221 Eos
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221 Eos
221 Eos is a large main-belt asteroid that was discovered by Austrian astronomer Johann Palisa on January 18, 1882, in Vienna. In 1884, it was named after Eos, the Greek goddess of the dawn, to honour the opening of a new observatory that was hoped to bring about a new dawn for Viennese astronomy. The asteroid is orbiting the Sun with a semimajor axis of , a period of 5.22 years, and an eccentricity of 0.1. The orbital plane is inclined by 10.9° to the plane of the ecliptic. It has a mean cross-section of 104 km, and is spinning with a rotation period of 10.4 hours. Based upon its spectral characteristics, this object is classified as a K-type asteroid. The orbital properties show it to be a member of the extensive Eos asteroid family, which is named after it. The spectral properties of the asteroid suggest it may have come from a partially differentiated parent body. References External linksThe Asteroid Orbital Elements Database
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Lightcurve
In astronomy, a light curve is a graph (discrete mathematics), graph of the Radiance, light intensity of a celestial object or region as a function of time, typically with the magnitude (astronomy), magnitude of light received on the ''y''-axis and with time on the ''x''-axis. The light is usually in a particular frequency interval or frequency band, band. Light curves can be periodic, as in the case of eclipsing binary, eclipsing binaries, Cepheid variables, other periodic variables, and Methods of detecting extrasolar planets#Transit photometry, transiting extrasolar planets; or aperiodic, like the light curve of a nova, cataclysmic variable star, supernova, gravitational microlensing, microlensing event, or binary as observed during occultation events. The study of a light curve and other observations can yield considerable information about the physical process that produces such a light curve, or constrain the physical theories about it. Variable stars Graphs of the ap ...
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Observatory
An observatory is a location used for observing terrestrial, marine, or celestial events. Astronomy, climatology/meteorology, geophysics, oceanography and volcanology are examples of disciplines for which observatories have been constructed. The term ''observatoire'' has been used in French since at least 1976 to denote any institution that compiles and presents data on a particular subject (such as public health observatory) or for a particular geographic area (European Audiovisual Observatory). Astronomical observatories Astronomical observatories are mainly divided into four categories: space observatory, space-based, airborne observatory, airborne, ground-based, and underground-based. Historically, ground-based observatories were as simple as containing a mural instrument (for measuring the angle between stars) or Stonehenge (which has some alignments on astronomical phenomena). Ground-based observatories Ground-based observatories, located on the surface of Earth, are u ...
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S-type Asteroids (Tholen)
S-type (stony-type or silicaceous-type) asteroids are asteroids with a spectral type that is indicative of a siliceous (i.e. stony) mineralogical composition, hence the name. They have relatively high density. Approximately 17% of asteroids are of this type, making it the second-most common after the carbonaceous C-type. Characteristics S-type asteroids, with an astronomical albedo of typically 0.20, are moderately bright and consist mainly of iron- and magnesium-silicates. They are dominant in the inner part of the asteroid belt within 2.2 AU, common in the central belt within about 3 AU, but become rare farther out. The largest are 3 Juno (about 240–250 km across) and 15 Eunomia (230 km), with other large S-types being 29 Amphitrite, 532 Herculina and 7 Iris. These largest S-types are visible in 10x50 binoculars at most oppositions; the brightest, 7 Iris, can occasionally become brighter than +7.0, which is a higher magnitude than any asteroid ex ...
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Named Minor Planets
Named may refer to something that has been given a name. Named may also refer to: * named (computing), a widely used DNS server * Naming (parliamentary procedure) * The Named (band), an American industrial metal group In literature: * ''The Named'', a fantasy novel by Marianne Curley * The Named, a fictional race of prehistoric big cats, depicted in ''The Books of the Named'' series by Clare Bell See also * Name (other) * Names (other) Names are words or terms used for identification. Names may also refer to: * ''Names'' (EP), by Johnny Foreigner * ''Names'' (journal), an academic journal of onomastics * The Names (band), a Belgian post-punk band * ''The Names'' (novel), b ... * Naming (other) {{disambiguation ...
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Discoveries By Johann Palisa
Discoveries may refer to: Media Film and television * ''Discoveries'' (film), a 1939 British film * ''Discoveries'' (TV series), a Canadian youth science television series * "Discoveries", a Series D episode of the television series ''QI'' (2006) * "Discoveries" (''Hotel Portofino''), a 2022 TV episode Literature * ''Discoveries'' (Robertson Davies), a 2002 book by Robertson Davies * ''Abrams Discoveries'', a series of illustrated non-fiction books published by Harry N. Abrams * ''Discoveries'', a work by William Butler Yeats, written in 1907 * ''Discoveries'', a magazine published by Cedars-Sinai Medical Center Music * ''Discoveries'' (Cannonball Adderley album), 1955 * ''Discoveries'' (Josh Nelson album), 2011 * ''Discoveries'' (Northlane album), 2011 Other uses * Discoveries (horse), a racehorse See also * Age of Discoveries * Discovery (other) * Explorations (other) Exploration is the process of discovery. Exploration or explorations may ...
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Eos Asteroids
In ancient Greek mythology and religion, Eos (; Ionic and Homeric Greek ''Ēṓs'', Attic ''Héōs'', "dawn", or ; Aeolic ''Aúōs'', Doric ''Āṓs'') is the goddess and personification of the dawn, who rose each morning from her home at the edge of the river Oceanus to deliver light and disperse the night. In Greek tradition and poetry, she is characterized as a goddess with a great sexual appetite, who took numerous human lovers for her own satisfaction and bore them several children. Like her Roman counterpart Aurora and Rigvedic Ushas, Eos continues the name of an earlier Indo-European dawn goddess, Hausos. Eos, or her earlier Proto-Indo-European (PIE) ancestor, also shares several elements with the love goddess Aphrodite, perhaps signifying Eos's influence on her or otherwise a common origin for the two goddesses. In surviving tradition, Aphrodite is the culprit behind Eos' numerous love affairs, having cursed the goddess with insatiable lust for mortal men. In ...
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Planetary Differentiation
In planetary science, planetary differentiation is the process by which the chemical elements of a planetary body accumulate in different areas of that body, due to their physical or chemical behavior (e.g. density and chemical affinities). The process of planetary differentiation is mediated by partial melting with heat from radioactive isotope decay and planetary accretion. Planetary differentiation has occurred on planets, dwarf planets, the asteroid 4 Vesta, and natural satellites (such as the Moon). Physical differentiation Gravitational separation High- density materials tend to sink through lighter materials. This tendency is affected by the relative structural strengths, but such strength is reduced at temperatures where both materials are plastic or molten. Iron, the most common element that is likely to form a very dense molten metal phase, tends to congregate towards planetary interiors. With it, many siderophile elements (i.e. materials that readily alloy with iron ...
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Rotation Period
In astronomy, the rotation period or spin period of a celestial object (e.g., star, planet, moon, asteroid) has two definitions. The first one corresponds to the '' sidereal rotation period'' (or ''sidereal day''), i.e., the time that the object takes to complete a full rotation around its axis relative to the background stars ( inertial space). The other type of commonly used "rotation period" is the object's '' synodic rotation period'' (or ''solar day''), which may differ, by a fraction of a rotation or more than one rotation, to accommodate the portion of the object's orbital period around a star or another body during one day. Measuring rotation For solid objects, such as rocky planets and asteroids, the rotation period is a single value. For gaseous or fluid bodies, such as stars and giant planets, the period of rotation varies from the object's equator to its pole due to a phenomenon called differential rotation. Typically, the stated rotation period for a giant pl ...
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Plane Of The Ecliptic
The ecliptic or ecliptic plane is the orbital plane of Earth around the Sun. It was a central concept in a number of ancient sciences, providing the framework for key measurements in astronomy, astrology and calendar-making. From the perspective of an observer on Earth, the Sun's movement around the celestial sphere over the course of a year traces out a path along the ecliptic against the background of stars – specifically the Zodiac constellations. The planets of the Solar System can also be seen along the ecliptic, because their orbital planes are very close to Earth's. The Moon's orbital plane is also similar to Earth's; the ecliptic is so named because the ancients noted that eclipses only occur when the Moon is crossing it. The ecliptic is an important reference plane and is the basis of the ecliptic coordinate system. Ancient scientists were able to calculate Earth's axial tilt by comparing the ecliptic plane to that of the equator. Sun's apparent motion The ec ...
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Orbital Plane
The orbital plane of a revolving body is the geometric plane in which its orbit lies. Three non-collinear points in space suffice to determine an orbital plane. A common example would be the positions of the centers of a massive body (host) and of an orbiting celestial body at two different times/points of its orbit. The orbital plane is defined in relation to a reference plane by two parameters: inclination (''i'') and longitude of the ascending node (Ω). By definition, the reference plane for the Solar System is usually considered to be Earth's orbital plane, which defines the ecliptic, the circular path on the celestial sphere that the Sun appears to follow over the course of a year. In other cases, for instance a moon or artificial satellite orbiting another planet, it is convenient to define the inclination of the object's orbit as the angle between its orbital plane and the planet's equatorial plane. The coordinate system defined that uses the orbital plane as ...
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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 ...
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Orbital Period
The orbital period (also revolution period) is the amount of time a given astronomical object takes to complete one orbit around another object. In astronomy, it usually applies to planets or asteroids orbiting the Sun, moons orbiting planets, exoplanets orbiting other stars, or binary stars. It may also refer to the time it takes a satellite orbiting a planet or moon to complete one orbit. For celestial objects in general, the orbital period is determined by a 360° revolution of one body around its primary, ''e.g.'' Earth around the Sun. Periods in astronomy are expressed in units of time, usually hours, days, or years. Its reciprocal is the orbital frequency, a kind of revolution frequency, in units of hertz. Small body orbiting a central body According to Kepler's Third Law, the orbital period ''T'' of two point masses orbiting each other in a circular or elliptic orbit is: :T = 2\pi\sqrt where: * ''a'' is the orbit's semi-major axis * ''G'' is the gravitationa ...
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