Radial Velocities of K–M Dwarfs and Local Stellar Kinematics?
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Characterisation of Young Nearby Stars – the Ursa Major Group
FRIEDRICH-SCHILLER-UNIVERSITAT¨ JENA Physikalisch-Astronomische Fakult¨at Characterisation of young nearby stars – The Ursa Major group Dissertation zur Erlangung des akademischen Grades doctor rerum naturalium (Dr. rer. nat.) vorgelegt dem Rat der Physikalischen-Astronomischen Fakult¨at der Friedrich-Schiller-Universit¨at Jena von Dipl.-Phys. Matthias Ammler geboren am 10.01.1977 in Neuburg a. d. Donau Gutachter 1. Prof. Dr. Ralph Neuh¨auser 2. Dr. habil. Matthias H¨unsch 3. Prof. Dr. Artie P. Hatzes Tag der letzten Rigorosumspr¨ufung: 26. Juni 2006 Tag der ¨offentlichen Verteidigung: 11. Juli 2006 Meinen Eltern Contents List of Figures vii List of Tables ix Abstract xi Zusammenfassung xiii Remarks and Acknowledgements xv 1 Introduction 1 1.1 WhatistheUrsaMajorgroup? . 1 1.1.1 Co-movingstarsin the BigDipper constellation . .... 1 1.1.2 Stellarmotionandmovinggroups . 1 1.1.3 Formation and evolution of open clusters and associations ... 6 1.1.4 The nature of the UMa group – cluster or association, or some- thingelse? ............................ 8 1.2 WhyistheUMagroupinteresting?. 8 1.2.1 Asnapshotinstellarevolution . 8 1.2.2 Alaboratoryinfrontofthedoor . 9 1.2.3 Thecensusofthesolarneighbourhood . 10 1.3 ConstrainingtheUMagroup–previousapproaches . ..... 11 1.3.1 Spatialclustering . 11 1.3.2 Kinematic criteria – derived from a “canonical” memberlist . 12 1.3.3 Kinematic parameters – derived from kinematic clustering ... 15 1.3.4 Stellarparametersandabundances . 17 1.3.5 TheageoftheUMagroup–photometriccriteria . 19 1.3.6 Spectroscopicindicatorsforageandactivity . .... 19 1.3.7 Combining kinematic, spectroscopic, and photometric criteria . 21 1.4 Anewhomogeneousspectroscopicstudy . 21 1.4.1 Definingthesample ....................... 22 1.4.2 Howtoobtainprecisestellarparameters? . .. 23 2 Observations,reductionandcalibration 25 2.1 Requireddata ............................... 25 2.2 Instruments ............................... -
Young Nearby Stars by Adam Conrad Schneider (Under The
Young Nearby Stars by Adam Conrad Schneider (Under the Direction of Professor Inseok Song) Abstract Nearby young stars are without equal as stellar and planetary evolution laboratories. The aim of this work is to use age diagnostic considerations to execute a complete survey for new nearby young stars and to efficiently reevaluate and constrain their ages. Because of their proximity and age, young, nearby stars are the most desired targets for any astrophysical study focusing on the early stages of star and planet formation. Identifying nearby, young, low-mass stars is challenging because of their inherent faint- ness and age diagnostic degeneracies. A new method for identifying these objects has been developed, and a pilot study of its effectiveness is demonstrated by the identification of two definite new members of the TW Hydrae Association. Nearby, young, solar-type stars are initially identified in this work by their fractional X-ray luminosity. The results of a large-scale search for nearby, young, solar-type stars is presented. Follow-up spectroscopic observations are taken in order to measure various age diagnostics in order to accurately assess stellar ages. Age, one of the most fundamental properties of a star, is also one of the most difficult to determine. While a variety of proce- dures have been developed and utilized to approximate ages for solar-type stars, with varying degrees of success, a comprehensive age-dating technique has yet to be constructed. Often- times, different methods exhibit contradictory or conflicting findings. Such inconsistencies demonstrate the value of a uniform method of determining stellar ages. -
Pdf/44/4/905/5386708/44-4-905.Pdf
MI-TH-214 INT-PUB-21-004 Axions: From Magnetars and Neutron Star Mergers to Beam Dumps and BECs Jean-François Fortin∗ Département de Physique, de Génie Physique et d’Optique, Université Laval, Québec, QC G1V 0A6, Canada Huai-Ke Guoy and Kuver Sinhaz Department of Physics and Astronomy, University of Oklahoma, Norman, OK 73019, USA Steven P. Harrisx Institute for Nuclear Theory, University of Washington, Seattle, WA 98195, USA Doojin Kim{ Mitchell Institute for Fundamental Physics and Astronomy, Department of Physics and Astronomy, Texas A&M University, College Station, TX 77843, USA Chen Sun∗∗ School of Physics and Astronomy, Tel-Aviv University, Tel-Aviv 69978, Israel (Dated: February 26, 2021) We review topics in searches for axion-like-particles (ALPs), covering material that is complemen- tary to other recent reviews. The first half of our review covers ALPs in the extreme environments of neutron star cores, the magnetospheres of highly magnetized neutron stars (magnetars), and in neu- tron star mergers. The focus is on possible signals of ALPs in the photon spectrum of neutron stars and gravitational wave/electromagnetic signals from neutron star mergers. We then review recent developments in laboratory-produced ALP searches, focusing mainly on accelerator-based facilities including beam-dump type experiments and collider experiments. We provide a general-purpose discussion of the ALP search pipeline from production to detection, in steps, and our discussion is straightforwardly applicable to most beam-dump type and reactor experiments. We end with a selective look at the rapidly developing field of ultralight dark matter, specifically the formation of Bose-Einstein Condensates (BECs). -
The Twenty−Eight Lunar Mansions of China
浜松医科大学紀要 一般教育 第5号(1991) THE TWENTY-EIGHT LUNAR MANSIONS OF CHINA (中国の二十八宿) David B. Kelley (英 語〉 Abstract: This’Paper attempts to place the development of the Chinese system ・fTw・nty-Eight Luna・ Man・i・n・(;+八宿)i・・血・lti-cult・・al f・am・w・・k, withi・ which, contributions from cultures outside of China may be recognized. lt・ system- atically compares the Chinese system with similar systems from Babylonia, Arabia,・ and lndia. The results of such a comparison not only suggest an early date for its development, but also a significant level of input from, most likely, a Middle Eastern source. Significantly, the data suggest an awareness, on the part of the ancient Chinese, of completely arbitrary groupings of stars (the twelve constellations of the Middle Eastern Zodiac), as well as their equally arbitrary syMbolic associ- ations. The paper also attempts to elucidate the graphic and organizational relation- ship between the Chinese system of lunar mansions and (1.) Phe twelve Earthly Branches(地支)and(2.)the ten Heavenly S.tems(天干). key words二China, Lunar calender, Lunar mansions, Zodiac. O. INTRODUCTION The time it takes the Moon to circle the Earth is 29 days, 12 hours, and 44 minutes. However, the time it takes the moon to return to the same (fixed一) star position amounts to some 28 days. ln China, it is the latter period that was and is of greater significance. The Erh-Shih-Pα一Hsui(一Kung), the Twenty-Eight-lnns(Mansions),二十八 宿(宮),is the usual term in(Mandarin)Chinese, and includes 28 names for each day of such a month. ln East Asia, what is not -
The Chara Array Angular Diameter of Hr 8799 Favors Planetary Masses for Its Imaged Companions
The Astrophysical Journal, 761:57 (15pp), 2012 December 10 doi:10.1088/0004-637X/761/1/57 C 2012. The American Astronomical Society. All rights reserved. Printed in the U.S.A. THE CHARA ARRAY ANGULAR DIAMETER OF HR 8799 FAVORS PLANETARY MASSES FOR ITS IMAGED COMPANIONS Ellyn K. Baines1, Russel J. White2, Daniel Huber3, Jeremy Jones2, Tabetha Boyajian2, Harold A. McAlister2, Theo A. ten Brummelaar2, Nils H. Turner2, Judit Sturmann2, Laszlo Sturmann2, P. J. Goldfinger2, Christopher D. Farrington2, Adric R. Riedel2, Michael Ireland4, Kaspar von Braun5, and Stephen T. Ridgway6 1 Remote Sensing Division, Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, DC 20375, USA; [email protected] 2 Center for High Angular Resolution Astronomy, Georgia State University, P.O. Box 3969, Atlanta, GA 30302-3969, USA 3 NASA Ames Research Center, Moffett Field, CA 94035, USA 4 Department of Physics & Astronomy, Macquarie University, New South Wales, NSW 2109, Australia 5 NASA Exoplanet Science Institute, California Institute of Technology, 770 S. Wilson Ave., MS 100-22, Pasadena, CA 91125-2200, USA 6 Kitt Peak National Observatory, National Optical Astronomy Observatory, P.O. Box 26732, Tucson, AZ 85726-6732, USA Received 2012 July 3; accepted 2012 September 29; published 2012 November 21 ABSTRACT HR 8799 is an hF0 mA5 γ Doradus-, λ Bootis-, Vega-type star best known for hosting four directly imaged candidate planetary companions. Using the CHARA Array interferometer, we measure HR 8799’s limb-darkened angular diameter to be 0.342 ± 0.008 mas (an error of only 2%). By combining our measurement with the star’s parallax and photometry from the literature, we greatly improve upon previous estimates of its fundamental parameters, including stellar radius (1.44 ± 0.06 R), effective temperature (7193 ± 87 K, consistent with F0), luminosity (5.05 ± 0.29 L), and the extent of the habitable zone (HZ; 1.62–3.32 AU). -
Exoplanet Community Report
JPL Publication 09‐3 Exoplanet Community Report Edited by: P. R. Lawson, W. A. Traub and S. C. Unwin National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology Pasadena, California March 2009 The work described in this publication was performed at a number of organizations, including the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (NASA). Publication was provided by the Jet Propulsion Laboratory. Compiling and publication support was provided by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not constitute or imply its endorsement by the United States Government, or the Jet Propulsion Laboratory, California Institute of Technology. © 2009. All rights reserved. The exoplanet community’s top priority is that a line of probeclass missions for exoplanets be established, leading to a flagship mission at the earliest opportunity. iii Contents 1 EXECUTIVE SUMMARY.................................................................................................................. 1 1.1 INTRODUCTION...............................................................................................................................................1 1.2 EXOPLANET FORUM 2008: THE PROCESS OF CONSENSUS BEGINS.....................................................2 -
Incidental Tables
Sp.-V/AQuan/1999/10/27:16:16 Page 667 Chapter 27 Incidental Tables Alan D. Fiala, William F. Van Altena, Stephen T. Ridgway, and Roger W. Sinnott 27.1 The Julian Date ...................... 667 27.2 Standard Epochs ...................... 668 27.3 Reduction for Precession ................. 669 27.4 Solar Coordinates and Related Quantities ....... 670 27.5 Constellations ....................... 672 27.6 The Messier Objects .................... 674 27.7 Astrometry ......................... 677 27.8 Optical and Infrared Interferometry ........... 687 27.9 The World’s Largest Optical Telescopes ........ 689 27.1 THE JULIAN DATE by A.D. Fiala The Julian Day Number (JD) is a sequential count that begins at Noon 1 Jan. 4713 B.C. Julian Calendar. 27.1.1 Julian Dates of Specific Years Noon 1 Jan. 4713 B.C. = JD 0.0 Noon 1 Jan. 1 B.C. = Noon 1 Jan. 0 A.D. = JD 172 1058.0 Noon 1 Jan. 1 A.D. = JD 172 1424.0 A Modified Julian Day (MJD) is defined as JD − 240 0000.5. Table 27.1 gives the Julian Day of some centennial and decennial dates in the Gregorian Calendar. 667 Sp.-V/AQuan/1999/10/27:16:16 Page 668 668 / 27 INCIDENTAL TABLES Table 27.1. Julian date of selected years in the Gregorian calendar [1, 2]. Julian day at noon (UT) on 0 January, Gregorian calendar Jan. 0.5 JD Jan. 0.5 JD Jan. 0.5 JD Jan. 0.5 JD 1500 226 8923 1910 241 8672 1960 243 6934 2010 245 5197 1600 230 5447 1920 242 2324 1970 244 0587 2020 245 8849 1700 234 1972 1930 242 5977 1980 244 4239 2030 246 2502 1800 237 8496 1940 242 9629 1990 244 7892 2040 246 6154 1900 241 5020 1950 243 3282 2000 245 1544 2050 246 9807 Century years evenly divisible by 400 (e.g., 1600, 2000) are leap years. -
A Featureless Transmission Spectrum for the Neptune-Mass Exoplanet GJ 436B
A featureless transmission spectrum for the Neptune-mass exoplanet GJ 436b Heather A. Knutson1, Björn Benneke1,2, Drake Deming3, & Derek Homeier4 1Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA. 2Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. 3Department of Astronomy, University of Maryland, College Park, MD 20742, USA. 4Centre de Recherche Astrophysique de Lyon, 69364 Lyon, France. GJ 436b is a warm (approximately 800 K) extrasolar planet that periodically eclipses its low-mass (0.5 MSun) host star, and is one of the few Neptune-mass planets that is amenable to detailed characterization. Previous observations1,2,3 have indicated that its atmosphere has a methane-to-CO ratio that is 105 times smaller than predicted by models for hydrogen-dominated atmospheres at these temperatures4,5. A recent study proposed that this unusual chemistry could be explained if the planet’s atmosphere is significantly enhanced in elements heavier than H and He6. In this study we present complementary observations of GJ 436b’s atmosphere obtained during transit. Our observations indicate that the planet’s transmission spectrum is effectively featureless, ruling out cloud-free, hydrogen-dominated atmosphere models with a significance of 48σ. The measured spectrum is consistent with either a high cloud or haze layer located at a pressure of approximately 1 mbar or with a relatively hydrogen-poor (3% H/He mass fraction) atmospheric composition7,8,9. We observed four transits of the Neptune-mass planet GJ 436b on UT Oct 26, Nov 29, and Dec 10 2012, and Jan 2 2013 using the red grism (1.2-1.6 µm) on the Hubble Space Telescope (HST) Wide Field Camera 3 instrument. -
Software for Aerospace Educationa Bibliography (Second Edition)
DOCUMENT RESUME ED 312 134 SE 050 904 AUTHOR Vogt, Gregory L.; And Others TITLE Software for Aerospace EducationA Bibliography (Second Edition). INSTITUTION National Aeronautics and Space Administration, Washington, DC. Education Technology Branch. REPORT NO NASA-PED-106 PUB DATE 89 NOTE 91p. PUB TYPE plok/Product Reviews (072) -- Reference Materials - Bibliographies (131) EDRS PRICE MF01/PC04 Plus Postage. DESCRIPTORS *Aerospace Education; Astronomy; *Computer Software; *Computer Software Reviews; *Databases; Elementary School Science; Elementary Secondary Education; Engineering Education; Satellites (Aerospace); Science Fiction; Science Materials; Secondary School Science; *Videodisks IDENTIFIERS National Aeronautics and Space Administration ABSTRACT The software described in this bibliography represents programs made available to the National Aeronautics and Space Administration (NASA) Educational Technology Branch by software producers and vendors. More than 200 computer software programs and 12 laser videodisk programs are reviewed in terms of title, copyright, subject, application, type, grade level, minimum system requir3ments, description, components, features, producer, vendor, and cost. Subject areas covered include: (1) aeronautics; (2) aerospace physics; (3) astronomy; (4) manned space exploration; (5) rocketry; (6) satellites; and (7) science fiction. The last section describes how to use the NASA SpaceLink which is a 24-hour computer information database developed to serve teachers and other educators. Lists of vendors and NASA Teacher Resource Centers are appended. (YP) Reproductions supplied by EDRS are the best that can be made from the original document. Mr sr. O4 i< t E r° 0 2 I. .14l v r3E 51 B `g fh g gc .2- to ch. s 0 ''' t I .1 tacciu'i .cg2; o < 3. f. -
Galactic Center: an Improved Astrometric Reference Frame for Stellar Orbits Around the Supermassive Black Hole Shoko Sakai,1 Jessica R
Draft version January 28, 2019 Typeset using LATEX twocolumn style in AASTeX62 The Galactic Center: An Improved Astrometric Reference Frame for Stellar Orbits around the Supermassive Black Hole Shoko Sakai,1 Jessica R. Lu,2 Andrea Ghez,1 Siyao Jia,2 Tuan Do,1 Gunther Witzel,1 Abhimat K. Gautam,1 Aurelien Hees,3, 1 E. Becklin,1 K. Matthews,4 and M. W. Hosek Jr.5 1UCLA Department of Physics and Astronomy, Los Angeles, CA 90095-1547, USA 2Astronomy Department, University of California, Berkeley, CA 94720, USA 3SYRTE, Observatoire de Paris, Universit´ePSL, CNRS, Sorbonne Universit´e,LNE, 61 avenue de l’Observatoire 75014 Paris 4Astrophysics, California Institute of Technology, MC 249-17, Pasadena, CA 91125, USA 5Institute for Astronomy, University of Hawaii, Honolulu, HI 96822, USA (Received; Revised; Accepted) Submitted to ApJ ABSTRACT Precision measurements of the stars in short-period orbits around the supermassive black hole at the Galactic Center are now being used to constrain general relativistic effects, such as the gravitational redshift and periapse precession. One of the largest systematic uncertainties in the measured orbits has been errors in the astrometric reference frame, which is derived from seven infrared-bright stars associated with SiO masers that have extremely accurate radio positions, measured in the Sgr A*-rest frame. We have improved the astrometric reference frame within 1400 of the Galactic Center by a factor of 2.5 in position and a factor of 5 in proper motion. In the new reference frame, Sgr A* is localized to within a position of 0.645 mas and proper motion of 0.03 mas yr−1. -
Is It a Planet, Asteroid Or a Planetoid? on March 14, 2004 Astronomers at the Palomar Observatory Site Discovered the Most Distant Object in the Solar System
Vol. 35, No. 4 April 2004 Is it a planet, asteroid or a planetoid? On March 14, 2004 astronomers at the Palomar observatory site discovered the most distant object in the solar system. It is 90 AU from the sun, twice as far as anything discovered to date, and three times further than Pluto. It has a highly elliptical orbit that will take it 1000 AU from the sun in the next 5000 years. Its size is estimated to be up to 1800 km, somewhere between the 1250 km of the largest known Kuiper belt object, Quaoar, and the size of Pluto at 2390 km. (Largest asteroid is Ceres at 933 km.) It seems to have a rotational period of 40 days, and appears to be the reddest object in the solar system. Currently known as 2003 VB12, it has been suggested that because of its frigid temperatures it be named Sedna, after the Inuit goddess of the sea. There is much debate on what to call it. It is further than the objects discovered in the Kuiper belt, the zone of large objects discovered around and beyond Pluto, but nearer than the hypothesized Oort cloud zone believed to be the source of comets. It has rekindled the debate over whether Pluto is a planet. If Pluto is a planet then this, and many other large objects, should also be called planets. If this can’t be a planet then maybe Pluto should be declassified. Some have suggested a new category called planetoids. At magnitude 20.5 amateur astronomers won’t have much opportunity to do direct observations of this new object, but we can contribute to the discussion of what the definition of a planet should be. -
Arxiv:2105.12820V1 [Astro-Ph.EP] 26 May 2021 Known with Exquisite Precision
Draft version May 28, 2021 Typeset using LATEX twocolumn style in AASTeX63 The First Dynamical Mass Measurement in the HR 8799 System 1, 1 2 3 G. Mirek Brandt , ∗ Timothy D. Brandt , Trent J. Dupuy , Daniel Michalik , and Gabriel-Dominique Marleau 4, 5, 6 1Department of Physics, University of California, Santa Barbara, Santa Barbara, CA 93106, USA 2Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh, EH9 3HJ, UK 3European Space Agency (ESA), European Space Research and Technology Centre (ESTEC), Keplerlaan 1, 2201 AZ Noordwijk, The Netherlands 4Institut f¨urAstronomie und Astrophysik, Universit¨atT¨ubingen,Auf der Morgenstelle 10, 72076 T¨ubingen,Germany 5Physikalisches Institut, Universit¨atBern, Gesellschaftsstr. 6, 3012 Bern, Switzerland 6Max-Planck-Institut f¨urAstronomie, K¨onigstuhl17, 69117 Heidelberg, Germany (Received April 7, 2021; Revised May 14, 2021; Accepted May 26, 2021) Submitted to ApJ Letters ABSTRACT HR 8799 hosts four directly imaged giant planets, but none has a mass measured from first principles. We present the first dynamical mass measurement in this planetary system, finding that the innermost +1:9 planet HR 8799 e has a mass of 9:6−1:8 MJup. This mass results from combining the well-characterized orbits of all four planets with a new astrometric acceleration detection (5σ) from the Gaia EDR3 version of the Hipparcos-Gaia Catalog of Accelerations. We find with 95% confidence that HR 8799 e +24 is below 13 MJup, the deuterium-fusing mass limit. We derive a hot-start cooling age of 42−16 Myr for HR 8799 e that agrees well with its hypothesized membership in the Columba association but is also consistent with an alternative suggested membership in the β Pictoris moving group.