July 15,1992 TABLE of CONTENTS
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Chromospheric Ca II Emission in Nearby F, G, K, and M Stars1
Chromospheric Ca II emission in Nearby F, G, K, and M stars1 J. T. Wright2, G. W. Marcy2, R. Paul Butler3, S. S. Vogt4 ABSTRACT We present chromospheric Ca II H & K activity measurements, rotation pe- riods and ages for »1200 F-, G-, K-, and M- type main-sequence stars from »18,000 archival spectra taken at Keck and Lick Observatories as a part of the California and Carnegie Planet Search Project. We have calibrated our chromo- spheric S values against the Mount Wilson chromospheric activity data. From 0 these measurements we have calculated median activity levels and derived RHK, stellar ages, and rotation periods from general parameterizations for 1228 stars, »1000 of which have no previously published S values. We also present precise time series of activity measurements for these stars. Subject headings: stars: activity, rotation, chromospheres 1. Introduction The California & Carnegie Planet Search Program has included observations of »2000 late-type main-sequence stars at high spectral resolution as the core of its ongoing survey of bright, nearby stars to ¯nd extrasolar planets through precision radial velocity measurements (e.g., Cumming, Marcy, & Butler 1999; Butler et al. 2003). One source of error in the measured velocities is that due to \photospheric jitter": flows and inhomogeneities on the 1Based on observations obtained at Lick Observatory, which is operated by the University of California, and on observations obtained at the W. M. Keck Observatory, which is operated jointly by the University of California and the California Institute of Technology. The Keck Observatory was made possible by the generous ¯nancial support of the W.M. -
Arxiv:1705.01114V2 [Astro-Ph.SR] 15 Sep 2017 Aucitfor Manuscript E4 Srla O Aaae Rgnmercspeia Ooe N Colores Y Mag
Manuscript for Revista Mexicana de Astronom´ıa y Astrof´ısica (2017) ABSOLUTE Nuv MAGNITUDES OF GAIA DR1 ASTROMETRIC STARS AND A SEARCH FOR HOT COMPANIONS IN NEARBY SYSTEMS Valeri V. Makarov US Naval Observatory, 3450 Massachusetts Ave NW, Washington DC 20392-5420, USA Received: May 2 2017; Accepted: June 23 2017 RESUMEN Se combinan paralajes del Gaia DR1 (TGAS) con magnitudes visuales Nuv del GALEX para obtener magnitudes absolutas Mnuv as´ıcomo un diagrama HR ultravioleta para una muestra de estrellas astrom´etricas. Se deriva un ajuste para la envolvente inferior de la secuencia principal para las 1403 estrellas con distancias < 40 pc, que no tendr´ıan enrojecimiento. Se seleccionan 50 estrellas cercanas con un exceso Nuv considerable. Estas estrellas son principalmente de tipo K tard´ıo y M temprano, frecuentemente asociadas con fuentes de rayos X, y con otras manifestaciones de actividad magn´etica. La muestra puede incluir sistemas con enanas blancas ocultas, estrellas m´as j´ovenes que las Pl´eyades o binarias interactuantes de tipo BY Dra. Se presenta otra muestra de 40 estrellas con paralajes trigonom´etricas precisas y colores Nuv-G m´as azules que 2 mag. Esta´ incluye varias novas, enanas blancas y binarias con subenanas calientes como compa˜neras. ABSTRACT Accurate parallaxes from Gaia DR1 (TGAS) are combined with GALEX vi- sual Nuv magnitudes to produce absolute Mnuv magnitudes and an ultraviolet HR diagram for a large sample of astrometric stars. A functional fit is derived of the lower envelope main sequence of the nearest 1403 stars (distance < 40 pc), which should be reddening-free. -
1.1 RR Lyrae Stars
Universita` degli studi di Roma “Tor Vergata” Facolta` di Scienze Matematiche, Fisiche e Naturali Dottorato di Ricerca in Astronomia XIX ciclo (2003-2006) SELF-CONSISTENT DISTANCE SCALES FOR POPULATION II VARIABLES Marcella Di Criscienzo Coordinator: Supervisors: PROF. R. BUONANNO PROF. R. BUONANNO PROF.SSA F. CAPUTO DOTT.SSA M. MARCONI Vedere il mondo in un granello di sabbia e il cielo in un fiore di campo tenere l’infinito nel palmo della tua mano e l'eternita´ in un ora. (William Blake) ii Dedico questa tesi a: Mamma e Papa´ Sarocchia Giuliana Marcella & Vincenzo Massimo Filippina Caputo Massimo Capaccioli Roberto Buonanno che mi aiutarono a trovare la strada, e a Tommaso che su questa strada ha viaggiato con me per quasi tutto il tempo Contents The scientific project xv 1 Population II variables 1 1.1 RR Lyrae stars 3 1.1.1 Observational properties 4 1.1.2 Evolutionary properties 6 1.1.3 RR Lyrae as standard candles 8 1.1.4 RR Lyrae in Globular Clusters 9 1.2 Population II Cepheids 13 1.2.1 Present status of knowledge 13 2 Some remarks on the pulsation theory and the computational methods 15 2.1 The pulsation cycle: observations 15 2.2 Pulsation mechanisms 17 2.3 Theoretical approches to stellar pulsation 19 2.4 Computational methods 23 3 Updated pulsation models of RR Lyrae and BL Herculis stars 25 3.1 RR Lyrae (Di Criscienzo et al. 2004, ApJ, 612; Marconi et al., 2006, MNRAS, 371) 25 3.1.1 The instability strip 30 3.1.2 Pulsational amplitudes 31 3.1.3 Some important relations for RR Lyrae studies 36 3.1.4 New results in the SDSS filters 39 3.2 BL Herculis stars (Marconi & Di Criscienzo, 2006, A&A, in press) 43 iv REFERENCES 3.2.1 Light curves and pulsation amplitudes 46 3.2.2 The instability strip 48 4 Comparison with observed RR Lyrae stars and Population II Cepheids 51 4.1 RR Lyrae 52 4.1.1 Comparison of models in Johnson-Cousin filters with current ob- servations (Di Criscienzo et al. -
Sacrilege in Dinétah: Native Encounters with Glen Canyon Dam Sonia Dickey
University of New Mexico UNM Digital Repository History ETDs Electronic Theses and Dissertations 8-19-2011 Sacrilege in Dinétah: Native Encounters with Glen Canyon Dam Sonia Dickey Follow this and additional works at: https://digitalrepository.unm.edu/hist_etds Part of the History Commons Recommended Citation Dickey, Sonia. "Sacrilege in Dinétah: Native Encounters with Glen Canyon Dam." (2011). https://digitalrepository.unm.edu/ hist_etds/21 This Dissertation is brought to you for free and open access by the Electronic Theses and Dissertations at UNM Digital Repository. It has been accepted for inclusion in History ETDs by an authorized administrator of UNM Digital Repository. For more information, please contact [email protected]. i SACRILEGE IN DINÉTAH: NATIVE ENCOUNTERS WITH GLEN CANYON DAM BY SONIA L. DICKEY B.A., History, Georgia Southern University, 1998 M.A., History, Georgia Southern University, 2001 DISSERTATION Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy History The University of New Mexico Albuquerque, New Mexico May 2011 ii Acknowledgments Like any large project, this dissertation benefitted from research grants and scholarships. I would like to thank the History Department at the University of New Mexico, the Charles Redd Center for Western Studies at Brigham Young University, and the New Mexico branch of the Daughters of the American Revolution for providing much needed monies that enabled me to research at institutions all over the Intermountain West. I am extremely grateful for the funding opportunities Dr. Tobias Duran and the Center for Regional Studies have given me during my tenure at the University of New Mexico. -
Observer's Guide to Galaxies
Observer’s Guide to Galaxies By Rob Horvat (WSAAG) Mar 2020 This document has evolved from a supplement to Night-Sky Objects for Southern Observers (Night-Sky Objects for short), which became available on the web in 2009. The document has now been split into two, this one being called the Observer’s Guide to Galaxies. The maps have been designed for those interested in locating galaxies by star-hopping around the constellations. However, like Night-Sky Objects, the resource can be used to simply identify interesting galaxies to GOTO. As with Night-Sky Objects, the maps have been designed and oriented for southern observers with the limit of observation being Declination +55 degrees. Facing north, the constellations are inverted so that they are the “right way up”. Facing south, constellations have the usual map orientation. Pages are A4 in size and can be read as a pdf on a computer or tablet. Note on copyright. This document may be freely reproduced without alteration for educational or personal use. Contributed images by WSAAG members remain the property of their authors. Types of Galaxies Spiral (S) galaxies consist of a rotating disk of stars, dust and gas that surround a central bulge or concentration of stars. Bulges often house a central supermassive black hole. Most spiral galaxies have two arms that are sites of ongoing star formation. Arms are brighter than the rest of the disk because of young hot OB class stars. Approx. 2/3 of spiral galaxies have a central bar (SB galaxies). Lenticular (S0) galaxies have a rather formless disk (no obvious spiral arms) with a prominent bulge. -