DOCSLIB.ORG

The Initial Conditions and Evolution of Open Clusters by Joseph Mitchell

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Initial Conditions and Evolution of Open Clusters by Joseph Mitchell The Initial Conditions and Evolution of Open Clusters by Joseph Mitchell Converse A dissertation submitted in partial satisfaction of the requirements for the degree of Doctor of Philosophy in Astrophysics in the Graduate Division of the University of California, Berkeley Committee in charge: Doctor Steven Stahler, Co-chair Professor Chris McKee, Co-chair Professor James Graham Professor Michael Manga Fall 2010 The Initial Conditions and Evolution of Open Clusters Copyright 2010 by Joseph Mitchell Converse 1 Abstract The Initial Conditions and Evolution of Open Clusters by Joseph Mitchell Converse Doctor of Philosophy in Astrophysics University of California, Berkeley Doctor Steven Stahler, Co-chair Professor Chris McKee, Co-chair Despite being some of the most familiar objects observed in the sky, much remains unknown about open clusters. The theory of their formation admits many unanswered questions, and the complex dynamics of their evolution remains an extremely difficult problem to address. In this thesis, I present results that both help to constrain formation theories, as well as to shed new understanding on the many physical processes that drive their evolution. Starting with a photometric catalog of a cluster, I employ a maximum likelihood tech- nique to determine the mass distribution of its members, including single stars and both components of binary systems. This method allows me to determine not just the fraction of systems which are binary, but also the typical degree of correlation between the masses of their components. I also examine the spatial distribution of the cluster members. The issue of mass segregation is also addressed, introducing a new method for quantifying it. After quantifying many different properties of the cluster, N-body simulations are used to find the initial state that evolves to most closely match the current cluster. Although a few similar studies have been done in the past, I use a far larger breadth of parameters to compare with the actual data than any previous work. This results in a fairly confident determination of the properties of very young clusters, which any theory of cluster formation will be required to explain. How the cluster evolves from that initial state to the current day and beyond is also examined in detail. These techniques are used to examine two relatively close and well-known examples of open clusters: the Pleiades and the Alpha Persei cluster. In the case of the former, I find in particular that the overall binary fraction is as high as 76%, significantly higher than the accepted field-star result. The primary and secondary masses within binaries are found to be correlated, in the sense that their ratios are closer to unity than under the hypothesis of random pairing. I also find unambiguous evidence of mass segregation within the cluster. Building on these results, I find the original cluster, newly stripped of gas, to have already had a virial radius of 4 pc. This configuration was larger than most observed, embedded clusters. Over time, the cluster expanded further and the central surface density fell by about a factor of two. I attribute both effects to the liberation of energy from 2 tightening binaries of short period. Indeed, the original binary fraction was close to unity. The ancient Pleiades also had significant mass segregation, which persists in the cluster today. In the future, the central density of the Pleiades will continue to fall. For the first few hundred Myr, the cluster as a whole will expand because of dynamical heating by binaries. The expansion process is aided by mass loss through stellar evolution, which weakens the system’s gravitational binding. At later times, the Galactic tidal field begins to heavily deplete the cluster mass. Barring destruction by close passage of a giant molecular cloud, the density falloff will continue for as long as 1 Gyr, by which time most of the cluster mass will have been tidally stripped away by the Galactic field. This same analysis is also applied to Alpha Persei. Here I fist compile the most complete photometric catalog of the system to date. The stellar mass function is found to be weighted more heavily toward higher-mass stars than in the Pleiades. Also in contrast with the Pleiades, I find there to be essentially no mass segregation in the cluster, either today or in its initial state. The binary fraction, however, is found to be quite similar between the two clusters, as high as 70% in Alpha Persei. Once more the initial state is found to be quite large compared to embedded systems. The results of these two clusters together argue strongly the young clusters experience a period of significant expansion associated with the loss of their natal gas. Over time, Alpha Persei will globally expanded as a result of the Galactic tidal field. Dynamical heating by binaries, along with mass loss through stellar evolution, will also inflate the cluster into the future. I predict that Alpha Persei will completely dissolve within the next 300 Myr. Utilizing a series of N-body simulations, I go on to argue that gravitationally bound stellar clusters of modest population evolve very differently from the picture presented by classical dynamical relaxation theory. The system’s most massive stars rapidly sink towards the center and form binary systems. These binaries efficiently heat the cluster, reversing any incipient core contraction and driving a subsequent phase of global expansion. Most previous theoretical studies demonstrating deep and persistent dynamical relaxation have either conflated the process with mass segregation, ignored three-body interactions, or else adopted the artificial assumption that all cluster members are single stars of identical mass. In such a uniform-mass cluster, binary formation is greatly delayed, as we confirm here both numerically and analytically. The relative duration of core contraction and global expansion is effected by stellar evolution, which causes the most massive stars to die out before they form binaries. In clusters of higher N, the epoch of dynamical relaxation lasts for progressively longer periods. By extrapolating our results to much larger populations we can understand, at least qualitatively, why some globular clusters reach the point of true core collapse. i TO MY MOTHER ii Contents List of Figures v List of Tables vii Acknowledgments viii 1 Introduction and Outline 1 1.1 Clusters of Stars . 1 1.2 Present Understanding . 2 1.2.1 The Formation of Open Clusters . 2 1.2.2 Stellar Dynamical Evolution . 4 1.2.3 Open Cluster Examples . 5 1.3 Outline of Thesis . 7 2 Methodology 9 2.1 Characterizing the Current State of a Cluster . 9 2.1.1 Stellar Mass Probability Function . 9 2.1.2 Maximum Likelihood Analysis . 13 2.1.3 Mass Segregation: The Gini Coefficient . 20 2.1.4 Procedure and Synthetic Data Tests . 23 2.2 Initial Cluster Parameters . 28 2.2.1 Density and Velocity Distribution . 28 2.2.2 Stellar Masses: Single and Binary . 36 2.3 N-Body Simulations . 41 2.3.1 Characterizing the Evolved Cluster . 41 2.3.2 Distribution of Binary Component Masses . 43 2.3.3 Optimization Procedure . 51 3 The Pleiades 54 3.1 Observational Data . 54 3.2 The Pleiades Today . 56 3.2.1 Empirical Mass Distributions . 56 Contents iii 3.2.2 Binarity . 62 3.2.3 Number and Mass Profiles . 63 3.2.4 Mass Segregation . 66 3.2.5 Potential Systematic Uncertainties . 69 3.3 Simulating the Seven Sisters . 73 3.3.1 The Initial State . 73 3.3.2 Past Evolution . 81 3.3.3 Future Evolution . 87 3.3.4 Conclusions from Simulations . 94 4 Alpha Persei 97 4.1 Constructing the Catalog . 97 4.1.1 Membership . 97 4.1.2 Photometry . 98 4.2 Alpha Persei Today: Computational Method . 100 4.2.1 Finding the Mass Function . 100 4.2.2 Cluster Shape . 101 4.3 Alpha Persei Today: Results . 105 4.3.1 Empirical Mass Distribution . 105 4.3.2 Binarity . 107 4.3.3 Surface Density . 110 4.4 Evolutionary Simulations . 114 4.4.1 Numerical Procedure . 114 4.4.2 Initial State . 115 4.4.3 Past Evolution . 118 4.4.4 Future Evolution . 123 4.5 Summary and Discussion of Alpha Persei . 127 4.5.1 Alpha Persei and the Pleiades . 127 4.5.2 Sources of Uncertainty . 129 4.A Alpha Persei Membership Catalog . 130 5 Dynamical Evolution of Clusters 148 5.1 Cluster Energetics . 148 5.1.1 Single-Mass Models . 148 5.1.2 Models with a Realistic Mass Function . 152 5.1.3 The Example of the Pleiades . 155 5.2 The Role of Binaries . 161 5.2.1 First Appearance . 161 5.2.2 Energy Input . 164 5.2.3 Very Massive Stars . 167 5.3 The Role of Stellar Evolution . 169 5.4 Discussion of Real Clusters . 172 Contents iv 5.4.1 Open vs. Globular Clusters . 172 5.4.2 Cluster Death . 174 5.4.3 Summary of Cluster Evolution . 175 Bibliography 176 v List of Figures 2.1 Fraction of systems observed with primary mass mp which are binary. 12 2.2 Sample synthetic data results for the single star mass function φ(m) . 25 2.3 Weighted sum of the biases as a function of the regularization parameter λ. 27 2.4 Comparison of our fitted correlation coefficient c with γ. 29 2.5 Systematic errors in parameters of the lognormal fit to φ(m). 30 3.1 Near-infrared color-magnitude diagram for the Pleiades. 55 3.2 Observational error in the K-band measurements of Pleiades members. 57 3.3 Best-fit single star probability density for the Pleiades. 58 3.4 Comparison of the primary and single star probability density functions.
Load more

Recommended publications
  • Winter Constellations
    Winter Constellations *Orion *Canis Major *Monoceros *Canis Minor *Gemini *Auriga *Taurus *Eradinus *Lepus *Monoceros *Cancer *Lynx *Ursa Major *Ursa Minor *Draco *Camelopardalis *Cassiopeia *Cepheus *Andromeda *Perseus *Lacerta *Pegasus *Triangulum *Aries *Pisces *Cetus *Leo (rising) *Hydra (rising) *Canes Venatici (rising) Orion--Myth: Orion, the great ​ ​ hunter. In one myth, Orion boasted he would kill all the wild animals on the earth. But, the earth goddess Gaia, who was the protector of all animals, produced a gigantic scorpion, whose body was so heavily encased that Orion was unable to pierce through the armour, and was himself stung to death. His companion Artemis was greatly saddened and arranged for Orion to be immortalised among the stars. Scorpius, the scorpion, was placed on the opposite side of the sky so that Orion would never be hurt by it again. To this day, Orion is never seen in the sky at the same time as Scorpius. DSO’s ● ***M42 “Orion Nebula” (Neb) with Trapezium A stellar ​ ​ ​ nursery where new stars are being born, perhaps a thousand stars. These are immense clouds of interstellar gas and dust collapse inward to form stars, mainly of ionized hydrogen which gives off the red glow so dominant, and also ionized greenish oxygen gas. The youngest stars may be less than 300,000 years old, even as young as 10,000 years old (compared to the Sun, 4.6 billion years old). 1300 ly. ​ ​ 1 ● *M43--(Neb) “De Marin’s Nebula” The star-forming ​ “comma-shaped” region connected to the Orion Nebula. ● *M78--(Neb) Hard to see. A star-forming region connected to the ​ Orion Nebula.
    [Show full text]
  • 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.
    [Show full text]
  • 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.
    [Show full text]
  • 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.
    [Show full text]
  • 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.
    [Show full text]
  • 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).
    [Show full text]
  • Optical Astronomy Observatories
    National Optical Astronomy Observatories National Optical Astronomy Observatories Internal Quarterly Report January - March 1989 4 May 1989 TABLE OF CONTENTS I. Introduction 1 n. Personnel 2 Appendices Appendix A: Telescope Usage Statistics Appendix B: Observational Programs I. INTRODUCTION In June 1988, the Division of Astronomical Sciences of the National Science Foundation (NSF) decided that one quarterly report would be timed to coincide with the Annual Presentation to the NSF. Information that would have been included in the second quarter report was, instead, subsumed into material prepared by NOAO for the Annual Centers Presentation to the NSF, held May 18-19, 1989 in Washington, D.C. The NOAO Management Committee decided NOAO would continue to keep quarterly records of statistics. This document contains statistics from the Personnel Office, telescope usage statistics, and observational programs. n. PERSONNEL A. Visiting Scientists. The following visitors arrived at NOAO facilities for periods of one month or more during the January 1 - March 31, 1989 quarter. date NOAO facility arrived name institution visited 1/03/89 Sumner Davis UC Berkeley, California NSO/T 1/03/89 William Holzapfel UC Berkeley, California NSO/T 1/03/89 Nicolas Roddier Steward Obs. 8-m Office 1/15/89 Pierre Connes Centre Nat de la Recherche 8-m Office Scientifique, France 1/15/89 Dick White Lazy FW Ranch, Colorado NSO/T 1/20/89 Tetsuo Aoki Nat. Astromonical Obs., Japan KPNO 2/01/89 Domenico Bonaccini Osservatorio Astrofisico di NSO/SP Arcetri, Italy 2/01/89 Keliang Huang Nanjing U., China KPNO 2/01/89 Sergio Restaino New Jersey Inst, of Technology NSO/SP 2/14/89 Nidia Morrell U.
    [Show full text]
  • 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.
    [Show full text]
  • Annual Report / Rapport Annuel / Jahresbericht 1996
    Annual Report / Rapport annuel / Jahresbericht 1996 ✦ ✦ ✦ E U R O P E A N S O U T H E R N O B S E R V A T O R Y ES O✦ 99 COVER COUVERTURE UMSCHLAG Beta Pictoris, as observed in scattered light Beta Pictoris, observée en lumière diffusée Beta Pictoris, im Streulicht bei 1,25 µm (J- at 1.25 microns (J band) with the ESO à 1,25 microns (bande J) avec le système Band) beobachtet mit dem adaptiven opti- ADONIS adaptive optics system at the 3.6-m d’optique adaptative de l’ESO, ADONIS, au schen System ADONIS am ESO-3,6-m-Tele- telescope and the Observatoire de Grenoble télescope de 3,60 m et le coronographe de skop und dem Koronographen des Obser- coronograph. l’observatoire de Grenoble. vatoriums von Grenoble. The combination of high angular resolution La combinaison de haute résolution angu- Die Kombination von hoher Winkelauflö- (0.12 arcsec) and high dynamical range laire (0,12 arcsec) et de gamme dynamique sung (0,12 Bogensekunden) und hohem dy- (105) allows to image the disk to only 24 AU élevée (105) permet de reproduire le disque namischen Bereich (105) erlaubt es, die from the star. Inside 50 AU, the main plane jusqu’à seulement 24 UA de l’étoile. A Scheibe bis zu einem Abstand von nur 24 AE of the disk is inclined with respect to the l’intérieur de 50 UA, le plan principal du vom Stern abzubilden. Innerhalb von 50 AE outer part. Observers: J.-L. Beuzit, A.-M.
    [Show full text]
  • Atlas Menor Was Objects to Slowly Change Over Time
    C h a r t Atlas Charts s O b by j Objects e c t Constellation s Objects by Number 64 Objects by Type 71 Objects by Name 76 Messier Objects 78 Caldwell Objects 81 Orion & Stars by Name 84 Lepus, circa , Brightest Stars 86 1720 , Closest Stars 87 Mythology 88 Bimonthly Sky Charts 92 Meteor Showers 105 Sun, Moon and Planets 106 Observing Considerations 113 Expanded Glossary 115 Th e 88 Constellations, plus 126 Chart Reference BACK PAGE Introduction he night sky was charted by western civilization a few thou - N 1,370 deep sky objects and 360 double stars (two stars—one sands years ago to bring order to the random splatter of stars, often orbits the other) plotted with observing information for T and in the hopes, as a piece of the puzzle, to help “understand” every object. the forces of nature. The stars and their constellations were imbued with N Inclusion of many “famous” celestial objects, even though the beliefs of those times, which have become mythology. they are beyond the reach of a 6 to 8-inch diameter telescope. The oldest known celestial atlas is in the book, Almagest , by N Expanded glossary to define and/or explain terms and Claudius Ptolemy, a Greco-Egyptian with Roman citizenship who lived concepts. in Alexandria from 90 to 160 AD. The Almagest is the earliest surviving astronomical treatise—a 600-page tome. The star charts are in tabular N Black stars on a white background, a preferred format for star form, by constellation, and the locations of the stars are described by charts.
    [Show full text]
  • Arxiv:2006.10868V2 [Astro-Ph.SR] 9 Apr 2021 Spain and Institut D’Estudis Espacials De Catalunya (IEEC), C/Gran Capit`A2-4, E-08034 2 Serenelli, Weiss, Aerts Et Al
    Noname manuscript No. (will be inserted by the editor) Weighing stars from birth to death: mass determination methods across the HRD Aldo Serenelli · Achim Weiss · Conny Aerts · George C. Angelou · David Baroch · Nate Bastian · Paul G. Beck · Maria Bergemann · Joachim M. Bestenlehner · Ian Czekala · Nancy Elias-Rosa · Ana Escorza · Vincent Van Eylen · Diane K. Feuillet · Davide Gandolfi · Mark Gieles · L´eoGirardi · Yveline Lebreton · Nicolas Lodieu · Marie Martig · Marcelo M. Miller Bertolami · Joey S.G. Mombarg · Juan Carlos Morales · Andr´esMoya · Benard Nsamba · KreˇsimirPavlovski · May G. Pedersen · Ignasi Ribas · Fabian R.N. Schneider · Victor Silva Aguirre · Keivan G. Stassun · Eline Tolstoy · Pier-Emmanuel Tremblay · Konstanze Zwintz Received: date / Accepted: date A. Serenelli Institute of Space Sciences (ICE, CSIC), Carrer de Can Magrans S/N, Bellaterra, E- 08193, Spain and Institut d'Estudis Espacials de Catalunya (IEEC), Carrer Gran Capita 2, Barcelona, E-08034, Spain E-mail: [email protected] A. Weiss Max Planck Institute for Astrophysics, Karl Schwarzschild Str. 1, Garching bei M¨unchen, D-85741, Germany C. Aerts Institute of Astronomy, Department of Physics & Astronomy, KU Leuven, Celestijnenlaan 200 D, 3001 Leuven, Belgium and Department of Astrophysics, IMAPP, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen, the Netherlands G.C. Angelou Max Planck Institute for Astrophysics, Karl Schwarzschild Str. 1, Garching bei M¨unchen, D-85741, Germany D. Baroch J. C. Morales I. Ribas Institute of· Space Sciences· (ICE, CSIC), Carrer de Can Magrans S/N, Bellaterra, E-08193, arXiv:2006.10868v2 [astro-ph.SR] 9 Apr 2021 Spain and Institut d'Estudis Espacials de Catalunya (IEEC), C/Gran Capit`a2-4, E-08034 2 Serenelli, Weiss, Aerts et al.
    [Show full text]
  • 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.
    [Show full text]