|
HD 111232
HD 111232 is a star in the southern constellation of Musca. It is too faint to be visible with the naked eye, having an apparent visual magnitude of 7.59. The distance to this star is 94.5 light years based on parallax. It is drifting away from the Sun with a radial velocity of +104 km/s, having come to within some 264,700 years ago. The absolute magnitude of this star is 5.25, indicating it would have been visible to the naked eye at that time. This is an ancient, thick disk population II star with an estimated age of twelve billion years. It is a G-type main-sequence star with a stellar classification of G8 V Fe-1.0, indicating an anomalous underabundance of iron in the stellar atmosphere. The star has 80% of the mass of the Sun and 88% of the Sun's radius. It is spinning slowly with a projected rotational velocity of 0.4 km/s. X-ray emission has not been detected, suggesting a low level of coronal activity. The star is radiating 70% of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Musca
Musca () is a small constellation in the deep southern sky. It was one of 12 constellations created by Petrus Plancius from the observations of Pieter Dirkszoon Keyser and Frederick de Houtman, and it first appeared on a celestial globe in diameter published in 1597 (or 1598) in Amsterdam by Plancius and Jodocus Hondius. The first depiction of this constellation in a celestial atlas was in Johann Bayer's '' Uranometria'' of 1603. It was also known as Apis () for 200 years. Musca remains below the horizon for most Northern Hemisphere observers. Many of the constellation's brighter stars are members of the Scorpius–Centaurus association, a loose group of hot blue-white stars that appears to share a common origin and motion across the Milky Way. These include Alpha, Beta, Gamma, Zeta2 and (probably) Eta Muscae, as well as HD 100546, a blue-white Herbig Ae/Be star that is surrounded by a complex debris disk containing a large planet or brown dwarf and possible prot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Activity
A stellar magnetic field is a magnetic field generated by the motion of conductive plasma inside a star. This motion is created through convection, which is a form of energy transport involving the physical movement of material. A localized magnetic field exerts a force on the plasma, effectively increasing the pressure without a comparable gain in density. As a result, the magnetized region rises relative to the remainder of the plasma, until it reaches the star's photosphere. This creates starspots on the surface, and the related phenomenon of coronal loops. Measurement The magnetic field of a star can be measured by means of the Zeeman effect. Normally the atoms in a star's atmosphere will absorb certain frequencies of energy in the electromagnetic spectrum, producing characteristic dark absorption lines in the spectrum. When the atoms are within a magnetic field, however, these lines become split into multiple, closely spaced lines. The energy also becomes polarized with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
G-type Main-sequence Stars
A G-type main-sequence star (Spectral type: G-V), also often, and imprecisely called a yellow dwarf, or G star, is a main-sequence star (luminosity class V) of spectral type G. Such a star has about 0.9 to 1.1 solar masses and an effective temperature between about 5,300 and 6,000 K. Like other main-sequence stars, a G-type main-sequence star is converting the element hydrogen to helium in its core by means of nuclear fusion, but can also fuse helium when hydrogen runs out. The Sun, the star in the center of the Solar System to which the Earth is gravitationally bound, is an example of a G-type main-sequence star (G2V type). Each second, the Sun fuses approximately 600 million tons of hydrogen into helium in a process known as the proton–proton chain (4 hydrogens form 1 helium), converting about 4 million tons of matter to energy. Besides the Sun, other well-known examples of G-type main-sequence stars include Alpha Centauri, Tau Ceti, Capella and 51 Pegasi. The term ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Astrophysical Journal Supplement Series
''The Astrophysical Journal'', often abbreviated ''ApJ'' (pronounced "ap jay") in references and speech, is a peer-reviewed scientific journal of astrophysics and astronomy, established in 1895 by American astronomers George Ellery Hale and James Edward Keeler. The journal discontinued its print edition and became an electronic-only journal in 2015. Since 1953 ''The Astrophysical Journal Supplement Series'' (''ApJS'') has been published in conjunction with ''The Astrophysical Journal'', with generally longer articles to supplement the material in the journal. It publishes six volumes per year, with two 280-page issues per volume. ''The Astrophysical Journal Letters'' (''ApJL''), established in 1967 by Subrahmanyan Chandrasekhar as Part 2 of ''The Astrophysical Journal'', is now a separate journal focusing on the rapid publication of high-impact astronomical research. The three journals were published by the University of Chicago Press for the American Astronomical Society u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HD 111232 B
HD 111232 b is an extrasolar planet that orbits at almost 2 AU with a minimum mass of 6.8 times that of Jupiter. This planet was discovered in the La Silla Observatory by Michel Mayor using the CORALIE spectrograph on 30 June 2003, along with six other planets, including HD 41004 Ab, HD 65216 b, HD 169830 c, HD 216770 b, HD 10647 b, and HD 142415 b. An astrometric measurement of the planet's inclination and true mass was published in 2022 as part of Gaia DR3 The ''Gaia'' catalogues are star catalogues created using the results obtained by '' Gaia'' space telescope. The catalogues are released in stages that will contain increasing amounts of information; the early releases also miss some stars, espec .... References External links * Exoplanets discovered in 2003 Giant planets Musca (constellation) Exoplanets detected by radial velocity Exoplanets detected by astrometry {{extrasolar-planet-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brown Dwarf
Brown dwarfs (also called failed stars) are substellar objects that are not massive enough to sustain nuclear fusion of ordinary hydrogen (hydrogen-1, 1H) into helium in their cores, unlike a main sequence, main-sequence star. Instead, they have a mass between the most massive gas giant planets and the least massive stars, approximately 13 to 80 Jupiter mass, times that of Jupiter (). However, they can deuterium burning, fuse deuterium (deuterium, 2H), and the most massive ones (> ) can lithium burning, fuse lithium (lithium-7, 7Li). Astronomers classify self-luminous objects by spectral classification, spectral class, a distinction intimately tied to the surface temperature, and brown dwarfs occupy types M, L, T, and Y. As brown dwarfs do not undergo stable hydrogen fusion, they cool down over time, progressively passing through later spectral types as they age. Despite their name, to the naked eye, brown dwarfs would appear in different colors depending on their temperatur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gaia DR3
The ''Gaia'' catalogues are star catalogues created using the results obtained by ''Gaia'' space telescope. The catalogues are released in stages that will contain increasing amounts of information; the early releases also miss some stars, especially fainter stars located in dense star fields. Data from every data release can be accessed at the ''Gaia'' archive. Initial Gaia Source List The Initial Gaia Source List (IGSL) is a star catalogue of 1.2 billion objects created in support of the ''Gaia'' mission. The mission should have delivered a catalogue based entirely on its own data. For the first catalogue, Gaia DR1, a way was needed to be able to assign the observations to an object and to compare them with the objects from other star catalogues. For this purpose, a separate catalog of objects from several other catalogues was compiled, which roughly represents the state of knowledge of astronomy at the beginning of the Gaia mission. Attitude Star Catalog The Attitude Star ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astrometry
Astrometry is a branch of astronomy that involves precise measurements of the positions and movements of stars and other celestial bodies. It provides the kinematics and physical origin of the Solar System and this galaxy, the Milky Way. History The history of astrometry is linked to the history of star catalogues, which gave astronomers reference points for objects in the sky so they could track their movements. This can be dated back to Hipparchus, who around 190 BC used the catalogue of his predecessors Timocharis and Aristillus to discover Earth's precession. In doing so, he also developed the brightness scale still in use today. Hipparchus compiled a catalogue with at least 850 stars and their positions. Hipparchus's successor, Ptolemy, included a catalogue of 1,022 stars in his work the ''Almagest'', giving their location, coordinates, and brightness. In the 10th century, Abd al-Rahman al-Sufi carried out observations on the stars and described their positions, magn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HD 181720
HD 181720 is star with an orbiting substellar companion in the southern constellation of Sagittarius. It is located at a distance of 196 light years from the Sun based on parallax measurements, but is drifting closer with a radial velocity of −45.4 km/s. The star has an absolute magnitude of 4.10, but at that distance it has an apparent visual magnitude of 7.84, which is too faint to be seen with the naked eye. It shows a high proper motion, traversing the celestial sphere at an angular rate of . The spectrum of HD 181720 presents as an ordinary G-type main-sequence star with a stellar classification of G1V. It is an older star with an estimated age of roughly 12 billion years and a minimal level of magnetic activity in its chromosphere. The star has 87% of the mass of the Sun but the radius is now 42% larger than the Sun's. Its metallicity content, as measured by the abundance of iron, is three-tenths as much as in the Sun. HD 181720 is radiating more th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HD 22781
HD 22781, is a single star about away. It is a K-type main-sequence star. The star’s age is poorly constrained at billion years, but is likely similar to that of the Sun. HD 22781 is heavily depleted in heavy elements, having just 45% of Sun's concentration of iron, yet is comparatively rich in carbon, having 90% of Sun`s abundance. An imaging survey in 2012 has failed to find any stellar companions, suggesting HD 22781 is a single star. Planetary system In 2011 a transiting superjovian planet or brown dwarf b was detected on an extremely eccentric orbit. It is located just outside of the conservative habitable zone of the parent star. Planets around such metal-poor stars are rare; the only three known similar cases are HD 111232 and HD 181720 HD 181720 is star with an orbiting substellar companion in the southern constellation of Sagittarius. It is located at a distance of 196 light years from the Sun based on parallax measurements, but is drift ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CORALIE
Coralie is a French feminine name meaning "coral", derived from the Latin word ''coralium''.Also spelt ''corallum'', ''corallium'' or ''curalium'', cf.br>Whitaker's Words/ref> It was the eighth most popular name for baby girls in Quebec in 2007. Notable people with the name Coralie include: * Coralie Balmy * Coralie Clément * Coralie Dubost * Coralie Simmons * Coralie Frasse Sombet * Coralie Trinh Thi * Coralie Winn, urban arts director Other uses * Coralie, the French-built second stage of ELDO's Europa rocket * Coralie, Queensland, a locality in the Shire of Croydon, Australia * CORALIE spectrograph * Coralia Accor S.A. is a French multinational hospitality company that owns, manages and franchises hotels, resorts and vacation properties. It is the largest hospitality company in Europe, and the sixth largest hospitality company worldwide. Accor ope ... References {{given name French feminine given names ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Super-Jupiter
A super-Jupiter is a gas giant exoplanet that is more massive than the planet Jupiter. For example, companions at the planet–brown dwarf borderline have been called super-Jupiters, such as around the star Kappa Andromedae. By 2011 there were 180 known super-Jupiters, some hot, some cold. Even though they are more massive than Jupiter, they remain about the same size as Jupiter up to 80 Jupiter masses. This means that their surface gravity and density go up proportionally to their mass. The increased mass compresses the planet due to gravity, thus keeping it from being larger. In comparison, planets somewhat lighter than Jupiter can be larger, so-called " puffy planets" (gas giants with a large diameter but low density). An example of this may be the exoplanet HAT-P-1b with about half the mass of Jupiter but about 1.38 times larger diameter. CoRoT-3b, with a mass around 22 Jupiter masses, is predicted to have an average density of 26.4 g/cm3, greater than osmium (22.6 g/cm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
