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HD 142022
HD 142022 is a binary star system located in the southernmost constellation of Octans. It is too faint to be visible to the naked eye, having an apparent visual magnitude of 7.70. The distance to this system is based on stellar parallax, parallax, but it is drifting closer to the Sun with a radial velocity of −10 km/s. The primary, designated component A, is an old, Population I G-type star with a stellar classification of G9IV-V, showing a stellar spectrum, spectrum with mixed traits of a main sequence and a subgiant star. It is an estimated 7.6 billion years old and is spinning with a projected rotational velocity of 2 km/s. The star has similar mass and dimensions as the Sun, but has a 55% higher metallicity. It is radiating 89% of the luminosity of the Sun from its photosphere at an effective temperature of 5516 K. The magnitude 11.19 companion has the designation LTT 6384 and appears gravitationally bound to the primary. The pair have an angular ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Octans
Octans is a faint constellation located in the deep southern celestial hemisphere, Southern Sky. Its name is Latin for the eighth part of a circle, but it is named after the octant (instrument), octant, a navigational instrument. Devised by kingdom of France, French astronomer Nicolas Louis de Lacaille in 1752, Octans remains one of the IAU designated constellations, 88 modern constellations. The southern celestial pole is located within the boundaries of Octans. History and mythology Octans was one of 14 constellations created by French astronomer Nicolas Louis de Lacaille during his expedition to the Cape of Good Hope, and was originally named ''l’Octans de Reflexion'' (“the reflecting octant”) in 1752, after he had observed and catalogued almost 10,000 southern stars during a two-year stay at the Cape of Good Hope. He devised fourteen new constellations in uncharted regions of the Southern Celestial Hemisphere not visible from Europe. All but one honoured instruments that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angular Separation
Angular distance or angular separation is the measure of the angle between the orientation of two straight lines, rays, or vectors in three-dimensional space, or the central angle subtended by the radii through two points on a sphere. When the rays are lines of sight from an observer to two points in space, it is known as the apparent distance or apparent separation. Angular distance appears in mathematics (in particular geometry and trigonometry) and all natural sciences (e.g., kinematics, astronomy, and geophysics). In the classical mechanics of rotating objects, it appears alongside angular velocity, angular acceleration, angular momentum, moment of inertia and torque. Use The term ''angular distance'' (or ''separation'') is technically synonymous with ''angle'' itself, but is meant to suggest the linear distance between objects (for instance, a pair of stars observed from Earth). Measurement Since the angular distance (or separation) is conceptually identical to an ang ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
M-type Main-sequence Stars
Type M or M type may refer to: Science and technology * Type M, a xD-Picture Card * Type M, a name for the 15 amp BS 546 electrical plug * Vaio Type M, a kind of Vaio computer from Sony * M-type asteroid * m-type filter, an electronic filter * M-type star * M-types, an implementation of inductive type In type theory, a system has inductive types if it has facilities for creating a new type from constants and functions that create terms of that type. The feature serves a role similar to data structures in a programming language and allows a ty ... Other uses * Audi Type M, a 1920s car * Beretta 92FS Compact Type M, a pistol * MG M-type, a sports car See also * M class (other) * Class M (other) {{disambiguation ... [...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, main-sequence star (luminosity class V) of stellar classification, spectral type G. Such a star has about 0.9 to 1.1 solar masses and an effective temperature between about . Like other main-sequence stars, a G-type main-sequence star converts the Chemical element, element hydrogen to helium in its core by means of nuclear fusion. 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), Mass–energy equivalence, 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, and 51 Pegasi. Description Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Research In Astronomy And Astrophysics
''Research in Astronomy and Astrophysics'' is a monthly peer-reviewed scientific journal covering all branches of astronomy and astrophysics. It was established in 1981 as ''Acta Astrophysica Sinica'' and published in Chinese. It was renamed ''Chinese Journal of Astronomy and Astrophysics'' in 2001, switching to publication in English and restarting volume numbering. It obtained its current name in 2009. The journal is published by IOP Publishing, on behalf of the National Astronomical Observatory of China and the Chinese Astronomical Society. The editor-in-chief is Jingxiu Wang (National Astronomical Observatory of China). According to the ''Journal Citation Reports'', the journal has a 2023 impact factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a type of journal ranking. Journals with higher impact factor values are considered more prestigious or important within their field. The Impact Factor of a journa ... of 1.8. References Ex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Extrasolar Planets
A list is a set of discrete items of information collected and set forth in some format for utility, entertainment, or other purposes. A list may be memorialized in any number of ways, including existing only in the mind of the list-maker, but lists are frequently written down on paper, or maintained electronically. Lists are "most frequently a tool", and "one does not ''read'' but only ''uses'' a list: one looks up the relevant information in it, but usually does not need to deal with it as a whole".Lucie Doležalová,The Potential and Limitations of Studying Lists, in Lucie Doležalová, ed., ''The Charm of a List: From the Sumerians to Computerised Data Processing'' (2009). Purpose It has been observed that, with a few exceptions, "the scholarship on lists remains fragmented". David Wallechinsky, a co-author of '' The Book of Lists'', described the attraction of lists as being "because we live in an era of overstimulation, especially in terms of information, and lists help us ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HD 142415
HD 142415 is a single star in the southern constellation of Norma, positioned next to the southern constellation border with Triangulum Australe and less than a degree to the west of NGC 6025. With an apparent visual magnitude of 7.33, it is too faint to be visible to the naked eye. The distance to this star is 116 light years from the Sun based on parallax, but it is drifting closer with a radial velocity of −12 km/s. It is a candidate member of the NGC 1901 open cluster of stars. This is an ordinary G-type main-sequence star with a stellar classification of G1V. It has been identified as a solar twin by Datson et al. (2012), which means its physical properties are very similar to the Sun. It has 10% more mass than the Sun but only a 3% larger radius. The star is estimated to be 1.6 billion years old and is spinning with a projected rotational velocity of 4.2 km/s. It is radiating 1.16 times the luminosity of the Sun from its photosphere at an eff ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HD 141937
HD 141937 is a star in the southern zodiac constellation of Libra, positioned a couple of degrees to the north of Lambda Librae. It is a yellow-hued star with an apparent visual magnitude of 7.25, which means it is too faint to be seen with the naked eye. This object is located at a distance of 108.9 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −2.2 km/s. It has an absolute magnitude of 4.71. This is a G-type main-sequence star with a stellar classification of G1V. It is a solar-type star with slightly higher mass and radius compared to the Sun. The metallicity is higher than solar. It is an estimated 3.8 billion years old and is spinning with a projected rotational velocity of 6 km/s. The star is radiating 1.2 times the luminosity of the Sun from its photosphere at an effective temperature of 5,890 K. The star has a substellar companion (HD 141937 b) announced in April 2001 by the European South ... [...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 Astronomical object, 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 the ancient Greek astronomer 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, the Iranian astronomer Abd al-Rahman al-Sufi carried ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
True Mass
In astronomy, minimum mass is the lower-bound calculated mass of observed objects such as planets, stars, binary systems, nebulae, and black holes. Minimum mass is a widely cited statistic for extrasolar planets detected by the radial velocity method or Doppler spectroscopy, and is determined using the binary mass function. This method reveals planets by measuring changes in the movement of stars in the line-of-sight, so the real orbital inclinations and true masses of the planets are generally unknown. This is a result of sin ''i'' degeneracy. If inclination ''i'' can be determined, the true mass can be obtained from the calculated minimum mass using the following relationship: M_\text = \frac Exoplanets Orientation of the transit to Earth Most stars will not have their planets lined up and orientated so that they eclipse over the center of the star and give the viewer on earth a perfect transit. It is for this reason that when we often are only able to extrapolate a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HD 142022 Ab
HD 142022 Ab is an exoplanet discovered by the radial velocity method by Eggenberger ''et al.'' in 2005, after finding that HD 142022 A is wobbling which indicated the presence of a massive planet, with a minimum mass 4.5 times Jupiter. It has a relatively wide separation between the planet and the star of nearly 3 AU, and takes 1928 days or 5.28 years to revolve. As is common for long-period planets, it has a relatively high eccentricity of 53±20%. In 2023, the inclination and true mass of HD 142022 Ab were determined via astrometry. See also * HD 141937 b * HD 142415 b HD 142415 b is an exoplanet with the semi-amplitude of 51.3 ± 2.3 m/s. This indicates the minimum mass of 1.69 Jupiter mass, an orbital period of 386.3 days, and the semi-major axis of 1.07 astronomical units based from its stellar mass. The wil ... References External links * Exoplanets discovered in 2005 Giant planets Octans Exoplanets detected by radial velocity Exoplanets detected by as ... [...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] |
