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Starshade Exoplanet Data Challenge
Starshade exoplanet data challenge a,b, a,c a Renyu Hu , * Sergi R. Hildebrandt , Mario Damiano, a a a Stuart Shaklan , Stefan Martin , and Doug Lisman a Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, United States b California Institute of Technology, Division of Geological and Planetary Sciences, Pasadena, California, United States c California Institute of Technology, Division of Physics, Mathematics and Astronomy, Pasadena, California, United States Abstract. Starshade in formation flight with a space telescope is a rapidly maturing technology that would enable imaging and spectral characterization of small planets orbiting nearby stars in the not-too-distant future. While performance models of starshade-assisted exoplanet imaging have been developed and used to design future missions, their results have not been verified from the analyses of synthetic images. Following a rich history of using community data challenges to evaluate image-processing capabilities in astronomy and exoplanet fields, the Starshade Technology Development to TRL5 (S5), a focused technology development activity managed by the NASA Exoplanet Exploration Program, is organizing and implementing a starshade exo- planet data challenge. The purpose of the data challenge is to validate the flow down of require- ments from science to key instrument performance parameters and to quantify the required accuracy of noisy background calibration with synthetic images. This data challenge distin- guishes itself from past efforts in the exoplanet field in that (1) it focuses on the detection and spectral characterization of small planets in the habitable zones of nearby stars, and (2) it devel- ops synthetic images that simultaneously include multiple background noise terms—some observations specific to starshade—including residual starlight, solar glint, exozodiacal light, detector noise, as well as variability resulting from starshade’s motion and telescope jitter. -
“A Brief History of Beiji (Northern Culmen)”
“A Brief History of Beiji (Northern Culmen)” (Prepared for the 4th International Conference on the Inspiration of Astronomical Phenomena INSAP IV, Oxford University, August 3-9, 2003.) David W. Pankenier Lehigh University Abstract: In ancient Chinese astral lore, the imperial nomenclature associated with the circumpolar stars in the Palace of Purple Tenuity points to the crucial importance of the north-pole in astrological, calendrical, and spiritual contexts. But preoccupation with this numinous region has a history far longer than the Chinese empire, founded in 221 BCE. This paper briefly surveys what is known about the pre-imperial history of the region of the ‘Northern Culmen,’ with particular reference to spiritual and metaphysical conceptions relating to the Northern Dipper, and to the void at the pivot of the heavens which lacked a pole star throughout much of the formative period of classical Chinese civilization. The discussion concludes with a hypothesis about the astral origins of the ancient form of the character used to denote the High God di. Chinese preoccupation with astronomical orientation has a very long history. Archaeological evidence from the 5th millennium BCE Neolithic cultures of North China shows that burials and dwellings were already being oriented with particular attention to the diurnal and seasonal variations in the Sun’s position.1 By the early Bronze Age in the early 2nd millennium BCE and the inception of early state formation, such concepts had progressed to the point where ritually and politically important structures were uniformly quadrilateral in shape, and cardinally oriented, with the longitudinal axis aligned with some precision in a north-south direction.2 Palatial structures and royal tombs from the earliest dynastic states in the 2nd millennium BCE, that is, Xia, Shang, and Zhou, consistently display such orientation. -
Detecting Reflected Light from Close-In Extrasolar Giant Planets with the Kepler Photometer
Accepted for publication by the Astrophysical Journal 05/2003 Detecting Reflected Light from Close-In Extrasolar Giant Planets with the Kepler Photometer Jon M. Jenkins SETI Institute/NASA Ames Research Center, MS 244-30, Moffett Field, CA 94035 [email protected] and Laurance R. Doyle SETI Institute, 2035 Landings Drive, Mountain View, CA 94043 [email protected] ABSTRACT NASA’s Kepler Mission promises to detect transiting Earth-sized planets in the habitable zones of solar-like stars. In addition, it will be poised to detect the reflected light component from close-in extrasolar giant planets (CEGPs) similar to 51 Peg b. Here we use the DIARAD/SOHO time series along with models for the reflected light signatures of CEGPs to evaluate Kepler’s ability to detect arXiv:astro-ph/0305473v1 24 May 2003 such planets. We examine the detectability as a function of stellar brightness, stellar rotation period, planetary orbital inclination angle, and planetary orbital period, and then estimate the total number of CEGPs that Kepler will detect over its four year mission. The analysis shows that intrinsic stellar variability of solar-like stars is a major obstacle to detecting the reflected light from CEGPs. Monte Carlo trials are used to estimate the detection threshold required to limit the total number of expected false alarms to no more than one for a survey of 100,000 stellar light curves. Kepler will likely detect 100-760 51 Peg b-like planets by reflected light with orbital periods up to 7 days. Subject headings: planetary systems — techniques: photometry — methods: data analysis –2– 1. -
News from the Society for Astronomical Sciences
News from the Society for Astronomical Sciences Vol . 9 No. 2 (April, 2011 ) Triennial Election of SAS the powerful Wilson-Devinney (WD) follows the general style of regular program used by most professionals in papers. These should be sent to the Committee the field. PHOEBE is a cross-platform Program Committee (prior to the April The SAS is a non-profit public benefit (Linux/Unix, Windows, OS X) graphical 16 deadline), to be included in the pub- corporation incorporated in California, program that greatly simplifies the use lished Proceedings. of WD. which is managed by a Board of Direc- tors. The Directors are elected for 3- The workshop will consist of a mix of year terms by the membership. The lecture-style background information SAS 2011 Symposium: current Directors’ terms of office will and hands-on analysis of real data. end on June 1, 2011. Accordingly, the Registration Information 2011 Symposium will include a brief Dirk Terrell is an astrophysicist at the 2011 marks the 30 th Anniversary of the business meeting to elect 7 Directors Southwest Research Institute's De- Society for Astronomical Sciences! to hold office for the next three years. partment of Space Studies in Boulder, This year’s Symposium is shaping up Colorado. His research work focuses The following candidates will be pre- to offer a diverse array of talks, work- mainly on theoretical and observa- shops, and networking opportunities, sented to the Membership for approval tional aspects of close binary stars. He as Directors, to serve from June 2, so you do not want to miss out. -
THE VALLEY SKYWATCHER Volume 47 Number 3 Summer 2010
THE VALLEY SKYWATCHER Volume 47 Number 3 Summer 2010 The Valley Skywatcher is the official publication of the Chagrin Valley Astronomical Society, founded 1963. Our mailing address is PO Box 11, Chagrin Falls, OH 44022 More information can be found on our web site: www.chagrinvalleyastronomy.org Editor: Dan Rothstein Table of Contents: A Few Summer Double Stars George Gliba Constellation Quiz Dan Rothstein Discovery History and Recent Light Curves for 1700 Zvezdara Ron Baker Astronomical Alignments in Ireland Dan Rothstein A Few Summer Double Stars - by G.W. Gliba There are many fine double stars available in the Summer sky that can be split in a small refractor or medium size reflector this time of the year. One of my favorite is Xi Bootids, because it was originally thought to be the radiant to a solo minor meteorite shower, which is now known to be a complex of several radiants, now recognized by the IAU as the Bootid-Corona Borealis Complex. It can be split with a good 2.4-inch refractor. The components consists of a 4.8 magnitude primary star that is a G8V with a 7th magnitude companion of K5V spec. type, which appears yellow and orange respectively to an observer. This star system is 22 light years distant. The G8V component is also a variable star of low amplitude know as a BY Draconis type star, which varies from 4.52 to 4.67 over 10.137 days. However, this variability can't be noticed visually. Much easier and more colorful is the nice pair Epsilon Bootis nearby, also known as Izar. -
Flares on Active M-Type Stars Observed with XMM-Newton and Chandra
Flares on active M-type stars observed with XMM-Newton and Chandra Urmila Mitra Kraev Mullard Space Science Laboratory Department of Space and Climate Physics University College London A thesis submitted to the University of London for the degree of Doctor of Philosophy I, Urmila Mitra Kraev, confirm that the work presented in this thesis is my own. Where information has been derived from other sources, I confirm that this has been indicated in the thesis. Abstract M-type red dwarfs are among the most active stars. Their light curves display random variability of rapid increase and gradual decrease in emission. It is believed that these large energy events, or flares, are the manifestation of the permanently reforming magnetic field of the stellar atmosphere. Stellar coronal flares are observed in the radio, optical, ultraviolet and X-rays. With the new generation of X-ray telescopes, XMM-Newton and Chandra , it has become possible to study these flares in much greater detail than ever before. This thesis focuses on three core issues about flares: (i) how their X-ray emission is correlated with the ultraviolet, (ii) using an oscillation to determine the loop length and the magnetic field strength of a particular flare, and (iii) investigating the change of density sensitive lines during flares using high-resolution X-ray spectra. (i) It is known that flare emission in different wavebands often correlate in time. However, here is the first time where data is presented which shows a correlation between emission from two different wavebands (soft X-rays and ultraviolet) over various sized flares and from five stars, which supports that the flare process is governed by common physical parameters scaling over a large range. -
Arxiv:1408.0401V1 [Astro-Ph.EP] 2 Aug 2014 Page Intentionally Left Blank
arXiv:1408.0401v1 [astro-ph.EP] 2 Aug 2014 Page intentionally left blank. Development and Application of Tools to Characterize Transiting Astrophysical Systems A dissertation presented by Bence B´eky to The Department of Astronomy in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the subject of Astronomy and Astrophysics Harvard University Cambridge, Massachusetts 2014 April Copyright c 2014 Bence B´eky All rights reserved. Dissertation Advisor: Author: Dr. Matthew Holman Bence B´eky Development and Application of Tools to Characterize Transiting Astrophysical Systems Abstract Since the discovery of the first exoplanets (planets outside our Solar System) more than 20 years ago, there has been an increasing need for photometric and spectroscopic models to characterize these systems. While imaging has been used extensively for Solar System bodies and extended objects like galaxies, the small angular extent of typical planetary systems makes it difficult or impossible to resolve them. Spatially integrated observations like measuring the total brightness or spectrum, however, can be conducted at a resonable cost. This thesis focuses on photometric models in the context of transiting systems, which exhibit a number of phenomena that can be exploited for characterization. First, we showcase the popular methods of transiting exoplanet discovery and characterization by ground based observations on the hot Jupiter HAT-P-27b. We demonstrate how transits allow us to constrain planetary mass, radius, and orbital inclination, which would not be possible based only on, for example, radial velocity measurements. Next, we perform reflection spectroscopy on HAT-P-1b, another hot Jupiter, using the binary companion of the host star as a reference to remove systematic errors from iii the signal. -
Gaia Data Release 2 Special Issue
A&A 623, A110 (2019) Astronomy https://doi.org/10.1051/0004-6361/201833304 & © ESO 2019 Astrophysics Gaia Data Release 2 Special issue Gaia Data Release 2 Variable stars in the colour-absolute magnitude diagram?,?? Gaia Collaboration, L. Eyer1, L. Rimoldini2, M. Audard1, R. I. Anderson3,1, K. Nienartowicz2, F. Glass1, O. Marchal4, M. Grenon1, N. Mowlavi1, B. Holl1, G. Clementini5, C. Aerts6,7, T. Mazeh8, D. W. Evans9, L. Szabados10, A. G. A. Brown11, A. Vallenari12, T. Prusti13, J. H. J. de Bruijne13, C. Babusiaux4,14, C. A. L. Bailer-Jones15, M. Biermann16, F. Jansen17, C. Jordi18, S. A. Klioner19, U. Lammers20, L. Lindegren21, X. Luri18, F. Mignard22, C. Panem23, D. Pourbaix24,25, S. Randich26, P. Sartoretti4, H. I. Siddiqui27, C. Soubiran28, F. van Leeuwen9, N. A. Walton9, F. Arenou4, U. Bastian16, M. Cropper29, R. Drimmel30, D. Katz4, M. G. Lattanzi30, J. Bakker20, C. Cacciari5, J. Castañeda18, L. Chaoul23, N. Cheek31, F. De Angeli9, C. Fabricius18, R. Guerra20, E. Masana18, R. Messineo32, P. Panuzzo4, J. Portell18, M. Riello9, G. M. Seabroke29, P. Tanga22, F. Thévenin22, G. Gracia-Abril33,16, G. Comoretto27, M. Garcia-Reinaldos20, D. Teyssier27, M. Altmann16,34, R. Andrae15, I. Bellas-Velidis35, K. Benson29, J. Berthier36, R. Blomme37, P. Burgess9, G. Busso9, B. Carry22,36, A. Cellino30, M. Clotet18, O. Creevey22, M. Davidson38, J. De Ridder6, L. Delchambre39, A. Dell’Oro26, C. Ducourant28, J. Fernández-Hernández40, M. Fouesneau15, Y. Frémat37, L. Galluccio22, M. García-Torres41, J. González-Núñez31,42, J. J. González-Vidal18, E. Gosset39,25, L. P. Guy2,43, J.-L. Halbwachs44, N. C. Hambly38, D. -
The Coronal X-Ray – Age Relation and Its Implications for the Evaporation of Exoplanets
Mon. Not. R. Astron. Soc. 000, 1–20 (2011) Printed 24 October 2018 (MN LATEX style file v2.2) The coronal X-ray – age relation and its implications for the evaporation of exoplanets Alan P. Jackson1,2⋆, Timothy A. Davis1,3⋆ and Peter J. Wheatley4 1Sub-Department of Astrophysics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford, UK, OX1 3RH 2Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge, UK, CB3 0HA 3European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748, Garching bei Muenchen, Germany 4Department of Physics, University of Warwick, Gibbet Hill Road, Coventry, UK, CV4 7AL Submitted 2011 ABSTRACT We study the relationship between coronal X-ray emission and stellar age for late-type stars, and the variation of this relationship with spectral type. We select 717 stars from 13 open clusters and find that the ratio of X-ray to bolometric luminosity during the saturated phase of coronal emission decreases from 10−3.1 for late K-dwarfs to 10−4.3 for early F-type stars (across the range 0.29 6 (B − V )0 < 1.41). Our determined saturation timescales vary between 107.8 and 108.3 years, though with no clear trend across the whole FGK range. We apply our X-ray emission – age relations to the investigation of the evaporation history of 121 known transiting exoplanets using a simple energy-limited model of evaporation and taking into consideration Roche lobe effects and different heating/evaporation efficiencies. We confirm that a linear cut-off of the planet distribution in the M 2/R3 versus a−2 plane is an expected result of population modification by evaporation and show that the known transiting exoplanets display such a cut-off. -
00E the Construction of the Universe Symphony
The basic construction of the Universe Symphony. There are 30 asterisms (Suites) in the Universe Symphony. I divided the asterisms into 15 groups. The asterisms in the same group, lay close to each other. Asterisms!! in Constellation!Stars!Objects nearby 01 The W!!!Cassiopeia!!Segin !!!!!!!Ruchbah !!!!!!!Marj !!!!!!!Schedar !!!!!!!Caph !!!!!!!!!Sailboat Cluster !!!!!!!!!Gamma Cassiopeia Nebula !!!!!!!!!NGC 129 !!!!!!!!!M 103 !!!!!!!!!NGC 637 !!!!!!!!!NGC 654 !!!!!!!!!NGC 659 !!!!!!!!!PacMan Nebula !!!!!!!!!Owl Cluster !!!!!!!!!NGC 663 Asterisms!! in Constellation!Stars!!Objects nearby 02 Northern Fly!!Aries!!!41 Arietis !!!!!!!39 Arietis!!! !!!!!!!35 Arietis !!!!!!!!!!NGC 1056 02 Whale’s Head!!Cetus!! ! Menkar !!!!!!!Lambda Ceti! !!!!!!!Mu Ceti !!!!!!!Xi2 Ceti !!!!!!!Kaffalijidhma !!!!!!!!!!IC 302 !!!!!!!!!!NGC 990 !!!!!!!!!!NGC 1024 !!!!!!!!!!NGC 1026 !!!!!!!!!!NGC 1070 !!!!!!!!!!NGC 1085 !!!!!!!!!!NGC 1107 !!!!!!!!!!NGC 1137 !!!!!!!!!!NGC 1143 !!!!!!!!!!NGC 1144 !!!!!!!!!!NGC 1153 Asterisms!! in Constellation Stars!!Objects nearby 03 Hyades!!!Taurus! Aldebaran !!!!!! Theta 2 Tauri !!!!!! Gamma Tauri !!!!!! Delta 1 Tauri !!!!!! Epsilon Tauri !!!!!!!!!Struve’s Lost Nebula !!!!!!!!!Hind’s Variable Nebula !!!!!!!!!IC 374 03 Kids!!!Auriga! Almaaz !!!!!! Hoedus II !!!!!! Hoedus I !!!!!!!!!The Kite Cluster !!!!!!!!!IC 397 03 Pleiades!! ! Taurus! Pleione (Seven Sisters)!! ! ! Atlas !!!!!! Alcyone !!!!!! Merope !!!!!! Electra !!!!!! Celaeno !!!!!! Taygeta !!!!!! Asterope !!!!!! Maia !!!!!!!!!Maia Nebula !!!!!!!!!Merope Nebula !!!!!!!!!Merope -
New Highprecision Orbital and Physical Parameters of the Doublelined Lowmass Spectroscopic Binary by Draconis
Mon. Not. R. Astron. Soc. 419, 1285–1293 (2012) doi:10.1111/j.1365-2966.2011.19785.x New high-precision orbital and physical parameters of the double-lined low-mass spectroscopic binary BY Draconis , , K. G. Hełminiak,1,2 M. Konacki,1 3 M. W. Muterspaugh,4 5 S. E. Browne,6 A. W. Howard7 and S. R. Kulkarni8 1Department of Astrophysics, Nicolaus Copernicus Astronomical Center, ul. Rabianska´ 8, 87-100 Torun,´ Poland 2Departamento de Astronom´ıa y Astrof´ısica, Pontificia Universidad Catolica,´ Casilla 306, Santiago, Chile 3Astronomical Observatory, A. Mickiewicz University, ul. Słoneczna 36, 60-286 Poznan,´ Poland 4Department of Mathematics and Physics, College of Arts and Sciences, Tennessee State University, Boswell Science Hall, Nashville, TN 37209, USA 5Center of Excellence in Information Systems, Tennessee State University, 3500 John A. Merritt Blvd., Box No 9501, Nashville, TN 37203-3401, USA 6Experimental Astrophysics Group, Space Sciences Laboratory, University of California, 7 Gauss Way, Berkeley, CA 94720, USA 7UC Berkeley Astronomy Department, Campbell Hall MC 3411, Berkeley, CA 94720, USA 8Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, CA 91125, USA Accepted 2011 September 8. Received 2011 September 7; in original form 2010 June 28 ABSTRACT We present the most precise to date orbital and physical parameters of the well-known short period (P = 5.975 d), eccentric (e = 0.3) double-lined spectroscopic binary BY Draconis (BY Dra), a prototype of a class of late-type, active, spotted flare stars. We calculate the full spectroscopic/astrometric orbital solution by combining our precise radial velocities (RVs) and the archival astrometric measurements from the Palomar Testbed Interferometer (PTI). -
Variable Star
Variable star A variable star is a star whose brightness as seen from Earth (its apparent magnitude) fluctuates. This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are classified as either: Intrinsic variables, whose luminosity actually changes; for example, because the star periodically swells and shrinks. Extrinsic variables, whose apparent changes in brightness are due to changes in the amount of their light that can reach Earth; for example, because the star has an orbiting companion that sometimes Trifid Nebula contains Cepheid variable stars eclipses it. Many, possibly most, stars have at least some variation in luminosity: the energy output of our Sun, for example, varies by about 0.1% over an 11-year solar cycle.[1] Contents Discovery Detecting variability Variable star observations Interpretation of observations Nomenclature Classification Intrinsic variable stars Pulsating variable stars Eruptive variable stars Cataclysmic or explosive variable stars Extrinsic variable stars Rotating variable stars Eclipsing binaries Planetary transits See also References External links Discovery An ancient Egyptian calendar of lucky and unlucky days composed some 3,200 years ago may be the oldest preserved historical document of the discovery of a variable star, the eclipsing binary Algol.[2][3][4] Of the modern astronomers, the first variable star was identified in 1638 when Johannes Holwarda noticed that Omicron Ceti (later named Mira) pulsated in a cycle taking 11 months; the star had previously been described as a nova by David Fabricius in 1596. This discovery, combined with supernovae observed in 1572 and 1604, proved that the starry sky was not eternally invariable as Aristotle and other ancient philosophers had taught.