Parallaxes and Proper Motions for 20 Open Clusters As Based on the New
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100Th Anniversary Edition
Volume 40 Number 1 JAAVSO 2012 The Journal of the American Association of Variable Star Observers Part B of two parts pages 267–608 100th Anniversary Edition • History • Associations • Science • Review Papers 49 Bay State Road Cambridge, MA 02138 U. S. A. The Journal of the American Association of Variable Star Observers Editor Editorial Board John R. Percy Geoffrey C. Clayton Matthew R. Templeton University of Toronto Louisiana State University AAVSO Toronto, Ontario, Canada Baton Rouge, Louisiana Douglas L. Welch Associate Editor Edward F. Guinan McMaster University Elizabeth O. Waagen Villanova University Hamilton, Ontario, Canada Villanova, Pennsylvania Assistant Editor David B. Williams Matthew R. Templeton Pamela Kilmartin Whitestown, Indiana University of Canterbury Production Editor Christchurch, New Zealand Thomas R. Williams Michael Saladyga Houston, Texas Laszlo Kiss Konkoly Observatory Lee Anne Willson Budapest, Hungary Iowa State University Ames, Iowa Paula Szkody University of Washington Seattle, Washington The Council of the American Association of Variable Star Observers 2011–2012 Director Arne A. Henden President Mario E. Motta Past President Jaime R. García 1st Vice President Jennifer Sokoloski Secretary Gary Walker Treasurer Gary W. Billings (term ended May 2012) Treasurer Timothy Hager Councilors Edward F. Guinan John Martin Roger S. Kolman Donn R. Starkey Chryssa Kouveliotou Robert J. Stine Arlo U. Landolt David G. Turner ISSN 0271-9053 JAAVSO The Journal of The American Association of Variable Star Observers Volume 40 Number 1 2012 Part B of two parts: pages 267–608 100th Anniversary Edition History Associations Science Review Papers 49 Bay State Road Cambridge, MA 02138 ISSN 0271-9053 U. S. A. -
Search for Neutrinos from Flaring Blazars
Julius-Maximilians-Universität Würzburg Lehrstuhl für Physik und Astronomie Masterarbeit vorgelegt von Michael Kreter Search for neutrinos from flaring blazars - A time dependent point source analysis - Verantwortlicher Hochschullehrer: Prof. Dr. Matthias Kadler Zweitgutachter: Prof. Dr. Gisela Anton Abgabetermin: 21. August 2015 Abstract Active galactic nuclei (AGN) are one of the most fascinating astrophysical objects in the universe. While they emit photons over the whole electromagnetic spectrum, AGN are also promising candidates to be the sources of the recently discovered high-energy extraterrestrial neutrino flux. ANTARES (Astronomy with a Neutrino Telescope and Abyss Environment RESearch) is a large volume deep-sea water Cherenkov telescope in the Mediterranean Sea located 42 km from Toulon in France. Is is optimized for the detection of muons from high-energetic neu- trinos, which can be produced in the atmosphere or by extraterrestrial accelerators. As the ANTARES detector is optimized for up-going muons, this means that it is “looking down- wards” through the Earth. Thus, neutrino telescopes located on the northern hemisphere are most sensitive to the observation of southern astronomical objects. The TANAMI program (Tracking Active Galactic Nuclei with Austral Milliarcsecond Interfer- ometry) is a multiwavelength program to monitor relativistic jets in active galactic nuclei of the southern sky. It consists of a radio Very Long Baseline Interferometry (VLBI) monitoring program, as well as a high-energy multiwavelength program. As theoretical models predict a correlation of γ-ray and neutrino emission generated in the same processes within an AGN jet, the performance of a multi-messenger analysis using γ-ray light-curves could result in a significant decrease of background in a neutrino point source analysis and thus increase the sensitivity of an analysis to a neutrino signal from AGN. -
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. -
Meeting Announcement Astro-Imaging Special Interest
CVAS Executive Committee Pres – Dell Vance - (435) 938-8328 Loaner Scope Coordinator/NSN Coordinator – [email protected] Garrett Smith – [email protected] Vice Pres- Layne Pedersen – (801) 463-1701 Past President, Webmaster, Librarian – [email protected] Tom Westre – (435) 787-6380 [email protected] Treasurer- Brad Kropp - (435) 755-0877 Public Relations – Lyle Johnson - [email protected] Secretary – Dale Hooper - (435) 563-0608 [email protected] Vol. 5 Number 7 March 2018 www.cvas-utahskies.org Meeting Announcement With that in mind, I was able to travel down to Goblin Valley and Arches National Park during Our March meeting will be held on the fourth February. I took my binoculars and my camera Wednesday, March 28, 2018 at 7pm in room 840 along, because these areas are known for their dark of the main BATC campus. We have room 840 skies. It was a couple of days before a new moon so for the rest of this year. Enter on the east side of the the skies should be great. At Arches NP bookshop, I building located at 1301 North 600 West. found a book titled “Photography NIGHT SKY” by Our featured speaker this month is club member Garrett Smith. He will be sharing with us a presentation about the king of planets, Jupiter. Astro-Imaging Special Interest Group The Astro-Imaging SIG will have a kick-off meeting at the Logan Library in the Temple Fork room at 7pm on March 15th. Please contact Tom at 435-787- 6380 if you are interested. The President’s Corner By Dell Vance, CVAS President Jennifer Wu and James Martin. -
Open Clusters with Hipparcos I. Mean Astrometric Parameters N
Open clusters with Hipparcos I. Mean astrometric parameters N. Robichon, Frédéric Arenou, J.-C Mermilliod, C. Turon To cite this version: N. Robichon, Frédéric Arenou, J.-C Mermilliod, C. Turon. Open clusters with Hipparcos I. Mean astrometric parameters. Astronomy and Astrophysics - A&A, EDP Sciences, 1999, 345 (2), pp.471- 484. hal-02053849 HAL Id: hal-02053849 https://hal.archives-ouvertes.fr/hal-02053849 Submitted on 1 Mar 2019 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Astron. Astrophys. 345, 471–484 (1999) ASTRONOMY AND ASTROPHYSICS Open clusters with Hipparcos? I. Mean astrometric parameters N. Robichon1,2, F. Arenou2, J.-C. Mermilliod3, and C. Turon2 1 Sterrewacht Leiden, Postbus 9513, 2300 RA Leiden, The Netherlands 2 Observatoire de Paris, section de Meudon, DASGAL/CNRS URA 335, F-92195 Meudon CEDEX, France (Noel.Robichon, Frederic.Arenou, [email protected]) 3 Institut d’Astronomie de Lausanne, CH-1290 Chavannes des Bois, Switzerland ([email protected]) Received 9 December 1998 / Accepted 19 February 1999 Abstract. New memberships, mean parallaxes and proper mo- absolute position of the main sequences of several open clusters tions of all 9 open clusters closer than 300 pc (except the Hyades) independently of any preliminary knowledge of the chemical and 9 rich clusters between 300 and 500 pc have been computed composition. -
SPITZER/IRAC-MIPS Survey of NGC2451A and B: Debris Disks At
Draft version June 19, 2018 A Preprint typeset using LTEX style emulateapj v. 08/22/09 SPITZER/IRAC-MIPS SURVEY OF NGC2451A AND B: DEBRIS DISKS AT 50-80 MILLION YEARS Zoltan Balog1 Steward Observatory, University of Arizona, 933 N. Cherry Av. Tucson, AZ, 85721 Laszl´ o´ L. Kiss Sydney Institute for Astronomy, School of Physics A28, University of Sydney, NSW 2006, Australia Jozsef´ Vinko´ Dept. of Optics and Quantum Electronics, University of Szeged, H-6720, Szeged, Hungary G. H. Rieke, James Muzerolle, Andras´ Gasp´ ar,´ Erick T. Young Steward Observatory, University of Arizona, 933 N. Cherry Av. Tucson, AZ, 85721 Nadya Gorlova Department of Astronomy, University of Florida, Gainesville, FL 32611-2055. Draft version June 19, 2018 ABSTRACT We present a Spitzer IRAC and MIPS survey of NGC 2451 A and B, two open clusters in the 50-80 Myr age range. We complement these data with extensive ground-based photometry and spectroscopy to identify the cluster members in the Spitzer survey field. We find only two members with 8 micron excesses. The incidence of excesses at 24 microns is much higher, 11 of 31 solar-like stars and 1 of 7 early-type (A) stars. This work nearly completes the debris disk surveys with Spitzer of clusters in the 30-130 Myr range. This range is of interest because it is when large planetesimal collisions may have still been relatively common (as indicated by the one that led to the formation of the Moon during this period of the evolution of the Solar System). We review the full set of surveys and find that there are only three possible cases out of about 250 roughly solar-mass stars where very large excesses suggest that such collisions have occurred recently. -
The Spiral Pattern Rotation Speed of the Galaxy and the Corotation Radius
MNRAS 000, 1–14 (2015) Preprint 21 May 2019 Compiled using MNRAS LATEX style file v3.0 The spiral pattern rotation speed of the Galaxy and the corotation radius with GAIA DR2 W. S. Dias,1⋆ H. Monteiro,1, J. R. D. L´epine2 , and D. A. Barros3 1UNIFEI, Instituto de F´ısica e Qu´ımica, Universidade Federal de Itajub´a, Av. BPS 1303 Pinheirinho, 37500-903 Itajub´a, MG, Brazil 2Universidade de S˜ao Paulo, Instituto de Astronomia, Geof´ısica e Ciˆencias Atmosf´ericas, S˜ao Paulo - SP, Brazil 3Rua Sessenta e Trˆes, 125, Rio Doce, Olinda, 53090-393 Pernambuco, Brazil Accepted 2019 April 24. Received 2019 April 22; in original form 2019 March 20 ABSTRACT In this work we revisit the issue of the rotation speed of the spiral arms and the location of the corotation radius of our Galaxy. This research was performed using ho- mogeneous data set of young open clusters (age < 50 Myr) determined from Gaia DR2 data. The stellar astrometric membership were determined using proper motions and parallaxes, taking into account the full covariance matrix. The distance, age, reddening and metallicity of the clusters were determined by our non subjective multidimensional global optimization tool to fit theoretical isochrones to Gaia DR2 photometric data. The rotation speed of the arms is obtained from the relation between age and angu- lar distance of the birthplace of the clusters to the present-day position of the arms. Using the clusters belonging to the Sagittarius-Carina, Local and Perseus arms, and −1 adopting the Galactic parameters R0 = 8.3 kpc and V0 = 240 kms , we determine a pattern speed of 28.2 ± 2.1 kms−1 kpc−1, with no difference between the arms. -
Arxiv:1801.10042V2 [Astro-Ph.GA] 8 Feb 2018
Astronomy & Astrophysics manuscript no. article_arXiv ©ESO 2018 February 9, 2018 Characterising open clusters in the solar neighbourhood with the Tycho-Gaia Astrometric Solution T. Cantat-Gaudin1, A. Vallenari1, R. Sordo1, F. Pensabene1; 2, A. Krone-Martins3, A. Moitinho3, C. Jordi4, L. Casamiquela4, L. Balaguer-Núnez4, C. Soubiran5, and N. Brouillet5 1 INAF-Osservatorio Astronomico di Padova, vicolo Osservatorio 5, 35122 Padova, Italy 2 Dipartimento di Fisica e Astronomia, Università di Padova, vicolo Osservatorio 3, 35122 Padova, Italy 3 SIM, Faculdade de Ciências, Universidade de Lisboa, Ed. C8, Campo Grande, P-1749-016 Lisboa, Portugal 4 Institut de Ciències del Cosmos, Universitat de Barcelona (IEEC-UB), Martí i Franquès 1, E-08028 Barcelona, Spain 5 Laboratoire d’Astrophysique de Bordeaux, Univ. Bordeaux, CNRS, UMR 5804, 33615 Pessac, France Received date / Accepted date ABSTRACT Context. The Tycho-Gaia Astrometric Solution (TGAS) subset of the first Gaia catalogue contains an unprecedented sample of proper motions and parallaxes for two million stars brighter than G ∼ 12 mag. Aims. We take advantage of the full astrometric solution available for those stars to identify the members of known open clusters and compute mean cluster parameters using either TGAS or the fourth U.S. Naval Observatory CCD Astrograph Catalog (UCAC4) proper motions, and TGAS parallaxes. Methods. We apply an unsupervised membership assignment procedure to select high probability cluster members, we use a Bayesian/Markov Chain Monte Carlo technique to fit stellar isochrones to the observed 2MASS JHKS magnitudes of the member stars and derive cluster parameters (age, metallicity, extinction, distance modulus), and we combine TGAS data with spectroscopic radial velocities to compute full Galactic orbits. -
An X-Ray Study of the Open Clusters NGC 2451 a and B?,??
A&A 402, 571–586 (2003) Astronomy DOI: 10.1051/0004-6361:20030268 & c ESO 2003 Astrophysics An X-ray study of the open clusters NGC 2451 A and B?;?? M. H¨unsch1,C.Weidner1, and J. H. M. M. Schmitt2 1 Institut f¨ur Theoretische Physik und Astrophysik, Universit¨at Kiel, Olshausenstraße 40, 24118 Kiel, Germany 2 Hamburger Sternwarte, Universit¨at Hamburg, Gojenbergsweg 112, 21029 Hamburg, Germany Received 8 November 2002 / Accepted 15 January 2003 Abstract. We have conducted a detailed study of the object NGC 2451, which actually consists of two different open clusters A and B along the same line of sight at 206 pc and 370 pc distance, respectively. Although belonging to the nearest clusters, they have not been much investigated until present due to strong contamination by field stars. ROSAT X-ray observations and optical UBVR photometry are used to identify cluster members by means of X-ray emission and colour-magnitude diagrams. The identified stars concentrate nicely around the expected main sequences in the colour-magnitude diagram at the distances derived from astrometric investigations. Altogether, 39 stars are identified as member candidates of the nearer cluster A, 49 stars as member candidates of the more distant cluster B, and 22 faint stars are probably members of either of the two clusters, but due to large errors it is not clear to which one they belong. Further 40 stars identified with X-ray sources are probably non-members. For the first time, the range of known probable cluster members of NGC 2451 A and B has been extended downwards the main sequence to stars of spectral class M. -
032017-Aktuelles-Am-Sternenhimmel
A N T A R E S NÖ AMATEURASTRONOMEN NOE VOLKSSTERNWARTE Michelbach Dorf 62 3074 MICHELBACH NOE VOLKSSTERNWARTE 3074 MICHELBACH Die VOLKSSTERNWARTE im Zentralraum Niederösterreich I see skies of blue and clouds of white the bright blessed day, the dark sacred night and I think to myself what a wonderful world. Louis Armstrong; What a Wonderful World AKTUELLES AM STERNENHIMMEL MÄRZ 2017 Montag, 20.03.2017, 11h 29m MEZ: Frühlingsbeginn. Die Wintersternbilder, am Monatsanfang noch hoch im Zenit, sind am Monatsende in der westlichen Himmelshälfte aufzufinden, die Frühlingssternbilder kommen in der östlichen Himmelshälfte hoch. Der Jahreszeitenwechsel ist auch am Nachthimmel erkennbar. Merkur kann in der Abenddämmerung aufgefunden werden, Venus, am Monatsanfang am Abendhimmel, taucht am Monatsende am Morgenhimmel auf, Mars, nicht besonders auffällig, geht in der ersten Nachthälfte unter, Jupiter wird zum Planeten der gesamten Nacht, der Ringplanet Saturn ist der Planet der zweiten Nachthälfte. INHALT Auf- und Untergangszeiten Sonne und Mond Aktueller Sternenhimmel Fernglasobjekte Planetendaten Sternschnuppenschwärme Vereinsabend 10.03.2017 Sternwarte hat WINTERSPERRE VEREINSABEND 10.03.2017 REFERENT DDr. Thomas Posch THEMA Der neue Welt-Atlas der Lichtverschmutzung Detailinformationen finden Sie in der Rubrik VEREINSABEND. Besucher heißen wir herzlich willkommen! EINTRITT FREI! Die Auf- und Untergangsdaten für alle Himmelsobjekte gelten für die Koordinaten der NOE VOLKSSTERNWARTE 3074 MICHELBACH. Quelle: http://www.calsky.com NOE VOLKSSTERNWARTE 3074 MICHELBACH Michelbach Dorf 62, 3074 Michelbach Seehöhe 640 m NN Geografische Koordinaten UTM-Koordinaten UTMREF-Koordinaten N 48 05 16 - E 015 45 22 33U 556320 E 5326350 N 33 U WP 5632 2635 ANTARES Nö Amateurastronomen | 3100 St.Pölten | I http://www.noe-sternwarte.at | ZVR-Zahl 621010104 DIE SONNE (☉) Sonnenuntergang - SU Dauer etwa 3 – 4 Minuten, bis Sonne vollständig unter dem Horizont verschwunden ist. -
198 9Apj. . .347. .835G the Astrophysical Journal, 347:835-848
.835G The Astrophysical Journal, 347:835-848,1989 December 15 © 1989. The American Astronomical Society. All rights reserved. Printed in U.S.A. .347. 9ApJ. 198 CARBON ISOTOPE RATIOS AND LITHIUM ABUNDANCES IN OPEN CLUSTER GIANTS K ALP ANA KrISHNASWAMY GiLROY1 Department of Astronomy and McDonald Observatory, University of Texas, Austin Received 1989 February 21 ; accepted 1989 June 13 ABSTRACT New high-resolution, high S/N spectra of CN lines at 8000 Â and Li lines at 6707 Â have been obtained for giants m about 20 Galactic open clusters and 12C/13C ratios and Li abundances determined for these stars. The ages of the clusters vary from about 50 million years to 5 billion years, and their turn-off masses vary from 1 M0 to about 6 M0. The ages and turn-off masses were determined by fitting theoretical isochrones to the cluster color-magnitude diagrams. Correlation of the isotope ratio and the Li abundances with the cluster turn-off masses indicates the following: (1) the 12C/13C ratio increases steeply with the turn-off mass until a mass of approximately 2.2 M0 when the ratio levels off abruptly to a value near 26; (2) older clusters with 12 13 turn-off masses lower than about 2.2 M0 in general exhibit C/ C ratios that are considerably lower than the theoretically predicted values while those with larger turn-off masses (M > 2.2 M0) show ratios close to standard predictions; and (3) no strong correlation exists between the Li abundances and the cluster turn-off masses, and the Li abundances in giants are, in general, lower than theoretically predicted values. -