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Jupiter Analogue
Jupiter analogues, also known as Jupiter-like planets, are exoplanets that are similar to the planet Jupiter, the fifth and largest planet in the Solar System, solar system. They are often defined as planets that has at least 1 Jupiter mass or larger and orbits its host star at a distance 3 to 12 astronomical units (AU), roughly one to a few times that of the systems Frost line (astrophysics), snow line. The lower limit of mass for Jupiter-like planets is not well defined as it can be as low of 0.8-0.3 Jupiter masses to include planets like Saturn. Formation and evolution While the exact formation of Jupiter-like exoplanets are not known, models of gas giant planet formation predict that Jupiter-like planets should easily form around stars similar to our Sun through Core-accretion theory, core-accretion mechanisms. This therefore should make planets similar to Jupiter a common occurrence in the universe with roughly 6-20% of Sun-like stars having Jupiter-like planets. But this ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Portrait Of Jupiter From Cassini
A portrait is a portrait painting, painting, portrait photography, photograph, sculpture, or other artistic representation of a person, in which the face is always predominant. In arts, a portrait may be represented as half body and even full body. If the subject in full body better represents personality and mood, this type of presentation may be chosen. The intent is to display the likeness, Personality type, personality, and even the mood of the person. For this reason, in photography a portrait is generally not a Snapshot (photography), snapshot, but a composed image of a person in a still position. A portrait often shows a person looking directly at the painter or photographer, to most successfully engage the subject with the viewer, but portrait may be represented as a profile (from aside) and 3/4. History Prehistorical portraiture Plastered human skulls were reconstructed human skulls that were made in the ancient Levant between 9000 and 6000 BC in the Pre-Pottery Ne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Universe
The universe is all of space and time and their contents. It comprises all of existence, any fundamental interaction, physical process and physical constant, and therefore all forms of matter and energy, and the structures they form, from sub-atomic particles to entire Galaxy filament, galactic filaments. Since the early 20th century, the field of cosmology establishes that space and time emerged together at the Big Bang ago and that the Expansion of the universe, universe has been expanding since then. The observable universe, portion of the universe that can be seen by humans is approximately 93 billion light-years in diameter at present, but the total size of the universe is not known. Some of the earliest Timeline of cosmological theories, cosmological models of the universe were developed by ancient Greek philosophy, ancient Greek and Indian philosophy, Indian philosophers and were geocentric model, geocentric, placing Earth at the center. Over the centuries, more prec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
51 Eridani
51 Eridani is a star in the constellation Eridanus. It has an apparent magnitude of 5.22, meaning it is just visible to the unaided eye in suburban and rural skies. The primary star's absolute magnitude is 2.87. There is also a binary star named GJ 3305 which shares the same proper motion through space with it, making it overall a triple star system. General information Johann Bayer gave the star its Bayer designation of c Eridani, using lowercase letters once he had exhausted all the letters of the Greek alphabet, in his 1603 star chart ''Uranometria''. It was catalogued as 51 Eridani by John Flamsteed in 1725. Located around 97 light-years distant, it shines with a luminosity approximately 5.72 times that of the Sun and has a surface temperature of . A cold debris disk has been detected with a likely inner border of 82 astronomical units (AU). A yellow-white main-sequence star of spectral type F0V, 51 Eridani is a member of the Beta Pictoris moving group and hence t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
F-type Main-sequence Star
An F-type main-sequence star (F V) is a main-sequence, hydrogen-fusing star of spectral type F and luminosity class V. These stars have from 1.0 to 1.4 times the mass of the Sun and surface temperatures between 6,000 and 7,600 K.Tables VII and VIII. This temperature range gives the F-type stars a whitish hue when observed by the atmosphere. Because a main-sequence star is referred to as a dwarf star, this class of star may also be termed a yellow-white dwarf (not to be confused with white dwarfs, remnant stars that are a possible final stage of stellar evolution). Notable examples include Procyon A, Gamma Virginis A and B, and KIC 8462852. Spectral standard stars The revised Yerkes Atlas system (Johnson & Morgan 1953) listed a dense grid of F-type dwarf spectral standard stars; however, not all of these have survived to this day as stable standards. The ''anchor points'' of the MK spectral classification system among the F-type main-sequence dwarf stars, i.e. thos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kepler-167
Kepler-167 is a K-type main-sequence star located about away from the Solar System in the constellation of Cygnus. The star has about 78% the mass and 75% the radius of the Sun, and a temperature of . It hosts a system of four known exoplanets. There is also a companion red dwarf star at a separation of about , with an estimated orbital period of over 15,000 years. Planetary system Kepler-167 is orbited by four known transiting exoplanets, discovered using the Kepler space telescope. The inner three planets are all super-Earths of unknown composition orbiting closer to their star than Mercury is to the Sun. The outermost planet, Kepler-167e, is a Jupiter analog, with , , and an equilibrium temperature of . It is the first transiting Jupiter analog discovered. The inner two planets were confirmed in 2014, as part of a study validating hundreds of Kepler planets, and the outer two planets were confirmed in 2016. Observations of Kepler-167e using the Spitzer Space Tele ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
K-type Main-sequence Star
A K-type main-sequence star, also referred to as a K-type dwarf, or orange dwarf, is a main-sequence (hydrogen-burning) star of spectral type K and luminosity class V. These stars are intermediate in size between red M-type main-sequence stars ("red dwarfs") and yellow/white G-type main-sequence stars. They have masses between 0.6 and 0.9 times the mass of the Sun and surface temperatures between 3,900 and 5,300 K. These stars are of particular interest in the search for extraterrestrial life due to their stability and long lifespan. These stars stay on the main sequence for up to 70 billion years, a length of time much larger than the time the universe has existed (13.8 billion years), as such none have had sufficient time to leave the main sequence. Well-known examples include Alpha Centauri B (K1 V), Epsilon Indi (K5 V) and Epsilon Eridani (K2 V). Nomenclature In modern usage, the names applied to K-type main sequence stars vary. When explicitly defined, late K dwarf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Formation And Evolution Of The Solar System
There is evidence that the formation of the Solar System began about 4.6 billion years ago with the gravitational collapse of a small part of a giant molecular cloud. Most of the collapsing mass collected in the center, forming the Sun, while the rest flattened into a protoplanetary disk out of which the planets, moons, asteroids, and other small Solar System bodies formed. This model, known as the nebular hypothesis, was first developed in the 18th century by Emanuel Swedenborg, Immanuel Kant, and Pierre-Simon Laplace. Its subsequent development has interwoven a variety of scientific disciplines including astronomy, chemistry, geology, physics, and planetary science. Since the dawn of the Space Age in the 1950s and the discovery of exoplanets in the 1990s, the model has been both challenged and refined to account for new observations. The Solar System has evolved considerably since its initial formation. Many moons have formed from circling discs of gas and dust around thei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Red Dwarf
A red dwarf is the smallest kind of star on the main sequence. Red dwarfs are by far the most common type of fusing star in the Milky Way, at least in the neighborhood of the Sun. However, due to their low luminosity, individual red dwarfs are not easily observed. Not one star that fits the stricter definitions of a red dwarf is visible to the naked eye. Proxima Centauri, the star nearest to the Sun, is a red dwarf, as are fifty of the sixty nearest stars. According to some estimates, red dwarfs make up three-quarters of the fusing stars in the Milky Way. The coolest red dwarfs near the Sun have a surface temperature of about and the smallest have radii about 9% that of the Sun, with masses about 7.5% that of the Sun. These red dwarfs have spectral types of L0 to L2. There is some overlap with the properties of brown dwarfs, since the most massive brown dwarfs at lower metallicity can be as hot as and have late M spectral types. Definitions and usage of the term "red d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Core-accretion Theory
The nebular hypothesis is the most widely accepted model in the field of cosmogony to explain the formation and evolution of the Solar System (as well as other planetary systems). It suggests the Solar System is formed from gas and dust orbiting the Sun which clumped up together to form the planets. The theory was developed by Immanuel Kant and published in his ''Universal Natural History and Theory of the Heavens'' (1755) and then modified in 1796 by Pierre Laplace. Originally applied to the Solar System, the process of planetary system formation is now thought to be at work throughout the universe. The widely accepted modern variant of the nebular theory is the solar nebular disk model (SNDM) or solar nebular model. It offered explanations for a variety of properties of the Solar System, including the nearly circular and coplanar orbits of the planets, and their motion in the same direction as the Sun's rotation. Some elements of the original nebular theory are echoed in modern th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
