|
Methuselah Star
HD 140283 (also known as the Methuselah star) is a metal-poor subgiant star about 190 light years away from the Earth in the constellation Libra, near the boundary with Ophiuchus in the Milky Way Galaxy. Its apparent magnitude is 7.205. It is one of the oldest stars known. The star's light is somewhat blueshifted as it is moving toward rather than away from the Earth and it has been known to astronomers for over a century as a high-velocity star based on its other vectors (proper motion). An early spectroscopic analysis by Joseph W. Chamberlain and Lawrence Aller revealed it to have a substantially lower metal content than the Sun. Modern spectroscopic analyses find an iron content about a factor of 250 lower than that of the Sun. It is one of the closest metal-poor ( Population II) stars to Earth. The star was already known by 1912 when W. S. Adams measured its astrometry using a spectrograph in the Mount Wilson Observatory. Age and sign ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oldest Star In Solar Neighbourhood
Old or OLD may refer to: Places * Old, Baranya, Hungary * Old, Northamptonshire, England *Old Street station, a railway and tube station in London (station code OLD) *OLD, IATA code for Old Town Municipal Airport and Seaplane Base, Old Town, Maine, United States People *Old (surname) Music *OLD (band), a grindcore/industrial metal group * ''Old'' (Danny Brown album), a 2013 album by Danny Brown * ''Old'' (Starflyer 59 album), a 2003 album by Starflyer 59 * "Old" (song), a 1995 song by Machine Head *'' Old LP'', a 2019 album by That Dog Other uses * ''Old'' (film), a 2021 American thriller film *'' Oxford Latin Dictionary'' * Online dating *Over-Locknut Distance (or Dimension), a measurement of a bicycle wheel and frame * Old age See also * List of people known as the Old * * *Olde, a list of people with the surname *Olds (other) Olds may refer to: People * The olds, a jocular and irreverent online nickname for older adults * Bert Olds (1891–1953), Australia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blueshift
In physics, a redshift is an increase in the wavelength, and corresponding decrease in the frequency and photon energy, of electromagnetic radiation (such as light). The opposite change, a decrease in wavelength and simultaneous increase in frequency and energy, is known as a negative redshift, or blueshift. The terms derive from the colours red and blue which form the extremes of the visible light spectrum. In astronomy and cosmology, the three main causes of electromagnetic redshift are # The radiation travels between objects which are moving apart (" relativistic" redshift, an example of the relativistic Doppler effect) #The radiation travels towards an object in a weaker gravitational potential, i.e. towards an object in less strongly curved (flatter) spacetime (gravitational redshift) #The radiation travels through expanding space ( cosmological redshift). The observation that all sufficiently distant light sources show redshift corresponding to their distance from Ea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hertzsprung–Russell Diagram
The Hertzsprung–Russell diagram, abbreviated as H–R diagram, HR diagram or HRD, is a scatter plot of stars showing the relationship between the stars' absolute magnitudes or luminosities versus their stellar classifications or effective temperatures. The diagram was created independently in 1911 by Ejnar Hertzsprung and by Henry Norris Russell in 1913, and represented a major step towards an understanding of stellar evolution. Historical background In the nineteenth century large-scale photographic spectroscopic surveys of stars were performed at Harvard College Observatory, producing spectral classifications for tens of thousands of stars, culminating ultimately in the Henry Draper Catalogue. In one segment of this work Antonia Maury included divisions of the stars by the width of their spectral lines. Hertzsprung noted that stars described with narrow lines tended to have smaller proper motions than the others of the same spectral classification. He took this as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Red Giant
A red giant is a luminous giant star of low or intermediate mass (roughly 0.3–8 solar masses ()) in a late phase of stellar evolution. The outer atmosphere is inflated and tenuous, making the radius large and the surface temperature around or lower. The appearance of the red giant is from yellow-white to reddish-orange, including the spectral types K and M, sometimes G, but also class S stars and most carbon stars. Red giants vary in the way by which they generate energy: * most common red giants are stars on the red-giant branch (RGB) that are still fusing hydrogen into helium in a shell surrounding an inert helium core * red-clump stars in the cool half of the horizontal branch, fusing helium into carbon in their cores via the triple-alpha process * asymptotic-giant-branch (AGB) stars with a helium burning shell outside a degenerate carbon–oxygen core, and a hydrogen-burning shell just beyond that. Many of the well-known bright stars are red giants because they ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Main Sequence
In astronomy, the main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Hertzsprung and Henry Norris Russell. Stars on this band are known as main-sequence stars or dwarf stars. These are the most numerous true stars in the universe and include the Sun. After condensation and ignition of a star, it generates thermal energy in its dense core region through nuclear fusion of hydrogen into helium. During this stage of the star's lifetime, it is located on the main sequence at a position determined primarily by its mass but also based on its chemical composition and age. The cores of main-sequence stars are in hydrostatic equilibrium, where outward thermal pressure from the hot core is balanced by the inward pressure of gravitational collapse from the overlying layers. The strong dependence of the rate of ene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mount Wilson Observatory
The Mount Wilson Observatory (MWO) is an astronomical observatory in Los Angeles County, California, United States. The MWO is located on Mount Wilson, a peak in the San Gabriel Mountains near Pasadena, northeast of Los Angeles. The observatory contains two historically important telescopes: the Hooker telescope, which was the largest aperture telescope in the world from its completion in 1917 to 1949, and the 60-inch telescope which was the largest operational telescope in the world when it was completed in 1908. It also contains the Snow solar telescope completed in 1905, the 60 foot (18 m) solar tower completed in 1908, the 150 foot (46 m) solar tower completed in 1912, and the CHARA array, built by Georgia State University, which became fully operational in 2004 and was the largest optical interferometer in the world at its completion. Due to the inversion layer that traps warm air and smog over Los Angeles, Mount Wilson has steadier air than any other location in Nor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spectrograph
An optical spectrometer (spectrophotometer, spectrograph or spectroscope) is an instrument used to measure properties of light over a specific portion of the electromagnetic spectrum, typically used in spectroscopic analysis to identify materials. The variable measured is most often the light's intensity but could also, for instance, be the polarization state. The independent variable is usually the wavelength of the light or a unit directly proportional to the photon energy, such as reciprocal centimeters or electron volts, which has a reciprocal relationship to wavelength. A spectrometer is used in spectroscopy for producing spectral lines and measuring their wavelengths and intensities. Spectrometers may operate over a wide range of non-optical wavelengths, from gamma rays and X-rays into the far infrared. If the instrument is designed to measure the spectrum on an absolute scale rather than a relative one, then it is typically called a spectrophotometer. The major ... [...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] |
Walter Sydney Adams
Walter Sydney Adams (December 20, 1876 – May 11, 1956) was an American astronomer. Life and work Adams was born in Antioch, Turkey, to Lucien Harper Adams and Nancy Dorrance Francis Adams, missionary parents, and was brought to the U.S. in 1885 He graduated from Dartmouth College in 1898, then continued his education in Chicago and in Germany. After returning to the U.S., he began a career in Astronomy that culminated when he became director of the Mount Wilson Observatory. His primary interest was the study of stellar spectra. He worked on solar spectroscopy and co-discovered a relationship between the relative intensities of certain spectral lines and the absolute magnitude of a star. He was able to demonstrate that spectra could be used to determine whether a star was a giant or a dwarf. In 1915 he began a study of the companion of Sirius and found that despite a size only slightly larger than the Earth, the surface of the star was brighter per unit area than the Su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1912 In Science
The year 1912 in science and technology involved some significant events, listed below. Archaeology * December 6 – The Nefertiti bust is found at Amarna in Egypt by the German Oriental Company (Deutsche Orient-Gesellschaft – DOG), led by German archaeologist Ludwig Borchardt. Astronomy * At the beginning of this year an extreme decadal variation in length of day produces mean solar days having a duration of 86400.00389 seconds of Terrestrial Time (or ephemeris time), the slowest rotation of Earth's crust ever to be recorded. Biology * July 23 – Horace Donisthorpe first discovers '' Anergates atratulus'' in the New Forest, England. * Reginald Punnett is appointed as first Arthur Balfour Professor of Genetics in the University of Cambridge (U.K.), probably the oldest chair of genetics in the English-speaking world. Chemistry * Peter Debye derives the T-cubed law for the low temperature heat capacity of a nonmetallic solid. * Casimir Funk introduces the concept of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Population II Stars
During 1944, Walter Baade categorized groups of stars within the Milky Way into stellar populations. In the abstract of the article by Baade, he recognizes that Jan Oort originally conceived this type of classification in 1926: Baade noticed that bluer stars were strongly associated with the spiral arms, and yellow stars dominated near the central galactic bulge and within globular star clusters. Two main divisions were defined as * Population I and * Population II, with another newer, hypothetical division called * Population III added in 1978; they are often simply abbreviated as Pop. I, Pop. II, and Pop. III. Among the population types, significant differences were found with their individual observed stellar spectra. These were later shown to be very important and were possibly related to star formation, observed kinematics, stellar age, and even galaxy evolution in both spiral and elliptical galaxies. These three simple population classes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.jpg "Click for more on -> Red Giant")
.jpg "Click for more on -> Population II Stars")