and Autumn period and the Warring States period, cons ... [...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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Light Year
A light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distance, astronomical distances and is equal to exactly , which is approximately 9.46 trillion km or 5.88 trillion mi. As defined by the International Astronomical Union (IAU), a light-year is the distance that Speed of light, light travels in vacuum in one Julian year (astronomy), Julian year (365.25 days). Despite its inclusion of the word "year", the term should not be misinterpreted as a unit of time. The ''light-year'' is most often used when expressing distances to stars and other distances on a Galaxy, galactic scale, especially in public understanding of science, non-specialist contexts and popular science publications. The unit most commonly used in professional astronomy is the parsec (symbol: pc, about 3.26 light-years). Definitions As defined by the International Astronomical Union (IAU), the light-year is the product of the Julian year (astronomy), Julian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
38 Capricorni '', 2001
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38 may refer to: *38 (number) *38 BC *AD 38 *1938 *2038 Science * Strontium, an alkaline earth metal in the periodic table * 38 Leda, an asteroid in the asteroid belt Other uses *.38, a caliber of firearms and cartridges ** .38 Special, a revolver cartridge *'' Thirty-Eight: The Hurricane That Transformed New England'', a 2016 book by Stephen Long *"Thirty Eight", a song by Karma to Burn from the album ''Almost Heathen ''Almost Heathen'' is the third studio album by the stoner rock band Karma to Burn. It was released on September 4, 2001, by Spitfire Records. It was the last album released before their seven-year disbandment in 2002. The album was reissued in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iota Capricorni
Iota Capricorni (ι Cap, ι Capricorni) is a solitary, yellow-hued star in the southern constellation of Capricornus. It can be seen with the naked eye, having an apparent visual magnitude of +4.3. Based upon an annual parallax shift of 16.2 mas as seen from the Earth, the star is located about 201 light years from the Sun. At that distance, the visual magnitude of the star is diminished by an extinction factor of 0.08 due to interstellar dust. This is an evolved G-type giant star with a stellar classification of G8 III. It is classified as a BY Draconis type variable star. This is a chromospherically-active star with a longitudinal magnetic field strength of and an X-ray luminosity of . The activity and photometric variation of the star allow an estimate of its rotation period as 68 days. Iota Capricorni has an estimated 2.9 times the mass of the Sun and nearly 11 times the Solar radius. It is 390 million years old and is radiating 83 times ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phi Capricorni
Phi Capricorni (φ Cap, φ Capricorni) is a solitary star in the southern constellation of Capricornus. It is visible to the naked eye with an apparent visual magnitude of +5.16. Based upon an annual parallax shift of 5.07 mas as seen from the Earth, the star is located about 640 light years from the Sun, give or take 30 light years. This is an evolved, orange-hued K-type giant/bright giant star with a stellar classification of K0 II-III It shows an infrared excess, which may be due to leftover material from a mass-loss event. The star has an estimated 2.63 times the mass of the Sun, and radiates 447 times the solar luminosity from its photosphere at an effective temperature of 4,490 K. Phi Capricorni is around 1.24 billion years old and is spinning with a projected rotational velocity of 3.8 km/s. Chinese Name In Chinese, (), meaning '' Twelve States'', refers to an asterism which is represent twelve ancient states in the Spring and Autumn p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Warring States Period
The Warring States period in history of China, Chinese history (221 BC) comprises the final two and a half centuries of the Zhou dynasty (256 BC), which were characterized by frequent warfare, bureaucratic and military reforms, and struggles for greater hegemonic influence among the ancient Chinese states, various autonomous feudal states of the Eastern Zhou dynasty. It followed the Spring and Autumn period and concluded with the eventual unification of China by the western state of Qin (state), Qin under Qin Shi Huang, who Qin's wars of unification, conquered all other contender states by 221 BC and found the Qin dynasty, the first history of China#Imperial China, imperial dynasty in East Asian history. While scholars have identified several different dates as marking the beginning of the Warring States period, Sima Qian's choice of 475 BC, the first year of King Yuan of Zhou's reign, is the most often cited due to the paucity of preceding annals after th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spring And Autumn Period
The Spring and Autumn period () was a period in History of China, Chinese history corresponding roughly to the first half of the Eastern Zhou (256 BCE), characterized by the gradual erosion of royal power as local lords nominally subject to the Zhou exercised increasing political autonomy. The period's name derives from the ''Spring and Autumn Annals'', a chronicle of the state of Lu between 722 and 481 BCE, which tradition associates with Confucius (551–479 BCE). During this period, local polities negotiated their own alliances, waged wars against one another, up to defying the king's court in Luoyang, Luoyi. The gradual Partition of Jin, one of the most powerful states, is generally considered to mark the end of the Spring and Autumn period and the beginning of the Warring States period. The periodization dates to the late Western Han (). Background In 771 BCE, a Quanrong invasion in coalition with the states of Zeng (state), Zeng and Shen (state), Shen— ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Girl (Chinese Constellation)
The Girl mansion (女宿, pinyin: Nǚ Xiù) is one of the Twenty-eight mansions of the Chinese constellation Traditional Chinese astronomy has a system of dividing the celestial sphere into asterisms or constellations, known as "officials" ( Chinese ''xīng guān''). The Chinese asterisms are generally smaller than the constellations of Hellenisti ...s. It is one of the northern mansions of the Black Tortoise. Asterisms Notes {{Chinese constellation Chinese constellations ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chinese Astronomy
Astronomy in China has a long history stretching from the Shang dynasty, being refined over a period of more than 3,000 years. The Ancient China, ancient Chinese people have identified stars from 1300 BCE, as Chinese star names later categorized in the twenty-eight mansions have been found on oracle bones unearthed at Anyang, dating back to the mid-Shang dynasty. The core of the "mansion" (宿 ''xiù'') system also took shape around this period, by the time of King Wu Ding (1250–1192 BCE). Detailed records of astronomical observations began during the Warring States period (fourth century BCE). They flourished during the Han period (202 BCE – 220 CE) and subsequent dynasties with the publication of star catalogues. Chinese astronomy was equatorial, centered on close observation of circumpolar stars, and was based on different principles from those in traditional Western astronomy, where heliacal risings and settings of zodiac constellations formed the basic ecliptic framew ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apparent Magnitude
Apparent magnitude () is a measure of the Irradiance, brightness of a star, astronomical object or other celestial objects like artificial satellites. Its value depends on its intrinsic luminosity, its distance, and any extinction (astronomy), extinction of the object's light caused by interstellar dust along the sightline, line of sight to the observer. Unless stated otherwise, the word ''magnitude'' in astronomy usually refers to a celestial object's apparent magnitude. The magnitude scale likely dates to before the ancient Ancient Greek astronomy#Astronomy in the Greco-Roman and Late Antique eras, Roman astronomer Ptolemy, Claudius Ptolemy, whose Star catalogue, star catalog popularized the system by listing stars from First-magnitude star, 1st magnitude (brightest) to 6th magnitude (dimmest). The modern scale was mathematically defined to closely match this historical system by Norman Robert Pogson, Norman Pogson in 1856. The scale is reverse logarithmic scale, logarithmic: ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
A-type Main Sequence Star
An A-type main-sequence star (A) or A dwarf star is a main-sequence (hydrogen burning) star of spectral type A and luminosity class (five). These stars have spectra defined by strong hydrogen Balmer absorption lines. They measure between 1.7 and 2.1 solar masses (), have surface temperatures between 7,600 and 10,000 K, and live for about a quarter of the lifetime of our Sun. Bright and nearby examples are Altair (A7), Sirius A (A1), and Vega (A0). A-type stars do not have convective zones and thus are not expected to harbor magnetic dynamos. As a consequence, because they do not have strong stellar winds, they lack a means to generate X-ray emissions. Spectral standard stars The revised Yerkes Atlas system listed a dense grid of A-type dwarf spectral standard stars, but not all of these have survived to this day as standards. The "anchor points" and "dagger standards" of the MK spectral classification system among the A-type main-sequence dwarf stars, i.e. th ... [...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: * Elliptic orbit: * Parabolic trajectory: * Hyperbolic trajectory: The eccentricity is given by e = \sqrt where ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
