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HD 137388 B
HD 137388 is an orange-hued star in the southern constellation of Apus. It has the proper name Karaka, after the native New Zealand karaka tree. The name was assigned by representatives of New Zealand in the IAU's NameExoWorlds contest. The star is too faint to be visible to the naked eye, having an apparent visual magnitude of 8.70. It is located at a distance of 132 light years from the Sun based on parallax. The star is drifting further away with a radial velocity of +26 km/s, having come as close as some 1.2 million years ago. It has an absolute magnitude of 5.75. The stellar classification of HD 137388 is K2IV, matching that of an evolving subgiant star. However, in 2011 Dumusque and colleagues found a class of K0/K1V, suggesting it is instead a K-type main-sequence star. It is around three billion years old and is spinning with a projected rotational velocity of 2.2 km/s. The star shows a magnetic activity cycle, similar to the solar cycle. It ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apus (constellation)
Apus is a small constellation in the southern sky. It represents a bird-of-paradise, and its name means "without feet" in Greek because the bird-of-paradise was once wrongly believed to lack feet. First depicted on a celestial globe by Petrus Plancius in 1598, it was charted on a star atlas by Johann Bayer in his 1603 ''Uranometria''. The French explorer and astronomer Nicolas Louis de Lacaille charted and gave the brighter stars their Bayer designations in 1756. The five brightest stars are all reddish in hue. Shading the others at apparent magnitude 3.8 is Alpha Apodis, an orange giant that has around 48 times the diameter and 928 times the luminosity of the Sun. Marginally fainter is Gamma Apodis, another ageing giant star. Delta Apodis is a double star, the two components of which are 103 arcseconds apart and visible with the naked eye. Two star systems have been found to have planets. History Apus was one of twelve constellations published by Petrus Plancius from the o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromospheric Activity
A chromosphere ("sphere of color") is the second layer of a star's atmosphere, located above the photosphere and below the solar transition region and corona. The term usually refers to the Sun's chromosphere, but not exclusively. In the Sun's atmosphere, the chromosphere is roughly in height, or slightly more than 1% of the Sun's radius at maximum thickness. It possesses a homogeneous layer at the boundary with the photosphere. Hair-like jets of plasma, called spicules, rise from this homogeneous region and through the chromosphere, extending up to into the corona above. The chromosphere has a characteristic red color due to electromagnetic emissions in the ''H''α spectral line. Information about the chromosphere is primarily obtained by analysis of its emitted electromagnetic radiation. Chromospheres have also been observed on stars other than the Sun. On large stars, chromospheres sometimes make up a significant proportion of the entire star. For example, the c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
K-type Subgiants , 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] |
HD 137388 B
HD 137388 is an orange-hued star in the southern constellation of Apus. It has the proper name Karaka, after the native New Zealand karaka tree. The name was assigned by representatives of New Zealand in the IAU's NameExoWorlds contest. The star is too faint to be visible to the naked eye, having an apparent visual magnitude of 8.70. It is located at a distance of 132 light years from the Sun based on parallax. The star is drifting further away with a radial velocity of +26 km/s, having come as close as some 1.2 million years ago. It has an absolute magnitude of 5.75. The stellar classification of HD 137388 is K2IV, matching that of an evolving subgiant star. However, in 2011 Dumusque and colleagues found a class of K0/K1V, suggesting it is instead a K-type main-sequence star. It is around three billion years old and is spinning with a projected rotational velocity of 2.2 km/s. The star shows a magnetic activity cycle, similar to the solar cycle. It ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New Zealand Pigeon
New is an adjective referring to something recently made, discovered, or created. New or NEW may refer to: Music * New, singer of K-pop group The Boyz Albums and EPs * ''New'' (album), by Paul McCartney, 2013 * ''New'' (EP), by Regurgitator, 1995 Songs * "New" (Daya song), 2017 * "New" (Paul McCartney song), 2013 * "New" (No Doubt song), 1999 *"new", by Loona from '' Yves'', 2017 *"The New", by Interpol from ''Turn On the Bright Lights'', 2002 Acronyms * Net economic welfare, a proposed macroeconomic indicator * Net explosive weight, also known as net explosive quantity * Network of enlightened Women, a conservative university women's organization * Next Entertainment World, a South Korean film distribution company Identification codes * Nepal Bhasa language ISO 639 language code * New Century Financial Corporation (NYSE stock abbreviation) * Northeast Wrestling, a professional wrestling promotion in the northeastern United States Transport * New Orleans Lakefront Ai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Māori Language
Māori (), or ('the Māori language'), also known as ('the language'), is an Eastern Polynesian language spoken by the Māori people, the indigenous population of mainland New Zealand. Closely related to Cook Islands Māori, Tuamotuan, and Tahitian, it gained recognition as one of New Zealand's official languages in 1987. The number of speakers of the language has declined sharply since 1945, but a Māori-language revitalisation effort has slowed the decline. The 2018 New Zealand census reported that about 186,000 people, or 4.0% of the New Zealand population, could hold a conversation in Māori about everyday things. , 55% of Māori adults reported some knowledge of the language; of these, 64% use Māori at home and around 50,000 people can speak the language "very well" or "well". The Māori language did not have an indigenous writing system. Missionaries arriving from about 1814, such as Thomas Kendall, learned to speak Māori, and introduced the Latin alphabet. In 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Habitable Zone
In astronomy and astrobiology, the circumstellar habitable zone (CHZ), or simply the habitable zone, is the range of orbits around a star within which a planetary surface can support liquid water given sufficient atmospheric pressure.J. F. Kasting, D. P. Whitmire, R. T. Reynolds, Icarus 101, 108 (1993). The bounds of the CHZ are based on Earth's position in the Solar System and the amount of radiant energy it receives from the Sun. Due to the importance of liquid water to Earth's biosphere, the nature of the CHZ and the objects within it may be instrumental in determining the scope and distribution of planets capable of supporting Earth-like extraterrestrial life and intelligence. The habitable zone is also called the Goldilocks zone, a metaphor, allusion and antonomasia of the children's fairy tale of "Goldilocks and the Three Bears", in which a little girl chooses from sets of three items, ignoring the ones that are too extreme (large or small, hot or cold, etc.), and settl ... [...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] |
Photosphere
The photosphere is a star's outer shell from which light is radiated. The term itself is derived from Ancient Greek roots, φῶς, φωτός/''phos, photos'' meaning "light" and σφαῖρα/''sphaira'' meaning "sphere", in reference to it being a spherical surface that is perceived to emit light. It extends into a star's surface until the plasma becomes opaque, equivalent to an optical depth of approximately , or equivalently, a depth from which 50% of light will escape without being scattered. A photosphere is the deepest region of a luminous object, usually a star, that is transparent to photons of certain wavelengths. Temperature The surface of a star is defined to have a temperature given by the effective temperature in the Stefan–Boltzmann law. Stars, except neutron stars, have no solid or liquid surface. Therefore, the photosphere is typically used to describe the Sun's or another star's visual surface. Composition of the Sun The Sun is composed primarily of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Luminosity Of The Sun
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] |
Metallicity
In astronomy, metallicity is the abundance of elements present in an object that are heavier than hydrogen and helium. Most of the normal physical matter in the Universe is either hydrogen or helium, and astronomers use the word ''"metals"'' as a convenient short term for ''"all elements except hydrogen and helium"''. This word-use is distinct from the conventional chemical or physical definition of a metal as an electrically conducting solid. Stars and nebulae with relatively high abundances of heavier elements are called "metal-rich" in astrophysical terms, even though many of those elements are nonmetals in chemistry. The presence of heavier elements hails from stellar nucleosynthesis, where the majority of elements heavier than hydrogen and helium in the Universe (''metals'', hereafter) are formed in the cores of stars as they evolve. Over time, stellar winds and supernovae deposit the metals into the surrounding environment, enriching the interstellar medium and providing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stellar Spectrum
Astronomical spectroscopy is the study of astronomy using the techniques of spectroscopy to measure the spectrum of electromagnetic radiation, including visible light, ultraviolet, X-ray, infrared and radio waves that radiate from stars and other celestial objects. A stellar spectrum can reveal many properties of stars, such as their chemical composition, temperature, density, mass, distance and luminosity. Spectroscopy can show the velocity of motion towards or away from the observer by measuring the Doppler shift. Spectroscopy is also used to study the physical properties of many other types of celestial objects such as planets, nebulae, galaxies, and active galactic nuclei. Background Astronomical spectroscopy is used to measure three major bands of radiation in the electromagnetic spectrum: visible light, radio waves, and X-rays. While all spectroscopy looks at specific bands of the spectrum, different methods are required to acquire the signal depending on the frequency. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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