May 2018 BRAS Newsletter
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CENTAURI II Benutzerhandbuch
CENTAURI II Benutzerhandbuch SW-Version ab 3.1.0.73 MAYAH, CENTAURI, FLASHCAST sind eingetragene Warenzeichen. Alle anderen verwendeten Warenzeichen werden hiermit anerkannt. CENTAURI II Benutzerhandbuch ab SW 3.1.0.73 Bestell-Nr. CIIUM001 Stand 11/2005 (c) Copyright by MAYAH Communications GmbH Die Vervielfältigung des vorliegenden Handbuches, sowie der darin besprochenen Dokumentationen aus dem Internet, auch nur auszugsweise, ist nur mit ausdrücklicher schriftlicher Genehmigung der MAYAH Communications GmbH erlaubt. 1 Einführung ........................................................................................................... 1 1.1 Vorwort......................................................................................................... 1 1.2 Einbau / Installation ...................................................................................... 2 1.3 Lieferumfang ................................................................................................ 2 1.4 Umgebungs- / Betriebsbedingung................................................................ 2 1.5 Anschlüsse................................................................................................... 3 2 Verbindungsaufbau ............................................................................................. 4 2.1 ISDN Verbindungen mit dem Centauri II ...................................................... 4 2.1.1 FlashCast Technologie und Audiocodec Kategorien............................. 4 2.1.2 Wie bekomme ich eine synchronisierte Verbindung -
Arxiv:1809.07342V1 [Astro-Ph.SR] 19 Sep 2018
Draft version September 21, 2018 Preprint typeset using LATEX style emulateapj v. 11/10/09 FAR-ULTRAVIOLET ACTIVITY LEVELS OF F, G, K, AND M DWARF EXOPLANET HOST STARS* Kevin France1, Nicole Arulanantham1, Luca Fossati2, Antonino F. Lanza3, R. O. Parke Loyd4, Seth Redfield5, P. Christian Schneider6 Draft version September 21, 2018 ABSTRACT We present a survey of far-ultraviolet (FUV; 1150 { 1450 A)˚ emission line spectra from 71 planet- hosting and 33 non-planet-hosting F, G, K, and M dwarfs with the goals of characterizing their range of FUV activity levels, calibrating the FUV activity level to the 90 { 360 A˚ extreme-ultraviolet (EUV) stellar flux, and investigating the potential for FUV emission lines to probe star-planet interactions (SPIs). We build this emission line sample from a combination of new and archival observations with the Hubble Space Telescope-COS and -STIS instruments, targeting the chromospheric and transition region emission lines of Si III,N V,C II, and Si IV. We find that the exoplanet host stars, on average, display factors of 5 { 10 lower UV activity levels compared with the non-planet hosting sample; this is explained by a combination of observational and astrophysical biases in the selection of stars for radial-velocity planet searches. We demonstrate that UV activity-rotation relation in the full F { M star sample is characterized by a power-law decline (with index α ≈ −1.1), starting at rotation periods & 3.5 days. Using N V or Si IV spectra and a knowledge of the star's bolometric flux, we present a new analytic relationship to estimate the intrinsic stellar EUV irradiance in the 90 { 360 A˚ band with an accuracy of roughly a factor of ≈ 2. -
Durham E-Theses
Durham E-Theses First visibility of the lunar crescent and other problems in historical astronomy. Fatoohi, Louay J. How to cite: Fatoohi, Louay J. (1998) First visibility of the lunar crescent and other problems in historical astronomy., Durham theses, Durham University. Available at Durham E-Theses Online: http://etheses.dur.ac.uk/996/ Use policy The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that: • a full bibliographic reference is made to the original source • a link is made to the metadata record in Durham E-Theses • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders. Please consult the full Durham E-Theses policy for further details. Academic Support Oce, Durham University, University Oce, Old Elvet, Durham DH1 3HP e-mail: [email protected] Tel: +44 0191 334 6107 http://etheses.dur.ac.uk me91 In the name of Allah, the Gracious, the Merciful >° 9 43'' 0' eji e' e e> igo4 U61 J CO J: lic 6..ý v Lo ý , ý.,, "ý J ýs ýºý. ur ý,r11 Lýi is' ý9r ZU LZJE rju No disaster can befall on the earth or in your souls but it is in a book before We bring it into being; that is easy for Allah. In order that you may not grieve for what has escaped you, nor be exultant at what He has given you; and Allah does not love any prideful boaster. -
Explore the Universe Observing Certificate Second Edition
RASC Observing Committee Explore the Universe Observing Certificate Second Edition Explore the Universe Observing Certificate Welcome to the Explore the Universe Observing Certificate Program. This program is designed to provide the observer with a well-rounded introduction to the night sky visible from North America. Using this observing program is an excellent way to gain knowledge and experience in astronomy. Experienced observers find that a planned observing session results in a more satisfying and interesting experience. This program will help introduce you to amateur astronomy and prepare you for other more challenging certificate programs such as the Messier and Finest NGC. The program covers the full range of astronomical objects. Here is a summary: Observing Objective Requirement Available Constellations and Bright Stars 12 24 The Moon 16 32 Solar System 5 10 Deep Sky Objects 12 24 Double Stars 10 20 Total 55 110 In each category a choice of objects is provided so that you can begin the certificate at any time of the year. In order to receive your certificate you need to observe a total of 55 of the 110 objects available. Here is a summary of some of the abbreviations used in this program Instrument V – Visual (unaided eye) B – Binocular T – Telescope V/B - Visual/Binocular B/T - Binocular/Telescope Season Season when the object can be best seen in the evening sky between dusk. and midnight. Objects may also be seen in other seasons. Description Brief description of the target object, its common name and other details. Cons Constellation where object can be found (if applicable) BOG Ref Refers to corresponding references in the RASC’s The Beginner’s Observing Guide highlighting this object. -
Prospects of Detecting the Polarimetric Signature of the Earth-Mass Planet Α Centauri B B with SPHERE/ZIMPOL
A&A 556, A64 (2013) Astronomy DOI: 10.1051/0004-6361/201321881 & c ESO 2013 Astrophysics Prospects of detecting the polarimetric signature of the Earth-mass planet α Centauri B b with SPHERE/ZIMPOL J. Milli1,2, D. Mouillet1,D.Mawet2,H.M.Schmid3, A. Bazzon3, J. H. Girard2,K.Dohlen4, and R. Roelfsema3 1 Institut de Planétologie et d’Astrophysique de Grenoble (IPAG), University Joseph Fourier, CNRS, BP 53, 38041 Grenoble, France e-mail: [email protected] 2 European Southern Observatory, Casilla 19001, Santiago 19, Chile 3 Institute for Astronomy, ETH Zurich, 8093 Zurich, Switzerland 4 Laboratoire d’Astrophysique de Marseille (LAM),13388 Marseille, France Received 12 May 2013 / Accepted 4 June 2013 ABSTRACT Context. Over the past five years, radial-velocity and transit techniques have revealed a new population of Earth-like planets with masses of a few Earth masses. Their very close orbit around their host star requires an exquisite inner working angle to be detected in direct imaging and sets a challenge for direct imagers that work in the visible range, such as SPHERE/ZIMPOL. Aims. Among all known exoplanets with less than 25 Earth masses we first predict the best candidate for direct imaging. Our primary objective is then to provide the best instrument setup and observing strategy for detecting such a peculiar object with ZIMPOL. As a second step, we aim at predicting its detectivity. Methods. Using exoplanet properties constrained by radial velocity measurements, polarimetric models and the diffraction propaga- tion code CAOS, we estimate the detection sensitivity of ZIMPOL for such a planet in different observing modes of the instrument. -
A Proxy for Stellar Extreme Ultraviolet Fluxes
Astronomy & Astrophysics manuscript no. main ©ESO 2020 November 2, 2020 Ca ii H&K stellar activity parameter: a proxy for stellar Extreme Ultraviolet Fluxes A. G. Sreejith1, L. Fossati1, A. Youngblood2, K. France2, and S. Ambily2 1 Space Research Institute, Austrian Academy of Sciences, Schmiedlstrasse 6, 8042 Graz, Austria e-mail: [email protected] 2 Laboratory for Atmospheric and Space Physics, University of Colorado, UCB 600, Boulder, CO, 80309, USA Received date / Accepted date ABSTRACT Atmospheric escape is an important factor shaping the exoplanet population and hence drives our understanding of planet formation. Atmospheric escape from giant planets is driven primarily by the stellar X-ray and extreme-ultraviolet (EUV) radiation. Furthermore, EUV and longer wavelength UV radiation power disequilibrium chemistry in the middle and upper atmosphere. Our understanding of atmospheric escape and chemistry, therefore, depends on our knowledge of the stellar UV fluxes. While the far-ultraviolet fluxes can be observed for some stars, most of the EUV range is unobservable due to the lack of a space telescope with EUV capabilities and, for the more distant stars, to interstellar medium absorption. Thus, it becomes essential to have indirect means for inferring EUV fluxes from features observable at other wavelengths. We present here analytic functions for predicting the EUV emission of F-, G-, K-, and M-type ′ stars from the log RHK activity parameter that is commonly obtained from ground-based optical observations of the ′ Ca ii H&K lines. The scaling relations are based on a collection of about 100 nearby stars with published log RHK and EUV flux values, where the latter are either direct measurements or inferences from high-quality far-ultraviolet (FUV) spectra. -
Naming the Extrasolar Planets
Naming the extrasolar planets W. Lyra Max Planck Institute for Astronomy, K¨onigstuhl 17, 69177, Heidelberg, Germany [email protected] Abstract and OGLE-TR-182 b, which does not help educators convey the message that these planets are quite similar to Jupiter. Extrasolar planets are not named and are referred to only In stark contrast, the sentence“planet Apollo is a gas giant by their assigned scientific designation. The reason given like Jupiter” is heavily - yet invisibly - coated with Coper- by the IAU to not name the planets is that it is consid- nicanism. ered impractical as planets are expected to be common. I One reason given by the IAU for not considering naming advance some reasons as to why this logic is flawed, and sug- the extrasolar planets is that it is a task deemed impractical. gest names for the 403 extrasolar planet candidates known One source is quoted as having said “if planets are found to as of Oct 2009. The names follow a scheme of association occur very frequently in the Universe, a system of individual with the constellation that the host star pertains to, and names for planets might well rapidly be found equally im- therefore are mostly drawn from Roman-Greek mythology. practicable as it is for stars, as planet discoveries progress.” Other mythologies may also be used given that a suitable 1. This leads to a second argument. It is indeed impractical association is established. to name all stars. But some stars are named nonetheless. In fact, all other classes of astronomical bodies are named. -
Abstracts of Papers and Posters Presented at the 97Th Annual Meeting of the AAVSO, Held in Nantucket, Massachusetts, October 16–19, 2008
Abstracts, JAAVSO Volume 37, 2009 193 Abstracts of Papers and Posters Presented at the 97th Annual Meeting of the AAVSO, Held in Nantucket, Massachusetts, October 16–19, 2008 The International Year of Astronomy and Citizen Science Aaron Price AAVSO, 49 Bay State Road, Cambridge, MA 02138 Abstract 2009 has been endorsed as the International Year of Astronomy by both the United Nations and the United States Congress. This talk will briefly outline the IYA cornerstone projects and then will go into more detail regarding the AAVSO’s role as leading a citizen science project regarding the variable star epsilon Aurigae. Variable Star Astronomy Education Outreach Initiative Donna L. Young The Wright Center for Innovative Science, Tufts University, 4 Colby Street, Medford, MA 02155 Abstract The American Association of Variable Star Observers (AAVSO) published a comprehensive variable star curriculum, Hands-On Astrophysics, Variable Stars in Science, Math, and Computer Education in 1997. The curriculum, funded by the National Science Foundation, was developed for a comprehensive audience—amateur astronomers, classroom educators, science fair projects, astronomy clubs, family learning, and anyone interested in learning about variable stars. Some of the activities from the Hands-On Astrophysics curriculum have been incorporated into the educational materials for the Chandra X-Ray Observatory’s Educational and Public Outreach (EPO) Office. On two occasions, in 2000 and 2001, triggered by alerts from amateur astronomers, Chandra observed the outburst of the dwarf nova SS Cygni. The cooperation of amateur variable star astronomers and Chandra X-Ray scientists provided proof that the collaboration of amateur and professional astronomers is a powerful tool to study cosmic phenomena. -
The Radio Continuum View of Centaurus Acentaurus A
TheThe radioradio continuumcontinuum viewview ofof CentaurusCentaurus AA Ron Ekers CSIRO The Many Faces of Centaurus A Sydney, 29 June 2009 Ilana's composite Morganti et al. 1999 9° 10' Burns et al. xx image courtesy Norbert Junkes (MPIfR) WhyWhy CentaurusCentaurus AA isis specialspecial ■ the first extragalactic radio source ■ the brightest source in the Southern Hemisphere ■ the second double lobed source discovered ± after Cygnus A ■ the closest Radio Galaxy ■ the closest AGN ■ the closest SMBH ± VLBI resolution 0.01pc, 100 Rs ■ A spectacular galaxy EvolutionEvolution ofof thethe ModelsModels ■ Radio sources ± Static magnetic field 1960 ± Evolutionary sequence 1970 ± Continuous injection ± Continuous reacceleration ■ Energy source ± Galaxy collisions 1950's ± Nuclear accretions 1960- ± Accretion triggered by collisions 1980- CentaurusCentaurus AA thethe closestclosest AGNAGN ■ Distance 3.4Mpc ■ Next closest comparable AGN M87 17Mpc ! ■ Average distance to a L=1024 W Hz-1 radio galaxies ± 10Mpc ± So we are lucky (or influenced!) ■ Much easier to study at all wavelengths ■ Subtends a large angular size ± Good linear resolution ± Background probes SomeSome RadioRadio GalaxiesGalaxies Name Size Log Log (kpc) Luminosity Energy (ergs sec-1) (ergs) Centaurus A 470 41.7 59.9 Cygnus A 200 45.2 60.6 M87 80 42.0 58.6 M82 1 39.5 55.2 PolarizationPolarization inin CentaurusCentaurus AA Bracewell 1962 ■ April 1962 ■ Parkes 64m just completed ■ Discovered by Bracewell ± Published Cooper and Price ± Visitors Log ± Not a National Facilities yet! ■ Connie -
Arxiv:2007.04823V1 [Astro-Ph.HE] 9 Jul 2020 Inverse Compton-CMB Models , Although Other Evidence Seems to Be Compatible With
Title: Resolving acceleration to very high energies along the Jet of Centaurus A Author: The H.E.S.S. Collaboration Correspondence to: [email protected] The full author list with affiliations can be found at the end of this paper Summary: The nearby radio galaxy Centaurus A belongs to a class of Active Galaxies that are very luminous at radio wavelengths. The majority of these galaxies show collimated relativistic outflows known as jets, that extend over hundreds of thousands of parsecs for the most powerful sources. Accretion of matter onto the central super-massive black hole is be- lieved to fuel these jets and power their emission 1, with the radio emission being related to the synchrotron radiation of relativistic electrons in magnetic fields. The origin of the extended X-ray emission seen in the kiloparsec-scale jets from these sources is still a mat- ter of debate, although Centaurus A’s X-ray emission has been suggested to originate in electron synchrotron processes 2–4. The other possible explanation is inverse Compton scat- tering with CMB soft photons 5–7. Synchrotron radiation needs ultra-relativistic electrons (∼ 50 TeV), and given their short cooling times, requires some continuous re-acceleration mechanism to be active 8. Inverse Compton scattering, on the other hand, does not require very energetic electrons, but requires jets that stay highly relativistic on large scales (≥1 Mpc) and that remain well-aligned with the line of sight. Some recent evidence disfavours 9–12 arXiv:2007.04823v1 [astro-ph.HE] 9 Jul 2020 inverse Compton-CMB models , although other evidence seems to be compatible with them 13, 14. -
Astronomy Astrophysics
A&A 432, 219–224 (2005) Astronomy DOI: 10.1051/0004-6361:20041125 & c ESO 2005 Astrophysics Whole Earth Telescope observations of BPM 37093: A seismological test of crystallization theory in white dwarfs A. Kanaan1, A. Nitta2,D.E.Winget3,S.O.Kepler4, M. H. Montgomery5,3,T.S.Metcalfe6,3, H. Oliveira1, L. Fraga1,A.F.M.daCosta4,J.E.S.Costa4,B.G.Castanheira4, O. Giovannini7,R.E.Nather3, A. Mukadam3, S. D. Kawaler8, M. S. O’Brien8,M.D.Reed8,9,S.J.Kleinman2,J.L.Provencal10,T.K.Watson11,D.Kilkenny12, D. J. Sullivan13, T. Sullivan13, B. Shobbrook14,X.J.Jiang15, B. N. Ashoka16,S.Seetha16, E. Leibowitz17, P. Ibbetson17, H. Mendelson17,E.G.Meištas18,R.Kalytis18, D. Ališauskas19, D. O’Donoghue12, D. Buckley12, P. Martinez12,F.vanWyk12,R.Stobie12, F. Marang12,L.vanZyl12,W.Ogloza20, J. Krzesinski20,S.Zola20,21, P. Moskalik22,M.Breger23,A.Stankov23, R. Silvotti24,A.Piccioni25, G. Vauclair26,N.Dolez26, M. Chevreton27, J. Deetjen28, S. Dreizler28,29,S.Schuh28,29, J. M. Gonzalez Perez30, R. Østensen31, A. Ulla32, M. Manteiga32, O. Suarez32,M.R.Burleigh33, and M. A. Barstow33 Received 20 April 2004 / Accepted 31 October 2004 Abstract. BPM 37093 is the only hydrogen-atmosphere white dwarf currently known which has sufficient mass (∼1.1 M)to theoretically crystallize while still inside the ZZ Ceti instability strip (Teff ∼ 12 000 K). As a consequence, this star represents our first opportunity to test crystallization theory directly. If the core is substantially crystallized, then the inner boundary for each pulsation mode will be located at the top of the solid core rather than at the center of the star, affecting mainly the average period spacing. -
Correlations Between the Stellar, Planetary, and Debris Components of Exoplanet Systems Observed by Herschel⋆
A&A 565, A15 (2014) Astronomy DOI: 10.1051/0004-6361/201323058 & c ESO 2014 Astrophysics Correlations between the stellar, planetary, and debris components of exoplanet systems observed by Herschel J. P. Marshall1,2, A. Moro-Martín3,4, C. Eiroa1, G. Kennedy5,A.Mora6, B. Sibthorpe7, J.-F. Lestrade8, J. Maldonado1,9, J. Sanz-Forcada10,M.C.Wyatt5,B.Matthews11,12,J.Horner2,13,14, B. Montesinos10,G.Bryden15, C. del Burgo16,J.S.Greaves17,R.J.Ivison18,19, G. Meeus1, G. Olofsson20, G. L. Pilbratt21, and G. J. White22,23 (Affiliations can be found after the references) Received 15 November 2013 / Accepted 6 March 2014 ABSTRACT Context. Stars form surrounded by gas- and dust-rich protoplanetary discs. Generally, these discs dissipate over a few (3–10) Myr, leaving a faint tenuous debris disc composed of second-generation dust produced by the attrition of larger bodies formed in the protoplanetary disc. Giant planets detected in radial velocity and transit surveys of main-sequence stars also form within the protoplanetary disc, whilst super-Earths now detectable may form once the gas has dissipated. Our own solar system, with its eight planets and two debris belts, is a prime example of an end state of this process. Aims. The Herschel DEBRIS, DUNES, and GT programmes observed 37 exoplanet host stars within 25 pc at 70, 100, and 160 μm with the sensitiv- ity to detect far-infrared excess emission at flux density levels only an order of magnitude greater than that of the solar system’s Edgeworth-Kuiper belt. Here we present an analysis of that sample, using it to more accurately determine the (possible) level of dust emission from these exoplanet host stars and thereafter determine the links between the various components of these exoplanetary systems through statistical analysis.