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Helmut A. Abt
Helmut Arthur Abt (26 May 1925 – 22 November 2024) was a German-born American astrophysicist, having worked at the National Optical Astronomy Observatory and an Elected Fellow of the American Association for the Advancement of Science. He was astronomer emeritus at Kitt Peak National Observatory. Life and career Helmut Arthur Abt was born in Helmstedt, Germany on 26 May 1925. His family emigrated to the United States when he was two. He received his B.S. in Mathematics from Northwestern University in 1946, M.S. in Physics from Northwestern University in 1948, and became the first person to be awarded a Ph.D. in astrophysics at California Institute of Technology in 1952 for his thesis work on W Virginis. He then spent a year at Lick Observatory. From 1953 to 1959 he was assistant professor at Yerkes Observatory, part of the University of Chicago, then joined the staff of the Kitt Peak National Observatory as an astronomer, where he remained until 2000. From 1966 to 1968, he ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NOIRLab
The National Optical-Infrared Astronomy Research Laboratory (NOIRLab) is the United States' national facility for ground-based, night-time optical and infrared astronomy. It is funded by the National Science Foundation (NSF) and operated by the Association of Universities for Research in Astronomy (AURA), as a federally funded research and development center. NOIRLab runs four observatories and a center for scientific software and research data archiving. It provides access to observing time for astronomers affiliated with any US institution. History NOIRLab was formed in 2019 by the merger of three predecessor organizations, which were all managed by AURA and funded by NSF. They were: *The National Optical Astronomy Observatory (NOAO), which managed Kitt Peak Observatory in Arizona, Cerro Tololo Observatory in Chile, and the Community Science and Data Center *The Gemini Observatory, which operated Gemini North in Hawaii and Gemini South in Chile *The Vera C. Rubin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
W Virginis
W Virginis is the prototype W Virginis variable, a subclass of the Cepheid variable stars. It is located in the constellation Virgo (constellation), Virgo, and varies between magnitudes 9.46 and 10.75 over a period of approximately 17 days. There are variations in the light curve apparently due to multiple pulsation periods rather than inherent instabilities in the pulsation. The dominant pulsation mode has a period of 17.27134 days with a period decrease detected over a 75-year period. The pulsations cause changes in both temperature and size, leading to large changes in the luminosity and brightness. The maximum temperature occurs when the star is at its brightest visually, when the star is also at its smallest. The minimum temperature and maximum radius occur at around phase 0.5 when the brightness is decreasing and nearly at minimum. Because relatively more infrared radiation is produced when the star is cooler, the maximum brightness in the infrared occurs when th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
9423 Abt
9423 Abt, provisional designation ', is a stony background asteroid from the central region of the asteroid belt, approximately 13 kilometers in diameter. It was discovered on 12 January 1996, by the Spacewatch project of the University of Arizona at Kitt Peak National Observatory, United States. The asteroid was named after American astronomer Helmut Abt. Orbit and classification ''Abt'' is a non-family asteroid from the main belt's background population. It orbits the Sun in the central main-belt at a distance of 2.4–3.0 AU once every 4 years and 5 months (1,614 days). Its orbit has an eccentricity of 0.10 and an inclination of 9 ° with respect to the ecliptic. It was first identified as at Crimea-Nauchnij in February 1974, extending the body's observation arc by 22 years prior to its official discovery observation at Kitt Peak. Naming This minor planet was named after American astrophysicist Helmut Abt (born 1925), one of the founders of the discovering Kitt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Main-belt
The asteroid belt is a torus-shaped region in the Solar System, centered on the Sun and roughly spanning the space between the orbits of the planets Jupiter and Mars. It contains a great many solid, irregularly shaped bodies called asteroids or minor planets. The identified objects are of many sizes, but much smaller than planets, and, on average, are about one million kilometers (or six hundred thousand miles) apart. This asteroid belt is also called the main asteroid belt or main belt to distinguish it from other asteroid populations in the Solar System. The asteroid belt is the smallest and innermost circumstellar disc in the Solar System. Classes of small Solar System bodies in other regions are the near-Earth objects, the centaurs, the Kuiper belt objects, the scattered disc objects, the sednoids, and the Oort cloud objects. About 60% of the main belt mass is contained in the four largest asteroids: Ceres, Vesta, Pallas, and Hygiea. The total mass of the asteroid be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astronomy
Astronomy is a natural science that studies celestial objects and the phenomena that occur in the cosmos. It uses mathematics, physics, and chemistry in order to explain their origin and their overall evolution. Objects of interest include planets, natural satellite, moons, stars, nebulae, galaxy, galaxies, meteoroids, asteroids, and comets. Relevant phenomena include supernova explosions, gamma ray bursts, quasars, blazars, pulsars, and cosmic microwave background radiation. More generally, astronomy studies everything that originates beyond atmosphere of Earth, Earth's atmosphere. Cosmology is a branch of astronomy that studies the universe as a whole. Astronomy is one of the oldest natural sciences. The early civilizations in recorded history made methodical observations of the night sky. These include the Egyptian astronomy, Egyptians, Babylonian astronomy, Babylonians, Greek astronomy, Greeks, Indian astronomy, Indians, Chinese astronomy, Chinese, Maya civilization, M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bibliometrics
Bibliometrics is the application of statistical methods to the study of bibliographic data, especially in scientific and library and information science contexts, and is closely associated with scientometrics (the analysis of scientific metrics and indicators) to the point that both fields largely overlap. Bibliometrics studies first appeared in the late 19th century. They have known a significant development after the Second World War in a context of "periodical crisis" and new technical opportunities offered by computing tools. In the early 1960s, the Science Citation Index of Eugene Garfield and the citation network analysis of Derek John de Solla Price laid the fundamental basis of a structured research program on bibliometrics. Citation analysis is a commonly used bibliometric method based on constructing the citation graph, a network or graph representation of the citations shared by documents. Many research fields use bibliometric methods to explore the impact of their ... [...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] |
Spectroscopic Binaries
A binary star or binary star system is a Star system, system of two stars that are gravity, gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved as separate stars using a telescope, in which case they are called ''visual binaries''. Many visual binaries have long orbital periods of several centuries or millennia and therefore have orbits which are uncertain or poorly known. They may also be detected by indirect techniques, such as spectroscopy (''spectroscopic binaries'') or astrometry (''astrometric binaries''). If a binary star happens to orbit in a plane along our line of sight, its components will eclipse and transit (astronomy), transit each other; these pairs are called ''eclipsing binaries'', or, together with other binaries that change brightness as they orbit, ''photometric binaries''. If components in binary star systems are close enough, they can gravitationally distort ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Binary Star
A binary star or binary star system is a system of two stars that are gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved as separate stars using a telescope, in which case they are called ''visual binaries''. Many visual binaries have long orbital periods of several centuries or millennia and therefore have orbits which are uncertain or poorly known. They may also be detected by indirect techniques, such as spectroscopy (''spectroscopic binaries'') or astrometry (''astrometric binaries''). If a binary star happens to orbit in a plane along our line of sight, its components will eclipse and transit each other; these pairs are called ''eclipsing binaries'', or, together with other binaries that change brightness as they orbit, ''photometric binaries''. If components in binary star systems are close enough, they can gravitationally distort each other's outer stellar atmospheres. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stellar Rotation
Stellar rotation is the angular motion of a star about its axis. The rate of rotation can be measured from the spectrum of the star, or by timing the movements of active features on the surface. The rotation of a star produces an equatorial bulge due to centrifugal force. As stars are not solid bodies, they can also undergo differential rotation. Thus the equator of the star can rotate at a different angular velocity than the higher latitudes. These differences in the rate of rotation within a star may have a significant role in the generation of a stellar magnetic field. In its turn, the magnetic field of a star interacts with the stellar wind. As the wind moves away from the star its angular speed decreases. The magnetic field of the star interacts with the wind, which applies a drag to the stellar rotation. As a result, angular momentum is transferred from the star to the wind, and over time this gradually slows the star's rate of rotation. Measurement Unless a star ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astrophysical Journal
''The Astrophysical Journal'' (''ApJ'') 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 until, in January 2009, publication was transferred to IOP Publis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astronomical Society Of The Pacific
The Astronomical Society of the Pacific (ASP) is an American scientific and educational organization, founded in San Francisco on February 7, 1889, immediately following the solar eclipse of January 1, 1889. Its name derives from its origins on the Pacific Coast, but today it has members all over the country and the world. It has the legal status of a nonprofit organization. It is the largest general astronomy education society in the world, with members from over 40 countries. Education and outreach programs The ASP's mission is to promote public interest in and awareness of astronomy (and increase scientific literacy) through its publications, web site, and many educational and outreach programs. * The NASA Night Sky Network – a community of more than 450 astronomy clubs across the U.S. that share their time and telescopes to engage the public with unique astronomy experiences. The ASP provides training and materials to enhance clubs outreach activities, and inspires more ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
