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Roger Cayrel
Roger Victor Émile Cayrel (4 December 1925 – 11 January 2021) was a French astronomer. His main interests were stellar atmospheres, galactic chemical evolution and metal-poor stars. Biography Born in Bordeaux, France, he attended the ''Lycée Michel-Montaigne'' in Bordeaux and studied physics at the École normale supérieure and the ''Faculté des sciences de Paris''. Beside his scientific work, he had a number of high-ranking posts in the management of science: director of the Canada-France-Hawaii Telescope (CFHT, 1974–1980), president of the IAU commission on stellar atmospheres (1973–1976) and head of the Bureau des Longitudes (1995–1996). Cayrel was a corresponding member of the Académie des Sciences from 1988 to 2021. He was awarded the Prix Jules Janssen of the Société astronomique de France (Astronomical Society of France), in 2001. Cayrel and his colleagues discovered thorium and uranium in the ultra-metal-poor halo star BPS CS31082-0001, which was named Ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astronomer
An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, natural satellite, moons, comets and galaxy, galaxies – in either observational astronomy, observational (by analyzing the data) or theoretical astronomy. Examples of topics or fields astronomers study include planetary science, Sun, solar astronomy, the Star formation, origin or stellar evolution, evolution of stars, or the galaxy formation and evolution, formation of galaxies. A related but distinct subject is physical cosmology, which studies the Universe as a whole. Types Astronomers usually fall under either of two main types: observational astronomy, observational and theoretical astronomy, theoretical. Observational astronomers make direct observations of Astronomical object, celestial objects and analyze the data. In contrast, theoretical astronomers create and investigate C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thorium
Thorium is a weakly radioactive metallic chemical element with the symbol Th and atomic number 90. Thorium is silvery and tarnishes black when it is exposed to air, forming thorium dioxide; it is moderately soft and malleable and has a high melting point. Thorium is an electropositive actinide whose chemistry is dominated by the +4 oxidation state; it is quite reactive and can ignite in air when finely divided. All known thorium isotopes are unstable. The most stable isotope, 232Th, has a half-life of 14.05 billion years, or about the age of the universe; it decays very slowly via alpha decay, starting a decay chain named the thorium series that ends at stable 208 Pb. On Earth, thorium and uranium are the only significantly radioactive elements that still occur naturally in large quantities as primordial elements. Thorium is estimated to be over three times as abundant as uranium in the Earth's crust, and is chiefly refined from monazite sands as a by-product of extracti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2021 Deaths
This is a list of deaths of notable people, organised by year. New deaths articles are added to their respective month (e.g., Deaths in ) and then linked here. 2022 2021 2020 2019 2018 2017 2016 2015 2014 2013 2012 2011 2010 2009 2008 2007 2006 2005 2004 2003 2002 2001 2000 1999 1998 1997 1996 1995 1994 1993 1992 1991 1990 1989 1988 1987 See also * Lists of deaths by day The following pages, corresponding to the Gregorian calendar, list the historical events, births, deaths, and holidays and observances of the specified day of the year: Footnotes See also * Leap year * List of calendars * List of non-standard ... * Deaths by year {{DEFAULTSORT:deaths by year ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1925 Births
Nineteen or 19 may refer to: * 19 (number), the natural number following 18 and preceding 20 * one of the years 19 BC, AD 19, 1919, 2019 Films * ''19'' (film), a 2001 Japanese film * ''Nineteen'' (film), a 1987 science fiction film Music * 19 (band), a Japanese pop music duo Albums * ''19'' (Adele album), 2008 * ''19'', a 2003 album by Alsou * ''19'', a 2006 album by Evan Yo * ''19'', a 2018 album by MHD * ''19'', one half of the double album ''63/19'' by Kool A.D. * ''Number Nineteen'', a 1971 album by American jazz pianist Mal Waldron * ''XIX'' (EP), a 2019 EP by 1the9 Songs * "19" (song), a 1985 song by British musician Paul Hardcastle. * "Nineteen", a song by Bad4Good from the 1992 album '' Refugee'' * "Nineteen", a song by Karma to Burn from the 2001 album ''Almost Heathen''. * "Nineteen" (song), a 2007 song by American singer Billy Ray Cyrus. * "Nineteen", a song by Tegan and Sara from the 2007 album '' The Con''. * "XIX" (song), a 2014 song by Slip ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Francesca Primas
Francesca Primas is an Italian astronomer at the European Southern Observatory in Germany. Her research studies the historical evolution of chemical abundances in the Milky Way and its satellite galaxies; she is also known for her activism for improving the gender balance of professional astronomy. Education and career Primas was a high school student in Gorizia, and studied astronomy at the University of Trieste, both in Italy. She earned a laurea (the Italian equivalent of a master's degree) in 1992, and completed a PhD there in 1995. After postdoctoral research at the University of Chicago in the US from 1995 to 1997, and at the European Southern Observatory from 1997 to 2000, she continued at the European Southern Observatory as a support astronomer beginning in 2000, became head of the user support department in 2006, and was promoted to full astronomer in 2015. In approximately 2008, she authored a study of gender distribution among European Southern Observatory astrono ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Giuseppina De Strobel
''Giuseppina'' is a 1960 short British documentary film produced by James Hill, which was filmed in 1959, in Mandriole, Emilia-Romagna, near Ravenna in the north east of Italy. It won the Academy Award for Best Documentary (Short Subject). Production of the film was sponsored by the British Petroleum company (BP), which also distributed the film. The BP webpage summarizes the film as, "set at an Italian petrol station where various characters pass through on their onward journey, while entertaining and playing with the attendant's daughter, Giuseppina." In the 1960s and early 1970s, ''Giuseppina'' was broadcast 185 times on British television as a trade test colour film.Keys, Andrew (2007)."The Statistician's Guide to Trade Test Colour Films" webpage of the "Test Card Circle" website archived at WebCite fro18 June 2008. Excerpts were also shown on '' Vision On'', the BBC programme for deaf and hard-of-hearing children. It was released as an extra on the BFI Flipside DVD relea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cayrel's Star
BPS CS31082-0001, named Cayrel's Star , is an old Population II star located in a distance of 2.1 kpc in the galactic halo. It belongs to the class of ultra-metal-poor stars (metallicity Fe/Hydrogen.html"_;"title="Iron.html"_;"title="/nowiki>Iron">Fe/Hydrogen">H.html" ;"title="Iron">Fe/Hydrogen.html" ;"title="Iron.html" ;"title="/nowiki>Iron">Fe/Hydrogen">H">Iron">Fe/Hydrogen.html" ;"title="Iron.html" ;"title="/nowiki>Iron">Fe/Hydrogen">H/nowiki> = -2.9), specifically the very rare subclass of neutron-capture enhanced stars. It was discovered by Tim C. Beers and collaborators with the Curtis Schmidt telescope at the Cerro Tololo Inter-American Observatory in Chile and analyzed by Roger Cayrel and collaborators. They used the Very Large Telescope ( Very Large Telescope, VLT) at the European Southern Observatory in Paranal, Chile for high-resolution optical spectroscopy to determine elemental abundances. The thorium-232 to uranium-238 ratio was used to determine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uranium
Uranium is a chemical element with the symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weakly radioactive because all isotopes of uranium are unstable; the half-lives of its naturally occurring isotopes range between 159,200 years and 4.5 billion years. The most common isotopes in natural uranium are uranium-238 (which has 146 neutrons and accounts for over 99% of uranium on Earth) and uranium-235 (which has 143 neutrons). Uranium has the highest atomic weight of the primordially occurring elements. Its density is about 70% higher than that of lead, and slightly lower than that of gold or tungsten. It occurs naturally in low concentrations of a few parts per million in soil, rock and water, and is commercially extracted from uranium-bearing minerals such as uraninite. In nature, uranium is found as uranium-238 (99. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Société Astronomique De France
The Société astronomique de France (SAF; ), the French astronomical society, is a non-profit association in the public interest organized under French law (Association loi de 1901). Founded by astronomer Camille Flammarion in 1887, its purpose is to promote the development and practice of astronomy. History SAF was established by Camille Flammarion and a group of 11 persons on 28 January 1887 in Flammarion's apartment at 16 rue Cassini, 75014 Paris, close to the Paris Observatory. Open to all, SAF includes both professional and amateur astronomers as members, from France and abroad.Ferlet R. (2003) "The Société Astronomique de France in the Astronomical Landscape: Evolution and Prospects." In: ''Organizations and Strategies in Astronomy''. Astrophysics and Space Science Library, vol 296. Springer, Dordrecht. Its objective was defined at the time of its establishment as: "A Society is founded with the aim to bring together people involved practically or theoretically in As ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stellar Atmosphere
The stellar atmosphere is the outer region of the volume of a star, lying above the stellar core, radiation zone and convection zone. Overview The stellar atmosphere is divided into several regions of distinct character: * The photosphere, which is the atmosphere's lowest and coolest layer, is normally its only visible part. Light escaping from the surface of the star stems from this region and passes through the higher layers. The Sun's photosphere has a temperature in the 5,770 K to 5,780 K range. Starspots, cool regions of disrupted magnetic field lie on the photosphere. * Above the photosphere lies the chromosphere. This part of the atmosphere first cools down and then starts to heat up to about 10 times the temperature of the photosphere. * Above the chromosphere lies the transition region, where the temperature increases rapidly on a distance of only around 100 km. * The outermost part of the stellar atmosphere is the corona, a tenuous plasma which has a tem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prix Jules Janssen
The Prix Jules Janssen is the highest award of the Société astronomique de France (SAF), the French astronomical society. This annual prize is given to a professional French astronomer or to an astronomer of another nationality in recognition of astronomical work in general, or for services rendered to Astronomy. The first recipient of the prize was Camille Flammarion, the founder of the Société astronomique de France, in 1897. The prize has been continuously awarded since then with the exception of the two World Wars. Non-French recipients have come from various countries including the United States, the United Kingdom, Canada, Switzerland, the Netherlands, Germany, Belgium, Sweden, Italy, Spain, Hungary, India, the former Czechoslovakia, and the former Soviet Union. It was established by the French astronomer Pierre Jules César Janssen (known as Jules Janssen) during his tenure as president of SAF from 1895 to 1897. Janssen announced the creation of the new prize at a meet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
