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NATURE l DECEl\IBEK 28. 1899 J 1 _;. wh. 1m. of Algol 1$ Persei). followed ll\' no loss of accuracy, and thereft•re their puhlicatio:I 1:; . \'enus. Illuminated portion of <lise = o·873· is In :lccordance with th<: decisions of the Con l(r. 6h. sorn. :'llinimum nf Algol (8 . ference of Superintendents of Ephemeride;; held at _l'aris in 1(). t7h. 17m. to 17h. som. OccultatiOn of a Cancn 18<)6, I he constants of aberration, precession, and nutatron have (mag. 4'3) by the moon. _ . lreen altered from the commencement of 1901' ; but, for the con 20 12h. 46m. to 13h. 46m. Occuliatwn of IL\.C. Yenience of oh<en·ers Hill desirint-: to use the Stnl\·e-l'cter's 4006 (mag. 5 71 by the moon. constants, both been inchulcd in the present tables. 21. 1 1 h. 22m. to 12h. 26m. OccultatH>n of '/ "l'Ot•t:I.AR ,. FOR DECE:l!IIER. · -The issue of \"irnini< (mog. 57) by the moon. l'opu!ar Ash·oiiOIII)' for this month contain>, among much -J? ' ISh 3sm. to I6h. 45•11 . Occuliation cf H . .-\.C. generally interesting matter, two useful :lrticlcs by _Profs. II. C. 4722 mag. 5 ·s). \Yilsun and \V. II. Pickering. The former descnbcs a photo 2(}, 1h. Conjunction of Jupiter and the moon graph of the nebula of Andromeda obtained by at Coodsell (Jupiler z ' 3' i'l.). Observatory, the 8-inch Clarke refractor, wrth an exposure I ;h 40n1. of Jupiter'.; Sat. Ill. of twell'e hours given on three nights. -
The Axis Is Nearly Perpendicular to the Orbital Plane ; (2) the Sense Is the Same As That of the Revolution ; (3) the Period Is Longer Than That of the Revolution
No. 7.] 247 75. An Explanation of the Periodic Variable Stars. By Kiyotsugu HIRAYAMA, M.I.A. Astronomical Observatory, Azabu, Tokyo. (Comm. July 13, 1931.) The binary hypotheses, initially proposed to explain the periodic variable stars, were defective. The pulsation theory seemed more promising ; but even this is disappointing in explaining the varieties and the minor details, of the phenomena. The following explanation ,1) although qualitative, seems satisfactory for those. The hypothesis is based on the capture theory of the stars,2) recently proposed by the writer, and is inconsistent with the fission theory. Cepheid Variables. The Cepheid variable is supposed to be a contact system of a giant star and a dwarf star which is almost dark. The relative orbit is supposed to be nearly circular, in accordance with the general tendency of the binary stars. For the rotation of the primary, the following qualifications are made : (1) the axis is nearly perpendicular to the orbital plane ; (2) the sense is the same as that of the revolution ; (3) the period is longer than that of the revolution. No assumption is made for the rotation of the companion, although the libration is very probable. Taking as a model, the stars of spherical form of the masses 10 and 1 solar units, and the period of revolution, 0.02 year, the mean distance comes out as 0.16 astronomical unit, and the velocitiesrelative to the centre of gravity, as 22.3 and 223.5 km sec-1. As a consequence of the relative motion of the companion, a trail, or an abrasion, so to speak, is left on the surface of the primary, which may be recovered as the time goes on. -
Binocular Universe: You're My Hero! December 2010
Binocular Universe: You're My Hero! December 2010 Phil Harrington on't you just love a happy ending? I know I do. Picture this. Princess Andromeda, a helpless damsel in distress, chained to a rock as a ferocious D sea monster loomed nearby. Just when all appeared lost, our hero -- Perseus! -- plunges out of the sky, kills the monster, and sweeps up our maiden in his arms. Together, they fly off into the sunset on his winged horse to live happily ever after. Such is the stuff of myths and legends. That story, the legend of Perseus and Andromeda, was recounted in last month's column when we visited some binocular targets within the constellation Cassiopeia. In mythology, Queen Cassiopeia was Andromeda's mother, and the cause for her peril in the first place. Left: Autumn star map from Star Watch by Phil Harrington Above: Finder chart for this month's Binocular Universe. Chart adapted from Touring the Universe through Binoculars Atlas (TUBA), www.philharrington.net/tuba.htm This month, we return to the scene of the rescue, to our hero, Perseus. He stands in our sky to the east of Cassiopeia and Andromeda, should the Queen's bragging get her daughter into hot water again. The constellation's brightest star, Mirfak (Alpha [α] Persei), lies about two-thirds of the way along a line that stretches from Pegasus to the bright star Capella in Auriga. Shining at magnitude +1.8, Mirfak is classified as a class F5 white supergiant. It radiates some 5,000 times the energy of our Sun and has a diameter 62 times larger. -
Wynyard Planetarium & Observatory a Autumn Observing Notes
Wynyard Planetarium & Observatory A Autumn Observing Notes Wynyard Planetarium & Observatory PUBLIC OBSERVING – Autumn Tour of the Sky with the Naked Eye CASSIOPEIA Look for the ‘W’ 4 shape 3 Polaris URSA MINOR Notice how the constellations swing around Polaris during the night Pherkad Kochab Is Kochab orange compared 2 to Polaris? Pointers Is Dubhe Dubhe yellowish compared to Merak? 1 Merak THE PLOUGH Figure 1: Sketch of the northern sky in autumn. © Rob Peeling, CaDAS, 2007 version 1.2 Wynyard Planetarium & Observatory PUBLIC OBSERVING – Autumn North 1. On leaving the planetarium, turn around and look northwards over the roof of the building. Close to the horizon is a group of stars like the outline of a saucepan with the handle stretching to your left. This is the Plough (also called the Big Dipper) and is part of the constellation Ursa Major, the Great Bear. The two right-hand stars are called the Pointers. Can you tell that the higher of the two, Dubhe is slightly yellowish compared to the lower, Merak? Check with binoculars. Not all stars are white. The colour shows that Dubhe is cooler than Merak in the same way that red-hot is cooler than white- hot. 2. Use the Pointers to guide you upwards to the next bright star. This is Polaris, the Pole (or North) Star. Note that it is not the brightest star in the sky, a common misconception. Below and to the left are two prominent but fainter stars. These are Kochab and Pherkad, the Guardians of the Pole. Look carefully and you will notice that Kochab is slightly orange when compared to Polaris. -
Proper Motion Surveys of the Young Open Clusters Alpha Persei and the Pleiades
A&A 416, 125–136 (2004) Astronomy DOI: 10.1051/0004-6361:20034238 & c ESO 2004 Astrophysics Proper motion surveys of the young open clusters Alpha Persei and the Pleiades N. R. Deacon and N. C. Hambly Institute for Astronomy, University of Edinburgh, Blackford Hill, Edinburgh EH9 3HJ, UK Received 28 August 2003 / Accepted 28 October 2003 Abstract. In this paper we present surveys of two open clusters using photometry and accurate astrometry from the SuperCOSMOS microdensitometer. These use plates taken by the Palomar Oschin Schmidt Telescope giving a wide field (5◦ from the cluster centre in both cases), accurate positions and a long time baseline for the proper motions. Distribution functions are fitted to proper motion vector point diagrams yielding formal membership probabilities. Luminosity and mass functions are then produced along with a catalogue of high probability members. Background star contamination limited the depth of the study of Alpha Per to R = 18. Due to this the mass function found for this cluster could only be fitted with a power ξ = −α α = . +0.14 law ( (m) m ) with 0 86−0.19. However with the better seperation of the Pleiades’ cluster proper motion from the field population results were obtained down to R = 21. As the mass function produced for this cluster extends to lower masses it is possible to see the gradient becoming increasingly shallow. This mass function is well fitted by a log normal distribution. Key words. astrometry – stars: low mass, brown dwarfs – Galaxy: open clusters and associations: individual: Alpha Per, Pleiades 1. Introduction Most recently Barrado y Navascu´es et al. -
The Planets for 1955 24 Eclipses, 1955 ------29 the Sky and Astronomical Phenomena Month by Month - - 30 Phenomena of Jupiter’S S a Te Llite S
THE OBSERVER’S HANDBOOK FOR 1955 PUBLISHED BY The Royal Astronomical Society of Canada C. A. C H A N T, E d ito r RUTH J. NORTHCOTT, A s s is t a n t E d ito r DAVID DUNLAP OBSERVATORY FORTY-SEVENTH YEAR OF PUBLICATION P r i c e 50 C e n t s TORONTO 13 Ross S t r e e t Printed for th e Society By the University of Toronto Press THE ROYAL ASTRONOMICAL SOCIETY OF CANADA The Society was incorporated in 1890 as The Astronomical and Physical Society of Toronto, assuming its present name in 1903. For many years the Toronto organization existed alone, but now the Society is national in extent, having active Centres in Montreal and Quebec, P.Q.; Ottawa, Toronto, Hamilton, London, and Windsor, Ontario; Winnipeg, Man.; Saskatoon, Sask.; Edmonton, Alta.; Vancouver and Victoria, B.C. As well as nearly 1000 members of these Canadian Centres, there are nearly 400 members not attached to any Centre, mostly resident in other nations, while some 200 additional institutions or persons are on the regular mailing list of our publications. The Society publishes a bi-monthly J o u r n a l and a yearly O b s e r v e r ’s H a n d b o o k . Single copies of the J o u r n a l are 50 cents, and of the H a n d b o o k , 50 cents. Membership is open to anyone interested in astronomy. Annual dues, $3.00; life membership, $40.00. -
Keck Spectra of Brown Dwarf Candidates and a Precise
TABLE 1 Summary of Optical Imaging for Alpha Persei Telescope Area Covered Limiting Magnitude (sq.degrees) (R/I) CWRU Schmidt 3.2 21.5/20.5 MHO 1.2m 1.1 22.0/20.7 KPNO 0.9m 0.5 21.5/20.5 KPNO 4.0m 1.3 22.4/21.0 KPNO 4.0m a (2.5) ≈ 24/≈ 23 aBouvier et al. (1999) TABLE 2 Photometry of Alpha Persei Stars Star α(J2000) δ(J2000) Ic R − Ic K Ic − K AP300 3 17 27.6 49 36 53.0 17.85 2.18 14.62 3.23 AP301 3 18 09.2 49 25 19.0 17.75 2.22 14.14 3.61 AP302 3 19 08.4 48 43 48.5 17.63 2.08 ······ AP303 3 19 10.9 48 42 20.0 16.98 1.88 ······ AP304 3 19 13.2 48 31 55.0 18.83 2.40 ······ AP305 3 19 21.7 49 23 32.0 18.48 2.34 ······ AP306 3 19 41.8 50 30 42.0 18.40 2.34 14.9 3.5 AP307 3 20 20.9 48 01 05.0 17.08 2.01 ······ AP308 3 20 59.7 48 18 37.0 16.71 1.89 ······ AP309 3 22 40.6 48 00 36.0 16.57 1.88 ······ AP275 a 3 23 03.3 48 53 07.0 17.25 2.20 ······ AP310 3 23 04.7 48 16 13.0 17.80 2.33 14.55 3.25 AP311 3 23 08.4 48 04 52.5 17.70 2.12 14.30 3.40 AP312 3 23 14.8 48 11 56.0 18.60 2.41 15.21 3.39 AP313 3 24 08.1 48 48 30.0 17.55 2.13 ······ AP314 3 25 19.6 49 17 58.0 18.20 2.26 15.15 3.05 AP315 3 26 34.5 49 07 46.0 18.20 2.34 14.80 3.40 arXiv:astro-ph/9909207v2 15 Sep 1999 AP316 3 27 01.3 49 14 40.0 17.75 2.18 14.48 3.27 AP317 3 28 06.0 48 45 13.5 17.85 2.29 15.0 2.85 AP318 3 30 42.5 48 21 27.0 17.45 2.16 14.10 3.35 AP319 3 31 03.2 49 02 58.0 16.89 1.95 ······ AP320 3 31 25.3 49 02 52.0 16.79 1.90 ······ AP321 3 32 18.7 49 32 18.0 17.75 2.20 ······ AP322 3 33 08.3 49 37 56.5 17.60 2.14 14.57 3.03 AP323 3 33 20.7 48 45 51.0 17.50 2.13 14.33 3.17 AP324 3 33 48.2 48 52 30.5 18.10 2.36 14.68 3.42 AP325 3 35 47.2 49 17 43.0 17.65 2.30 14.14 3.51 AP326 3 38 55.2 48 57 31.0 18.70 2.40 15.09 3.61 aAP275 is from Prosser (1994). -
Deep-Sky Objects - Autumn Collection an Addition To: Explore the Universe Observing Certificate Third Edition RASC NW Cons Object Mag
Deep-Sky Objects - Autumn Collection An addition to: Explore the Universe Observing Certificate Third Edition RASC NW Cons Object Mag. PSA Observation Notes: Chart RA Dec Chart 1) Date Time 2 Equipment) 3) Notes # Observing Notes # Sgr M24 The Sagittarias Star Cloud 1. Mag 4.60 RA 18:16.5 Dec -18:50 Distance: 10.0 2. (kly)Star cloud, 95’ x 35’, Small Sagittarius star cloud 3. lies a little over 7 degrees north of teapot lid. Look for 7,8 dark Lanes! Wealth of stars. M24 has dark nebula 67 (interstellar dust – often visible in the infrared (cooler radiation)). Barnard 92 – near the edge northwest – oval in shape. Ref: Celestial Sampler Floating on Cloud 24, p.112 Sgr M18 - 1. RA 18 19.9, Dec -17.08 Distance: 4.9 (kly) 2. Lies less than 1deg above the northern edge of M24. 3 8 Often bypassed by showy neighbours, it is visible as a 67 small hazy patch. Note it's much closer (1/2 the distance) as compared to M24 (10kly) Sgr M17 (Swan Nebula) and M16 – HII region 1. Nebula and Open Clusters 2. 8 67 M17 Wikipedia 3. Ref: Celestial Sampler p. 113 Sct M11 Wild Duck Cluster 5.80 1. 18:51.1 -06:16 Distance: 6.0 (kly) 2. Open cluster, 13’, You can find the “wild duck” cluster, 3. as Admiral Smyth called it, nearly three degrees west of 67 8 Aquila’s beak lying in one of the densest parts of the summer Milky Way: the Scutum Star Cloud. 9 64 10 Vul M27 Dumbbell Nebula 1. -
Milan Dimitrijevic Avgust.Qxd
1. M. Platiša, M. Popović, M. Dimitrijević, N. Konjević: 1975, Z. Fur Natur- forsch. 30a, 212 [A 1].* 1. Griem, H. R.: 1975, Stark Broadening, Adv. Atom. Molec. Phys. 11, 331. 2. Platiša, M., Popović, M. V., Konjević, N.: 1975, Stark broadening of O II and O III lines, Astron. Astrophys. 45, 325. 3. Konjević, N., Wiese, W. L.: 1976, Experimental Stark widths and shifts for non-hydrogenic spectral lines of ionized atoms, J. Phys. Chem. Ref. Data 5, 259. 4. Hey, J. D.: 1977, On the Stark broadening of isolated lines of F (II) and Cl (III) by plasmas, JQSRT 18, 649. 5. Hey, J. D.: 1977, Estimates of Stark broadening of some Ar III and Ar IV lines, JQSRT 17, 729. 6. Hey, J. D.: Breger, P.: 1980, Stark broadening of isolated lines emitted by singly - ionized tin, JQSRT 23, 311. 7. Hey, J. D.: Breger, P.: 1981, Stark broadening of isolated ion lines by plas- mas: Application of theory, in Spectral Line Shapes I, ed. B. Wende, W. de Gruyter, 201. 8. Сыркин, М. И.: 1981, Расчеты электронного уширения спектральных линий в теории оптических свойств плазмы, Опт. Спектроск. 51, 778. 9. Wiese, W. L., Konjević, N.: 1982, Regularities and similarities in plasma broadened spectral line widths (Stark widths), JQSRT 28, 185. 10. Konjević, N., Pittman, T. P.: 1986, Stark broadening of spectral lines of ho- mologous, doubly ionized inert gases, JQSRT 35, 473. 11. Konjević, N., Pittman, T. P.: 1987, Stark broadening of spectral lines of ho- mologous, doubly - ionized inert gases, JQSRT 37, 311. 12. Бабин, С. -
The Ages of Early-Type Stars: Str\" Omgren Photometric Methods
Draft version September 10, 2018 Preprint typeset using LATEX style emulateapj v. 5/2/11 THE AGES OF EARLY-TYPE STARS: STROMGREN¨ PHOTOMETRIC METHODS CALIBRATED, VALIDATED, TESTED, AND APPLIED TO HOSTS AND PROSPECTIVE HOSTS OF DIRECTLY IMAGED EXOPLANETS Trevor J. David1,2 and Lynne A. Hillenbrand1 1Department of Astronomy; MC 249-17; California Institute of Technology; Pasadena, CA 91125, USA; tjd,[email protected] Draft version September 10, 2018 ABSTRACT Age determination is undertaken for nearby early-type (BAF) stars, which constitute attractive targets for high-contrast debris disk and planet imaging surveys. Our analysis sequence consists of: acquisition of uvbyβ photometry from catalogs, correction for the effects of extinction, interpolation of the photometry onto model atmosphere grids from which atmospheric parameters are determined, and finally, comparison to the theoretical isochrones from pre-main sequence through post-main sequence stellar evolution models, accounting for the effects of stellar rotation. We calibrate and validate our methods at the atmospheric parameter stage by comparing our results to fundamentally determined Teff and log g values. We validate and test our methods at the evolutionary model stage by comparing our results on ages to the accepted ages of several benchmark open clusters (IC 2602, α Persei, Pleiades, Hyades). Finally, we apply our methods to estimate stellar ages for 3493 field stars, including several with directly imaged exoplanet candidates. Subject headings: stars: early-type |evolution |fundamental parameters |Hertzsprung-Russell and C-M diagrams |planetary systems |astronomical databases: catalogs 1. INTRODUCTION planet formation efficiency to stellar mass. The claim is In contrast to other fundamental stellar parameters that while 14% of A stars have one or more > 1MJupiter companions∼ at <5 AU, only 2% of M stars do (Johnson such as mass, radius, and angular momentum { that for ∼ certain well-studied stars and stellar systems can be an- et al. -
Algol Türü Örten Çift Yildizlarin Işikölçüm Ve Tayf Gözlemleri
XVI. Ulusal Astronomi Kongresi ve V. Ulusal Öğrenci Astronomi Kongresi-2008, Çanakkale ALGOL TÜRÜ ÖRTEN ÇİFT YILDIZLARIN IŞIKÖLÇÜM VE TAYF GÖZLEMLERİ C. İBANOĞLU, S. EVREN, G. TAŞ, Ö. ÇAKIRLI, Z. BOZKURT, M. AFŞAR, E.SİPAHİ, H. A. DAL, O. ÖZDARCAN, D. Z. ÇAMURDAN, M. ÇAMURDAN Ege Üniversitesi, Astronomi ve Uzay Bilimleri Bölümü, 35100 Bornova İzmir Özet: Hipparcos uydusu ile keşfedilen 13 örten çift yıldızın ışıkölçüm ve tayf gözlemleri yapılmıştır. Örten çift olduğu daha önceden bilinen zonklayan yıldız bileşenli HD 172189 ve kuvvetli salma çizgileri gösteren disk yapılı AW Peg yıldızı da listeye alınmıştır. AW Peg’in ışıkölçüm verileri daha önce elde edildiğinden yalnızca tayf gözlemleri yapılmıştır. Seçilen yıldızlardan 14’ünün ışıkölçüm ve tayf gözlemleri iki yıl gibi kısa bir sürede bitirilmiştir. CP Psc sönük olduğundan tayfı alınamamıştır. Işıkölçüm gözlemleri Ege Üniversitesi Gözlemevi’nin 48, 40 ve 35 cm’lik teleskopları ile yapılmıştır. Üç kanallı hızlı ışıkölçeri, CCD kameralar ve UBV süzgeçleri kullanılmıştır. Tayf gözlemler Catania Astrofizik Gözlemevi’nin 91 cm, TÜBİTAK TUG’un 150 ve David Dunlap Gözlemevi’nin 188 cm’lik teleskopları ile yapılmıştır. UBV ışıkölçümleri standart düzeneğe dönüştürülmüş, renk- renk diyagramları ve yıldızlararası ortamın etkisinden bağımsız geniş-band Q-parametresi kullanılarak E(B-V) ve baş yıldızın etkin sıcaklığı Te belirlenmiştir. Bu sıcaklık yıldızın tayfı ile karşılaştırılmıştır. Işık eğrilerinin analizinde temel öğe olan baş yıldızın etkin sıcaklığı duyarlı olarak bulunduktan sonra ışık eğrileri ve dikine hız verileri ortak olarak analiz edilmiş, bileşen yıldızların temel öğeleri kütle, yarıçap, sıcaklık ve ışıtmaları bulumuştur. Yıldızların bulunan salt öğeleri kuramsal modellerle karşılaştırılmış, evrim durumları ortaya çıkartılmıştır. Bileşenlerin ışınımsal özellikleri ve yıldızlararası kızıllaşma değerleri kullanılarak uzaklıklar hesaplanmıştır. -
1. Introduction
THE ASTROPHYSICAL JOURNAL, 525:420È433, 1999 November 1 ( 1999. The American Astronomical Society. All rights reserved. Printed in U.S.A. ULTRAVIOLET AND OPTICAL LINE PROFILE VARIATIONS IN THE SPECTRUM OF v PERSEI D. R. GIES,1 E. KAMBE,2 T. S. JOSEPHS,W.G.BAGNUOLO,JR., Y. J. CHOI,D.GUDEHUS,K.M.GUYTON,3 W. I. HARTKOPF,4,5 J. L. HILDEBRAND,A.B.KAYE,6 B. D. MASON,4,5 R. L. RIDDLE,J.W.SOWERS, N. H. TURNER,7 J. W. WILSON, AND Y. XIONG Center for High Angular Resolution Astronomy, Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30303; gies=chara.gsu.edu, kambe=cc.nda.ac.jp, tammy=chara.gsu.edu, bagnuolo=chara.gsu.edu, phyyjcx=panther.gsu.edu, gudehus=chara.gsu.edu, uskmg=emory.edu, hartkopf=chara.gsu.edu, jlh=chara.gsu.edu, kaye=lanl.gov, bdm=draco.usno.navy.mil, riddle=chara.gsu.edu, sowers=chara.gsu.edu, nils=chara.gsu.edu, wilson=chara.gsu.edu, ying=chara.gsu.edu Received 1998 October 27; accepted 1999 June 17 ABSTRACT The rapid variable star, v Per (B0.5 IVÈIII), displays the largest amplitude proÐle Ñuctuations known among the growing number of massive, spectrum-variable stars. Here we present an analysis of a contin- uous 5 day run of IUE UV spectroscopy, and we show for the Ðrst time that the systematic, blue-to-red moving patterns observed in high-quality optical spectra are also present in the UV photospheric lines. We present cross-correlation functions of the individual spectra with that of a narrow-lined standard that produce a high signal-to-noise ratio representation of the blue-to-red moving bump patterns found in individual lines.