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IM Lupi
IM Lupi is a young stellar object with a surrounding protoplanetary disk. The young star is suspected to host a still forming protoplanet at a distance of 110 astronomical units (AU) and a mass of 2-3 . IM Lupi is 508 light-years (156 parsec) distant. Star The star IM Lupi was classified as a class II YSO with a spectral type M0. The star is probably not actively accreting, but there is evidence that the accretion is variable around IM Lupi. The young star is associated with the Lupus 2 Molecular Cloud. Protoplanetary Disk Many features at different wavelengths have been observed in this disk, which is very massive (0.17 ). The disk has a gas and a dust component. The gas component reaches out to 751 AU and the smaller dust component reaches out to 334 AU. In a scattered light image from SPHERE the upper surface and part of the lower surface was imaged. Dust observations with ALMA shows two rings and with SPHERE 2 additional rings were detected. ALMA observations ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stellar Classification
In astronomy, stellar classification is the classification of stars based on their stellar spectrum, spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a Prism (optics), prism or diffraction grating into a spectrum exhibiting the Continuum (spectrum), rainbow of colors interspersed with spectral lines. Each line indicates a particular chemical element or molecule, with the line strength indicating the abundance of that element. The strengths of the different spectral lines vary mainly due to the temperature of the photosphere, although in some cases there are true abundance differences. The ''spectral class'' of a star is a short code primarily summarizing the ionization state, giving an objective measure of the photosphere's temperature. Most stars are currently classified under the Morgan–Keenan (MK) system using the letters ''O'', ''B'', ''A'', ''F'', ''G'', ''K'', and ''M'', a sequence from the hottest (''O'' type) to the cool ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protoplanets
A protoplanet is a large planetary embryo that originated within a protoplanetary disk and has undergone internal melting to produce a differentiated interior. Protoplanets are thought to form out of kilometer-sized planetesimals that gravitationally perturb each other's orbits and collide, gradually coalescing into the dominant planets. The planetesimal hypothesis A planetesimal is an object formed from dust, rock, and other materials, measuring from meters to hundreds of kilometers in size. According to the Chamberlin–Moulton planetesimal hypothesis and the theories of Viktor Safronov, a protoplanetary disk of materials such as gas and dust would orbit a star early in the formation of a planetary system. The action of gravity on such materials form larger and larger chunks until some reach the size of planetesimals. It is thought that the collisions of planetesimals created a few hundred larger planetary embryos. Over the course of hundreds of millions of years, they coll ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gravitational Instability
The key idea in explaining the way in which structures evolve in the universe is gravitational instability. If material is to be brought together to form structures, then a long-range force is required, and gravity is the only known possibility. (Although electromagnetism is a long-range force, charge neutrality demands that its influence is unimportant on large scales.) The basic picture is as follows. Suppose that at some initial time, say decoupling, there are small irregularities in the distribution of matter. Those regions with more matter will exert a greater gravitational force on their neighboring regions and hence tend to draw in the surrounding material. This extra material makes them even more dense than before, increasing their gravitational attraction and further enhancing their pull on their neighbors. An irregular distribution of matter is therefore unstable under the influence of gravity, becoming more and more irregular as time goes by. This instability is exac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exoplanet
An exoplanet or extrasolar planet is a planet outside the Solar System. The first confirmed detection of an exoplanet was in 1992 around a pulsar, and the first detection around a main-sequence star was in 1995. A different planet, first detected in 1988, was confirmed in 2003. In 2016, it was recognized that the first possible evidence of an exoplanet had been noted in 1917. In collaboration with ground-based and other space-based observatories the James Webb Space Telescope (JWST) is expected to give more insight into exoplanet traits, such as their composition, environmental conditions, and potential for life. There are many methods of detecting exoplanets. Transit photometry and Doppler spectroscopy have found the most, but these methods suffer from a clear observational bias favoring the detection of planets near the star; thus, 85% of the exoplanets detected are inside the tidal locking zone. In several cases, multiple planets have been observed around a star ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kepler Orbit
In celestial mechanics, a Kepler orbit (or Keplerian orbit, named after the German astronomer Johannes Kepler) is the motion of one body relative to another, as an ellipse, parabola, or hyperbola, which forms a two-dimensional orbital plane in three-dimensional space. A Kepler orbit can also form a straight line. It considers only the point-like gravitational attraction of two bodies, neglecting perturbations due to gravitational interactions with other objects, atmospheric drag, solar radiation pressure, a non- spherical central body, and so on. It is thus said to be a solution of a special case of the two-body problem, known as the Kepler problem. As a theory in classical mechanics, it also does not take into account the effects of general relativity. Keplerian orbits can be parametrized into six orbital elements in various ways. In most applications, there is a large central body, the center of mass of which is assumed to be the center of mass of the entire system. B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon Monoxide
Carbon monoxide (chemical formula CO) is a poisonous, flammable gas that is colorless, odorless, tasteless, and slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the simplest oxocarbon, carbon oxide. In coordination complexes, the carbon monoxide ligand is called ''metal carbonyl, carbonyl''. It is a key ingredient in many processes in industrial chemistry. The most common source of carbon monoxide is the partial combustion of carbon-containing compounds. Numerous environmental and biological sources generate carbon monoxide. In industry, carbon monoxide is important in the production of many compounds, including drugs, fragrances, and fuels. Indoors CO is one of the most acutely toxic contaminants affecting indoor air quality. CO may be emitted from tobacco smoke and generated from malfunctioning fuel-burning stoves (wood, kerosene, natural gas, propane) and fuel-burning heating systems (wood, oil, n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atacama Large Millimeter Array
The Atacama Large Millimeter/submillimeter Array (ALMA) is an astronomical interferometer of 66 radio telescopes in the Atacama Desert of northern Chile, which observe electromagnetic radiation at millimeter and submillimeter wavelengths. The array has been constructed on the elevation Chajnantor plateau – near the Llano de Chajnantor Observatory and the Atacama Pathfinder Experiment. This location was chosen for its high elevation and low humidity, factors which are crucial to reduce noise and decrease signal attenuation due to Earth's atmosphere. ALMA provides insight on star birth during the early Stelliferous era and detailed imaging of local star and planet formation. ALMA is an international partnership amongst Europe, the United States, Canada, Japan, South Korea, Taiwan, and Chile. Costing about US$1.4 billion, it is the most expensive ground-based telescope in operation. ALMA began scientific observations in the second half of 2011 and the first images were rel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spectro-Polarimetric High-Contrast Exoplanet Research
Spectro-Polarimetric High-contrast Exoplanet REsearch (VLT-SPHERE) is an adaptive optics system and coronagraphic facility at the Very Large Telescope (VLT). It provides direct imaging as well as spectroscopic and polarimetric characterization of exoplanet systems. The instrument operates in the visible and near infrared, achieving exquisite image quality and contrast over a small field of view around bright targets. Results from SPHERE complement those from other planet finder projects, which include HARPS, CoRoT, and the Kepler Mission. The instrument was installed on Unit Telescope "Melipal" (UT3) and achieved First light (astronomy), first light in May, 2014. At the time of installation, it was the latest of a series of second generation VLT-instruments such as Very Large Telescope#Instruments, X-shooter, K-band Multi-Object Spectrograph, KMOS and Multi Unit Spectroscopic Explorer, MUSE. Science goals Direct imaging of exoplanets is extremely challenging: # The brightnes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Young Stellar Object
Young stellar object (YSO) denotes a star in its early stage of evolution. This class consists of two groups of objects: protostars and pre-main-sequence stars. Classification by spectral energy distribution A star forms by accumulation of material that falls in to a protostar from a circumstellar disk or envelope. Material in the disk is cooler than the surface of the protostar, so it radiates at longer wavelengths of light producing excess infrared emission. As material in the disk is depleted, the infrared excess decreases. Thus, YSOs are usually classified into evolutionary stages based on the slope of their spectral energy distribution in the mid-infrared, using a scheme introduced by Lada (1987). He proposed three classes (I, II and III), based on the values of intervals of spectral index \alpha \,: \alpha=\frac. Here \lambda \, is wavelength, and F_\lambda is flux density. The \alpha \, is calculated in the wavelength interval of 2.2–20 m ( near- and mid-infrared r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lupus (constellation)
Lupus is a constellation of the mid-Southern Sky. Its name is Latin for wolf. Lupus was one of the 48 constellations listed by the 2nd-century astronomer Ptolemy, and it remains one of the IAU designated constellations, 88 modern constellations but was long an Asterism (astronomy), asterism associated with the just westerly, larger constellation Centaurus. History and mythology In ancient times, the constellation was considered an Asterism (astronomy), asterism within Centaurus, and was considered to have been an arbitrary animal, killed, or about to be killed, on behalf of, or for, Centaurus. An alternative visualization, attested by Eratosthenes, saw this constellation as a wineskin held by Centaurus. It was not separated from Centaurus until Hipparchus, Hipparchus of Bithynia named it ( meaning "beast") in the 2nd century BC. The Greek constellation is probably based on the Babylonian figure known as the Uridimmu, Mad Dog (UR.IDIM). This was a strange hybrid creature that c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parsec
The parsec (symbol: pc) is a unit of length used to measure the large distances to astronomical objects outside the Solar System, approximately equal to or (AU), i.e. . The parsec unit is obtained by the use of parallax and trigonometry, and is defined as the distance at which 1 AU subtended angle, subtends an angle of one arcsecond ( of a degree (angle), degree). The nearest star, Proxima Centauri, is about from the Sun: from that distance, the gap between the Earth and the Sun spans slightly less than one arcsecond. Most Naked-eye stars, stars visible to the naked eye are within a few hundred parsecs of the Sun, with the most distant at a few thousand parsecs, and the Andromeda Galaxy at over 700,000 parsecs. The word ''parsec'' is a shortened form of ''a distance corresponding to a parallax of one second'', coined by the British astronomer Herbert Hall Turner in 1913. The unit was introduced to simplify the calculation of astronomical distances from raw observational data. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
