Almanacco Astronomico 2002 – Introduzione
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Durham E-Theses
Durham E-Theses First visibility of the lunar crescent and other problems in historical astronomy. Fatoohi, Louay J. How to cite: Fatoohi, Louay J. (1998) First visibility of the lunar crescent and other problems in historical astronomy., Durham theses, Durham University. Available at Durham E-Theses Online: http://etheses.dur.ac.uk/996/ Use policy The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that: • a full bibliographic reference is made to the original source • a link is made to the metadata record in Durham E-Theses • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders. Please consult the full Durham E-Theses policy for further details. Academic Support Oce, Durham University, University Oce, Old Elvet, Durham DH1 3HP e-mail: [email protected] Tel: +44 0191 334 6107 http://etheses.dur.ac.uk me91 In the name of Allah, the Gracious, the Merciful >° 9 43'' 0' eji e' e e> igo4 U61 J CO J: lic 6..ý v Lo ý , ý.,, "ý J ýs ýºý. ur ý,r11 Lýi is' ý9r ZU LZJE rju No disaster can befall on the earth or in your souls but it is in a book before We bring it into being; that is easy for Allah. In order that you may not grieve for what has escaped you, nor be exultant at what He has given you; and Allah does not love any prideful boaster. -
Messier Objects
Messier Objects From the Stocker Astroscience Center at Florida International University Miami Florida The Messier Project Main contributors: • Daniel Puentes • Steven Revesz • Bobby Martinez Charles Messier • Gabriel Salazar • Riya Gandhi • Dr. James Webb – Director, Stocker Astroscience center • All images reduced and combined using MIRA image processing software. (Mirametrics) What are Messier Objects? • Messier objects are a list of astronomical sources compiled by Charles Messier, an 18th and early 19th century astronomer. He created a list of distracting objects to avoid while comet hunting. This list now contains over 110 objects, many of which are the most famous astronomical bodies known. The list contains planetary nebula, star clusters, and other galaxies. - Bobby Martinez The Telescope The telescope used to take these images is an Astronomical Consultants and Equipment (ACE) 24- inch (0.61-meter) Ritchey-Chretien reflecting telescope. It has a focal ratio of F6.2 and is supported on a structure independent of the building that houses it. It is equipped with a Finger Lakes 1kx1k CCD camera cooled to -30o C at the Cassegrain focus. It is equipped with dual filter wheels, the first containing UBVRI scientific filters and the second RGBL color filters. Messier 1 Found 6,500 light years away in the constellation of Taurus, the Crab Nebula (known as M1) is a supernova remnant. The original supernova that formed the crab nebula was observed by Chinese, Japanese and Arab astronomers in 1054 AD as an incredibly bright “Guest star” which was visible for over twenty-two months. The supernova that produced the Crab Nebula is thought to have been an evolved star roughly ten times more massive than the Sun. -
Naming the Extrasolar Planets
Naming the extrasolar planets W. Lyra Max Planck Institute for Astronomy, K¨onigstuhl 17, 69177, Heidelberg, Germany [email protected] Abstract and OGLE-TR-182 b, which does not help educators convey the message that these planets are quite similar to Jupiter. Extrasolar planets are not named and are referred to only In stark contrast, the sentence“planet Apollo is a gas giant by their assigned scientific designation. The reason given like Jupiter” is heavily - yet invisibly - coated with Coper- by the IAU to not name the planets is that it is consid- nicanism. ered impractical as planets are expected to be common. I One reason given by the IAU for not considering naming advance some reasons as to why this logic is flawed, and sug- the extrasolar planets is that it is a task deemed impractical. gest names for the 403 extrasolar planet candidates known One source is quoted as having said “if planets are found to as of Oct 2009. The names follow a scheme of association occur very frequently in the Universe, a system of individual with the constellation that the host star pertains to, and names for planets might well rapidly be found equally im- therefore are mostly drawn from Roman-Greek mythology. practicable as it is for stars, as planet discoveries progress.” Other mythologies may also be used given that a suitable 1. This leads to a second argument. It is indeed impractical association is established. to name all stars. But some stars are named nonetheless. In fact, all other classes of astronomical bodies are named. -
Modeling of PMS Ae/Fe Stars Using UV Spectra ,
A&A 456, 1045–1068 (2006) Astronomy DOI: 10.1051/0004-6361:20040269 & c ESO 2006 Astrophysics Modeling of PMS Ae/Fe stars using UV spectra, P. F. C. Blondel1,2 andH.R.E.TjinADjie1 1 Astronomical Institute “Anton Pannekoek”, University of Amsterdam, Kruislaan 403, 1098 SJ Amsterdam, The Netherlands e-mail: [email protected] 2 SARA, Kruislaan 415, 1098 SJ Amsterdam, The Netherlands Received 13 February 2004 / Accepted 13 October 2005 ABSTRACT Context. Spectral classification of PMS Ae/Fe stars, based on visual observations, may lead to ambiguous conclusions. Aims. We aim to reduce these ambiguities by using UV spectra for the classification of these stars, because the rise of the continuum in the UV is highly sensitive to the stellar spectral type of A/F-type stars. Methods. We analyse the low-resolution UV spectra in terms of a 3-component model, that consists of spectra of a central star, of an optically-thick accretion disc, and of a boundary-layer between the disc and star. The disc-component was calculated as a juxtaposition of Planck spectra, while the 2 other components were simulated by the low-resolution UV spectra of well-classified standard stars (taken from the IUE spectral atlases). The hot boundary-layer shows strong similarities to the spectra of late-B type supergiants (see Appendix A). Results. We modeled the low-resolution UV spectra of 37 PMS Ae/Fe stars. Each spectral match provides 8 model parameters: spectral type and luminosity-class of photosphere and boundary-layer, temperature and width of the boundary-layer, disc-inclination and circumstellar extinction. -
69-22,173 MARKOWITZ, Allan Henry, 1941- a STUDY of STARS
This dissertation has been microfilmed exactly u received 6 9 -2 2 ,1 7 3 MARKOWITZ, Allan Henry, 1941- A STUDY OF STARS EXHIBITING COM POSITE SPECTRA. The Ohio State University, Ph.D., 1969 A stron om y University Microfilms, Inc., Ann Arbor, Michigan A STUDY OF STARS EXHIBITING COMPOSITE SPECTRA DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By Allan Henry Markowitz, A.B., M.Sc. ******** The Ohio S ta te U n iv e rsity 1969 Approved by UjiIjl- A dviser Department of Astronomy ACKNOWLEDGMENTS It is a sincere pleasure to thank my adviser, Professor Arne Slettebak, who originally suggested this problem and whose advice and encouragement were indispensable throughout the course of the research. I am also greatly indebted to Professor Philip Keenan for help in classifying certain late-type spectra and to Professor Terry Roark for instructing me in the operation of the Perkins Observatory telescope, I owe a special debt of gratitude to Dr. Carlos Jaschek of the La Plata Observatory for his inspiration, advice, and encourage ment. The Lowell Observatory was generous in providing extra telescope time when the need arose. I wish to particularly thank Dr. John Hall for this and for his interest. I also gratefully acknowledge the assistance of the Perkins Observatory staff. To my wife, Joan, I owe my profound thanks for her devotion and support during the seemingly unending tenure as a student. I am deeply grateful to my mother for her eternal confidence and to my in-laws for their encouragement. -
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A&A 583, A85 (2015) Astronomy DOI: 10.1051/0004-6361/201526795 & c ESO 2015 Astrophysics Reaching the boundary between stellar kinematic groups and very wide binaries III. Sixteen new stars and eight new wide systems in the β Pictoris moving group F. J. Alonso-Floriano1, J. A. Caballero2, M. Cortés-Contreras1,E.Solano2,3, and D. Montes1 1 Departamento de Astrofísica y Ciencias de la Atmósfera, Facultad de Ciencias Físicas, Universidad Complutense de Madrid, 28040 Madrid, Spain e-mail: [email protected] 2 Centro de Astrobiología (CSIC-INTA), ESAC PO box 78, 28691 Villanueva de la Cañada, Madrid, Spain 3 Spanish Virtual Observatory, ESAC PO box 78, 28691 Villanueva de la Cañada, Madrid, Spain Received 19 June 2015 / Accepted 8 August 2015 ABSTRACT Aims. We look for common proper motion companions to stars of the nearby young β Pictoris moving group. Methods. First, we compiled a list of 185 β Pictoris members and candidate members from 35 representative works. Next, we used the Aladin and STILTS virtual observatory tools and the PPMXL proper motion and Washington Double Star catalogues to look for companion candidates. The resulting potential companions were subjects of a dedicated astro-photometric follow-up using public data from all-sky surveys. After discarding 67 sources by proper motion and 31 by colour-magnitude diagrams, we obtained a final list of 36 common proper motion systems. The binding energy of two of them is perhaps too small to be considered physically bound. Results. Of the 36 pairs and multiple systems, eight are new, 16 have only one stellar component previously classified as a β Pictoris member, and three have secondaries at or below the hydrogen-burning limit. -
A Spectroscopic Study of the Scorpio-Centaurus Association
PranllQa. Vol. 7, No.3, 1976, pp 160-\ 80. © Prmted in India. A spectroscopic study of the Scorpio-Centaurus association R RAJAMOHAN Indian Institute of Astrophysics, Bangaiore 560034 MS recehcl 5 April 1976 • I' Abstract. Rotational .... elocities as well as hydrogen and he Jlum Ine I'ntensities of .' have been one hundred. and twelve members of the Scorplo-Centaurus aSSOclatlO~ . b h derived. For stars with M~ < 0'0, the distribution of rotational velocitieS of °lt are SJlnlar the upper Scorplus subgroup and the upper Centaurus-Lupus Su b grou P 1 . I and closely resemble those of the field stars. Stars with M, > O' 0, all of w lie 1 are found in th.e dense upper Scorpius region, rotate much faster than their counter parts amongst field stars, the Pleiades and Alpha-Persei cluster members. The measured equivalent width of H'Y for 77 stars provide a distance nlOd~\U~ of 6·0±0·09 magnitudes for the association. Evolutionary effects in the del1;~e hydrogen line intensities are found between the two subgroups. The hydrogen- me intensities at all spectral types in the upper Centaurus-Lupus subgroup are systematically smaller than thOse of members in the upper Scorpius subgrouP. Analysis of high dispersion spectra of five members of the association y.ield a helium abundance of Nae(N. = 0·096 ± 0 004. Along with data available In the literature, the mean helium abundance of thirteen stars of this association is found to be 0·098 :±: O· 004 by number. For the two main subgroups of this association, we deflve a value of 0 105 ± 0 001 for the upper Centaurus-Lupus group from three stars and 0·096 ± 0·005 for the upper Scorpius group from ten stars. -
![Arxiv:1608.03799V1 [Astro-Ph.SR] 12 Aug 2016 Department of Physics and Astronomy, Graduate School of Science and Engineering, Kagoshima University, 1-21-35](https://docslib.b-cdn.net/cover/6645/arxiv-1608-03799v1-astro-ph-sr-12-aug-2016-department-of-physics-and-astronomy-graduate-school-of-science-and-engineering-kagoshima-university-1-21-35-906645.webp)
Arxiv:1608.03799V1 [Astro-Ph.SR] 12 Aug 2016 Department of Physics and Astronomy, Graduate School of Science and Engineering, Kagoshima University, 1-21-35
Draft version November 15, 2018 Preprint typeset using LATEX style AASTeX6 v. 1.0 FORMATION OF THE UNEQUAL-MASS BINARY PROTOSTARS IN L1551 NE BY ROTATIONALLY-DRIVEN FRAGMENTATION Jeremy Lim Department of Physics, The University of Hong Kong, Pokfulam Road, Hong Kong & Laboratory for Space Research, Faculty of Science, The University of Hong Kong, Pokfulam Road, Hong Kong Tomoyuki Hanawa Center for Frontier Science, Chiba University, Inage-ku, Chiba 263-8522, Japan Paul K. H. Yeung Department of Physics, The University of Hong Kong, Pokfulam Road, Hong Kong Shigehisa Takakuwa arXiv:1608.03799v1 [astro-ph.SR] 12 Aug 2016 Department of Physics and Astronomy, Graduate School of Science and Engineering, Kagoshima University, 1-21-35 Korimoto, Kagoshima, Kagoshima, 890-0065, Japan Tomoaki Matsumoto Faculty of Humanity and Environment, Hosei University, Chiyoda-ku, Tokyo 102-8160, Japan 2 Kazuya Saigo Department of Physical Science, Graduate School of Science, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan ABSTRACT We present observations at 7 mm that fully resolve the two circumstellar disks, and a reanalyses of archival observations at 3.5 cm that resolve along their major axes the two ionized jets, of the class I binary protostellar system L1551 NE. We show that the two circumstellar disks are better fit by a shallow inner and steep outer power-law than a truncated power-law. The two disks have very different transition radii between their inner and outer regions of ∼18.6 AU and ∼8.9 AU respectively. Assuming that they are intrinsically circular and geometrically thin, we find that the two circumstellar disks are parallel with each other and orthogonal in projection to their respective ionized jets. -
Mètodes De Detecció I Anàlisi D'exoplanetes
MÈTODES DE DETECCIÓ I ANÀLISI D’EXOPLANETES Rubén Soussé Villa 2n de Batxillerat Tutora: Dolors Romero IES XXV Olimpíada 13/1/2011 Mètodes de detecció i anàlisi d’exoplanetes . Índex - Introducció ............................................................................................. 5 [ Marc Teòric ] 1. L’Univers ............................................................................................... 6 1.1 Les estrelles .................................................................................. 6 1.1.1 Vida de les estrelles .............................................................. 7 1.1.2 Classes espectrals .................................................................9 1.1.3 Magnitud ........................................................................... 9 1.2 Sistemes planetaris: El Sistema Solar .............................................. 10 1.2.1 Formació ......................................................................... 11 1.2.2 Planetes .......................................................................... 13 2. Planetes extrasolars ............................................................................ 19 2.1 Denominació .............................................................................. 19 2.2 Història dels exoplanetes .............................................................. 20 2.3 Mètodes per detectar-los i saber-ne les característiques ..................... 26 2.3.1 Oscil·lació Doppler ........................................................... 27 2.3.2 Trànsits -
Optical Counterparts of ROSAT X-Ray Sources in Two Selected Fields at Low
Astronomy & Astrophysics manuscript no. sbg˙comsge˙ed c ESO 2018 October 16, 2018 Optical counterparts of ROSAT X-ray sources in two selected fields at low vs. high Galactic latitudes J. Greiner1, G.A. Richter2 1 Max-Planck-Institut f¨ur extraterrestrische Physik, 85740 Garching, Germany 2 Sternwarte Sonneberg, 96515 Sonneberg, Germany Received 14 October 2013 / Accepted 12 August 2014 ABSTRACT Context. The optical identification of large number of X-ray sources such as those from the ROSAT All-Sky Survey is challenging with conventional spectroscopic follow-up observations. Aims. We investigate two ROSAT All-Sky Survey fields of size 10◦× 10◦ each, one at galactic latitude b = 83◦ (26 Com), the other at b = –5◦ (γ Sge), in order to optically identify the majority of sources. Methods. We used optical variability, among other more standard methods, as a means of identifying a large number of ROSAT All- Sky Survey sources. All objects fainter than about 12 mag and brighter than about 17 mag, in or near the error circle of the ROSAT positions, were tested for optical variability on hundreds of archival plates of the Sonneberg field patrol. Results. The present paper contains probable optical identifications of altogether 256 of the 370 ROSAT sources analysed. In partic- ular, we found 126 AGN (some of them may be misclassified CVs), 17 likely clusters of galaxies, 16 eruptive double stars (mostly CVs), 43 chromospherically active stars, 65 stars brighter than about 13 mag, 7 UV Cet stars, 3 semiregular resp. slow irregular variable stars of late spectral type, 2 DA white dwarfs, 1 Am star, 1 supernova remnant and 1 planetary nebula. -
Binocular Challenges
This page intentionally left blank Cosmic Challenge Listing more than 500 sky targets, both near and far, in 187 challenges, this observing guide will test novice astronomers and advanced veterans alike. Its unique mix of Solar System and deep-sky targets will have observers hunting for the Apollo lunar landing sites, searching for satellites orbiting the outermost planets, and exploring hundreds of star clusters, nebulae, distant galaxies, and quasars. Each target object is accompanied by a rating indicating how difficult the object is to find, an in-depth visual description, an illustration showing how the object realistically looks, and a detailed finder chart to help you find each challenge quickly and effectively. The guide introduces objects often overlooked in other observing guides and features targets visible in a variety of conditions, from the inner city to the dark countryside. Challenges are provided for viewing by the naked eye, through binoculars, to the largest backyard telescopes. Philip S. Harrington is the author of eight previous books for the amateur astronomer, including Touring the Universe through Binoculars, Star Ware, and Star Watch. He is also a contributing editor for Astronomy magazine, where he has authored the magazine’s monthly “Binocular Universe” column and “Phil Harrington’s Challenge Objects,” a quarterly online column on Astronomy.com. He is an Adjunct Professor at Dowling College and Suffolk County Community College, New York, where he teaches courses in stellar and planetary astronomy. Cosmic Challenge The Ultimate Observing List for Amateurs PHILIP S. HARRINGTON CAMBRIDGE UNIVERSITY PRESS Cambridge, New York, Melbourne, Madrid, Cape Town, Singapore, Sao˜ Paulo, Delhi, Dubai, Tokyo, Mexico City Cambridge University Press The Edinburgh Building, Cambridge CB2 8RU, UK Published in the United States of America by Cambridge University Press, New York www.cambridge.org Information on this title: www.cambridge.org/9780521899369 C P. -
THE CONSTELLATION LYNX Lynx, Named After the Animal of That Name, Is a Constellation in the Northern Sky That Was Introduced in the 17Th Century by Johannes Hevelius
THE CONSTELLATION LYNX Lynx, named after the animal of that name, is a constellation in the northern sky that was introduced in the 17th century by Johannes Hevelius. This is a faint constellation with its brightest stars forming a zigzag line. The orange giant Alpha Lyncis is the brightest star in the constellation, while the semiregular variable star Y Lyncis is a target for amateur astronomers. Six star systems have been found to contain planets. 6 Lyncis and HD 75898 were discovered to have planets by the Doppler method, while XO-2, XO-4, XO-5 and WASP-13 were found to have planets that were observed as they passed in front of the host star. Within the constellation's borders lie NGC 2419, an unusually remote globular cluster, the galaxy NGC 2770, which has hosted three recent Type Ib supernovae; the distant quasar APM 08279+5255, whose light is magnified and split into multiple images by the gravitational lensing effect of a foreground galaxy; and the Lynx Supercluster, which was the most distant supercluster known at the time of its discovery in 1999. HISTORY Polish astronomer Johannes Hevelius formed the constellation in the 17th century from 19 faint stars that he observed with the unaided eye between the constellations Ursa Major and Auriga. Naming it Lynx because of its faintness, he challenged future stargazers to see it, declaring that only the lynx-eyed (those of good sight) would have been able to recognize it. There is a figure in mythology who might be linked to the constellation’s name.