This Sample of 313 Stars, Our Own Sun Included (“Sample S”), Is Found to Lie in a Region, Around 3000 Ly in Radius, Essenti
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The Very Long Mystery of Epsilon Aurigae
A Unique Eclipsing Variable TheThe VeryVery LongLong MMysteryystery ofof EpsilonEpsilon AAurigaeurigae robertrobert e. sstenceltencel one of the great scientifi c advances of the 20th A remarkable naked-eye star century was the theory of stellar evolution, as physicists worked out not just how stars shine, but how they origi- will soon start dimming for nate, live, change, and die. To test theory against reality, however, astronomers had to determine accurate masses the eighth time since 1821. for many diff erent kinds of stars — and this meant analyz- What’s going on is still ing the motions of binary pairs. Theorists also needed the stars’ exact diameters, and this meant analyzing the light not exactly clear. curves of eclipsing binaries in particular. A century ago, S&T ILLUSTRATION BY CASEY REED giants of early astrophysics worked intensely on the prob- lem of eclipsing-binary analysis. Henry Norris Russell’s paper “On the Determination of the Orbital Elements of Eclipsing Variable Stars,” published in 1912, set the stage for what followed. BIG WHITE STAR, BIGGER BLACK PARTNER Epsilon Aurigae, hotter than the Sun and larger than Earth’s entire orbit, pours forth some 130,000 times the Sun’s light — which is why it shines as brightly as 3rd magnitude even from 2,000 light-years away. According to the currently favored model, a long, dark object will start sliding across its middle this summer. The object seems to be an opaque warped disk 10 a.u. wide and appearing roughly 1 a.u. tall. Whatever lies at its center seems to be hidden — though there’s also evidence that we see right through the center. -
Aerodynamic Phenomena in Stellar Atmospheres, a Bibliography
- PB 151389 knical rlote 91c. 30 Moulder laboratories AERODYNAMIC PHENOMENA STELLAR ATMOSPHERES -A BIBLIOGRAPHY U. S. DEPARTMENT OF COMMERCE NATIONAL BUREAU OF STANDARDS ^M THE NATIONAL BUREAU OF STANDARDS Functions and Activities The functions of the National Bureau of Standards are set forth in the Act of Congress, March 3, 1901, as amended by Congress in Public Law 619, 1950. These include the development and maintenance of the national standards of measurement and the provision of means and methods for making measurements consistent with these standards; the determination of physical constants and properties of materials; the development of methods and instruments for testing materials, devices, and structures; advisory services to government agencies on scientific and technical problems; in- vention and development of devices to serve special needs of the Government; and the development of standard practices, codes, and specifications. The work includes basic and applied research, development, engineering, instrumentation, testing, evaluation, calibration services, and various consultation and information services. Research projects are also performed for other government agencies when the work relates to and supplements the basic program of the Bureau or when the Bureau's unique competence is required. The scope of activities is suggested by the listing of divisions and sections on the inside of the back cover. Publications The results of the Bureau's work take the form of either actual equipment and devices or pub- lished papers. -
Maps for GLOBE at Night at Latitude 40 , February 23, 21 H Local Time
< 0.50 mag < 1.50 mag < 2.50 mag < 3.50 mag < 4.50 mag < 5.50 mag < 6.50 mag < 7.50 mag Maps for GLOBE at Night at latitude 40◦, February 23, 21 h local time (deep night), assuming rather transparent air. Orion’s belt is 34◦ to the right from the south, at 43◦ height. The brightest fixed star, Sirius, is at left. Jan Hollan, Ecological Institute Veronica and http://www.astro.cz/darksky < 0.50 mag < 1.50 mag < 2.50 mag < 3.50 mag < 4.50 mag < 5.50 mag < 6.50 mag < 7.50 mag Maps for GLOBE at Night at latitude 40◦, March 2, 21 h local time (deep night), assuming rather transparent air. Orion’s belt is 42◦ to the right from the south, at 40◦ height. The brightest fixed star, Sirius, is at left. Jan Hollan, Ecological Institute Veronica and http://www.astro.cz/darksky Betelgeuse Rigel Pollux Procyon Sirius Sirius Arcturus Saturn < 0.50 mag < 1.50 mag S S Betelgeuse Big Dipper Big Big Dipper Big Betelgeuse Rigel Rigel Pollux Pollux Procyon Procyon Sirius Sirius Arcturus Regulus Arcturus Regulus Denebola Denebola Saturn Saturn < 2.50 mag < 3.50 mag S S Procyon Procyon Regulus Regulus Denebola Denebola < 4.50 mag < 5.50 mag Procyon Procyon Regulus Regulus Denebola Denebola < 6.50 mag < 7.50 mag Maps for GLOBE at Night at latitude 40◦, March 23, 21 h local time (Sun at -31◦). Lines from N(E,S,W) to zenith shown (crosses each 10◦). Regulus (α Leonis) is 32◦ to the left from S, at 58◦ height. -
Abd Al-Rahman Al-Sufi and His Book of the Fixed Stars: a Journey of Re-Discovery
ResearchOnline@JCU This file is part of the following reference: Hafez, Ihsan (2010) Abd al-Rahman al-Sufi and his book of the fixed stars: a journey of re-discovery. PhD thesis, James Cook University. Access to this file is available from: http://eprints.jcu.edu.au/28854/ The author has certified to JCU that they have made a reasonable effort to gain permission and acknowledge the owner of any third party copyright material included in this document. If you believe that this is not the case, please contact [email protected] and quote http://eprints.jcu.edu.au/28854/ 5.1 Extant Manuscripts of al-Ṣūfī’s Book Al-Ṣūfī’s ‘Book of the Fixed Stars’ dating from around A.D. 964, is one of the most important medieval Arabic treatises on astronomy. This major work contains an extensive star catalogue, which lists star co-ordinates and magnitude estimates, as well as detailed star charts. Other topics include descriptions of nebulae and Arabic folk astronomy. As I mentioned before, al-Ṣūfī’s work was first translated into Persian by al-Ṭūsī. It was also translated into Spanish in the 13th century during the reign of King Alfonso X. The introductory chapter of al-Ṣūfī’s work was first translated into French by J.J.A. Caussin de Parceval in 1831. However in 1874 it was entirely translated into French again by Hans Karl Frederik Schjellerup, whose work became the main reference used by most modern astronomical historians. In 1956 al-Ṣūfī’s Book of the fixed stars was printed in its original Arabic language in Hyderabad (India) by Dārat al-Ma‘aref al-‘Uthmānīa. -