DOCSLIB.ORG

Applied Statistics

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

ISSN 1932-6157 (print) ISSN 1941-7330 (online) THE ANNALS of APPLIED STATISTICS AN OFFICIAL JOURNAL OF THE INSTITUTE OF MATHEMATICAL STATISTICS Articles A Hermite–Gaussian based exoplanet radial velocity estimation method PARKER H. HOLZER,JESSI CISEWSKI-KEHE,DEBRA FISCHER AND LILY ZHAO 527 Hierarchical integrated spatial process modeling of monotone West Antarctic snow density curves. PHILIP A. WHITE,DURBAN G. KEELER AND SUMMER RUPPER 556 Estimating high-resolution Red Sea surface temperature hotspots, using a low-rank semiparametric spatial model. ARNAB HAZRA AND RAPHAËL HUSER 572 Learning excursion sets of vector-valued Gaussian random fields for autonomous ocean sampling..........TRYGVE OLAV FOSSUM,CÉDRIC TRAVELLETTI,JO EIDSVIK, DAV I D GINSBOURGER AND KANNA RAJAN 597 Aggregated pairwise classification of elastic planar shapes MIN HO CHO,SEBASTIAN KURTEK AND STEVEN N. MACEACHERN 619 A statistical pipeline for identifying physical features that differentiate classes of 3D shapes..............BRUCE WANG,TIMOTHY SUDIJONO,HENRY KIRVESLAHTI, TINGRAN GAO,DOUGLAS M. BOYER, SAYAN MUKHERJEE AND LORIN CRAWFORD 638 Simultaneous inference of periods and period-luminosity relations for Mira variable stars SHIYUAN HE,ZHENFENG LIN,WENLONG YUAN, LUCAS M. MACRI AND JIANHUA Z. HUANG 662 Scalable penalized spatiotemporal land-use regression for ground-level nitrogen dioxide KYLE P. M ESSIER AND MATTHIAS KATZFUSS 688 Probabilistic forecasting of the Arctic sea ice edge with contour modeling HANNAH M. DIRECTOR,ADRIAN E. RAFTERY AND CECILIA M. BITZ 711 Additive stacking for disaggregate electricity demand forecasting CHRISTIAN CAPEZZA,BIAGIO PALUMBO,YANNIG GOUDE, SIMON N. WOOD AND MATTEO FASIOLO 727 Causal mediation analysis for sparse and irregular longitudinal data . SHUXI ZENG, STACY ROSENBAUM,SUSAN C. ALBERTS,ELIZABETH A. ARCHIE AND FAN LI 747 Rapid design of metamaterials via multitarget Bayesian optimization YANG YANG,CHUNLIN JI AND KE DENG 768 A continuous-time semi-Markov model for animal movement in a dynamic environment DEVIN JOHNSON,NOEL PELLAND AND JEREMY STERLING 797 A Bayesian semiparametric Jolly–Seber model with individual heterogeneity: An application to migratory mallards at stopover . GUOHUI WU,SCOTT H. HOLAN, ALEXIS AVRIL AND JONAS WALDENSTRÖM 813 Inference of large modified Poisson-type graphical models: Application to RNA-seq data in childhood atopic asthma studies . .................RONG ZHANG,ZHAO REN, JUAN C. CELEDÓN AND WEI CHEN 831 Two-way sparsity for time-varying networks with applications in genomics THOMAS E. BARTLETT,IOANNIS KOSMIDIS AND RICARDO SILVA 856 continued Vol. 15, No. 2—June 2021 ISSN 1932-6157 (print) ISSN 1941-7330 (online) THE ANNALS of APPLIED STATISTICS AN OFFICIAL JOURNAL OF THE INSTITUTE OF MATHEMATICAL STATISTICS Articles—Continued from front cover A compositional model to assess expression changes from single-cell RNA-seq data XIUYU MA,KEEGAN KORTHAUER, CHRISTINA KENDZIORSKI AND MICHAEL A. NEWTON 880 Large-scale multiple inference of collective dependence with applications to protein function............ROBERT JERNIGAN,KEJUE JIA,ZHAO REN AND WEN ZHOU 902 A Bayesian nonparametric model for inferring subclonal populations from structured DNAsequencingdata................................SHAI HE,AARON SCHEIN, VISHAL SARSANI AND PATRICK FLAHERTY 925 Prediction of the NASH through penalized mixture of logistic regression models MARIE MORVAN,EMILIE DEVIJVER, MADISON GIACOFCI AND VALÉRIE MONBET 952 Efficient Bayesian inference of general Gaussian models on large phylogenetic trees PAUL BASTIDE,LAM SI TUNG HO,GUY BAELE, PHILIPPE LEMEY AND MARC A. SUCHARD 971 A covariance-enhanced approach to multitissue joint eQTL mapping with application to transcriptome-wideassociationstudies......................AARON J. MOLSTAD, WEI SUN AND LI HSU 998 Tensor-variate finite mixture modeling for the analysis of university professor remuneration..........................................SHUCHISMITA SARKAR, VOLODYMYR MELNYKOV AND XUWEN ZHU 1017 Inflection points in community-level homeless rates CHRIS GLYNN,THOMAS H. BYRNE AND DENNIS P. C ULHANE 1037 Length-biased semicompeting risks models for cross-sectional data: An application to currentdurationofpregnancyattemptdata..............ALEXANDER C. MCLAIN, SIYUAN GUO,MARIE THOMA AND JIAJIA ZHANG 1054 A bridging model to reconcile statistics based on data from multiple surveys ANDREEA L. ERCIULESCU,JEAN D. OPSOMER AND F. JAY BREIDT 1068 Vol. 15, No. 2—June 2021 THE ANNALS OF APPLIED STATISTICS Vol. 15, No. 2, pp. 527–1079 June 2021 INSTITUTE OF MATHEMATICAL STATISTICS (Organized September 12, 1935) The purpose of the Institute is to foster the development and dissemination of the theory and applications of statistics and probability. IMS OFFICERS President: Regina Y. Liu, Department of Statistics, Rutgers University, Piscataway, New Jersey 08854-8019, USA President-Elect: Krzysztof Burdzy, Department of Mathematics, University of Washington, Seattle, Washington 98195-4350, USA Past President: Susan Murphy, Department of Statistics, Harvard University, Cambridge, Massachusetts 02138-2901, USA Executive Secretary: Edsel Peña, Department of Statistics, University of South Carolina, Columbia, South Carolina 29208-001, USA Treasurer: Zhengjun Zhang, Department of Statistics, University of Wisconsin, Madison, Wisconsin 53706-1510, USA Program Secretary: Ming Yuan, Department of Statistics, Columbia University, New York, NY 10027-5927, USA IMS PUBLICATIONS The Annals of Statistics. Editors: Richard J. Samworth, Statistical Laboratory, Centre for Mathematical Sciences, University of Cambridge, Cambridge, CB3 0WB, UK. Ming Yuan, Department of Statistics, Columbia University, New York, NY 10027, USA The Annals of Applied Statistics. Editor-In-Chief : Karen Kafadar, Department of Statistics, University of Virginia, Charlottesville, VA 22904-4135, USA The Annals of Probability. Editors: Alice Guionnet, Unité de Mathématiques Pures et Appliquées, ENS de Lyon, Lyon, France. Christophe Garban, Institut Camille Jordan, Université Claude Bernard Lyon 1, 69622 Villeur- banne, France The Annals of Applied Probability. Editors: François Delarue, Laboratoire J. A. Dieudonné, Université de Nice Sophia-Antipolis, France-06108 Nice Cedex 2. Peter Friz, Institut für Mathematik, Technische Universität Berlin, 10623 Berlin, Germany and Weierstrass-Institut für Angewandte Analysis und Stochastik, 10117 Berlin, Germany Statistical Science. Editor: Sonia Petrone, Department of Decision Sciences, Università Bocconi, 20100 Milano MI, Italy The IMS Bulletin. Editor: Vlada Limic, UMR 7501 de l’Université de Strasbourg et du CNRS, 7 rue René Descartes, 67084 Strasbourg Cedex, France The Annals of Applied Statistics [ISSN 1932-6157 (print); ISSN 1941-7330 (online)], Volume 15, Number 2, June 2021. Published quarterly by the Institute of Mathematical Statistics, 9760 Smith Road, Waite Hill, Ohio 44094, USA. Periodicals postage pending at Cleveland, Ohio, and at additional mailing offices. POSTMASTER: Send address changes to The Annals of Applied Statistics, Institute of Mathematical Statistics, Dues and Subscriptions Office, PO Box 729, Middletown, Maryland 21769, USA. Copyright © 2021 by the Institute of Mathematical Statistics Printed in the United States of America The Annals of Applied Statistics 2021, Vol. 15, No. 2, 527–555 https://doi.org/10.1214/20-AOAS1406 © Institute of Mathematical Statistics, 2021 A HERMITE–GAUSSIAN BASED EXOPLANET RADIAL VELOCITY ESTIMATION METHOD BY PARKER H. HOLZER1,JESSI CISEWSKI-KEHE2,DEBRA FISCHER3,* AND LILY ZHAO3,† 1Department of Statistics and Data Science, Yale University, [email protected] 2Department of Statistics, University of Wisconsin–Madison, [email protected] 3Department of Astronomy, Yale University, *debra.fi[email protected]; †[email protected] As the first successful technique used to detect exoplanets orbiting dis- tant stars, the radial velocity method aims to detect a periodic Doppler shift in a stellar spectrum due to the star’s motion along the line sight. We intro- duce a new, mathematically rigorous approach to detect such a signal that accounts for the smooth functional relationship of neighboring wavelengths in the spectrum, minimizes the role of wavelength interpolation, accounts for heteroskedastic noise and easily allows for accurate calculation of the esti- mated radial velocity standard error. Using Hermite–Gaussian functions, we show that the problem of detecting a Doppler shift in the spectrum can be re- duced to linear regression in many settings. A simulation study demonstrates that the proposed method is able to accurately estimate an individual spec- − trum’s radial velocity with precision below 0.3ms 1, corresponding to a Doppler shift much smaller than the size of a spectral pixel. Furthermore, the new method outperforms the traditional cross-correlation function approach for estimating the radial velocity by reducing the root mean squared error − up to 15 cm s 1. The proposed method is also demonstrated on a new set of observations from the EXtreme PREcision Spectrometer (EXPRES) for the host star 51 Pegasi, and successfully recovers estimates of the planetary companion’s parameters that agree well with previous studies. The method is implemented in the R package rvmethod, and supplemental Python code is also available. REFERENCES ANGLADA-ESCUDÉ,G.andBUTLER, R. P. (2012). The harps-terra project. I. Description of the algorithms, performance, and new measurements on a few remarkable stars observed by harps. Astrophys. J., Suppl. Ser. 200
Recommended publications
  • Lurking in the Shadows: Wide-Separation Gas Giants As Tracers of Planet Formation

    Lurking in the Shadows: Wide-Separation Gas Giants As Tracers of Planet Formation

    Lurking in the Shadows: Wide-Separation Gas Giants as Tracers of Planet Formation Thesis by Marta Levesque Bryan In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy CALIFORNIA INSTITUTE OF TECHNOLOGY Pasadena, California 2018 Defended May 1, 2018 ii © 2018 Marta Levesque Bryan ORCID: [0000-0002-6076-5967] All rights reserved iii ACKNOWLEDGEMENTS First and foremost I would like to thank Heather Knutson, who I had the great privilege of working with as my thesis advisor. Her encouragement, guidance, and perspective helped me navigate many a challenging problem, and my conversations with her were a consistent source of positivity and learning throughout my time at Caltech. I leave graduate school a better scientist and person for having her as a role model. Heather fostered a wonderfully positive and supportive environment for her students, giving us the space to explore and grow - I could not have asked for a better advisor or research experience. I would also like to thank Konstantin Batygin for enthusiastic and illuminating discussions that always left me more excited to explore the result at hand. Thank you as well to Dimitri Mawet for providing both expertise and contagious optimism for some of my latest direct imaging endeavors. Thank you to the rest of my thesis committee, namely Geoff Blake, Evan Kirby, and Chuck Steidel for their support, helpful conversations, and insightful questions. I am grateful to have had the opportunity to collaborate with Brendan Bowler. His talk at Caltech my second year of graduate school introduced me to an unexpected population of massive wide-separation planetary-mass companions, and lead to a long-running collaboration from which several of my thesis projects were born.
  • IAU Division C Working Group on Star Names 2019 Annual Report

    IAU Division C Working Group on Star Names 2019 Annual Report

    IAU Division C Working Group on Star Names 2019 Annual Report Eric Mamajek (chair, USA) WG Members: Juan Antonio Belmote Avilés (Spain), Sze-leung Cheung (Thailand), Beatriz García (Argentina), Steven Gullberg (USA), Duane Hamacher (Australia), Susanne M. Hoffmann (Germany), Alejandro López (Argentina), Javier Mejuto (Honduras), Thierry Montmerle (France), Jay Pasachoff (USA), Ian Ridpath (UK), Clive Ruggles (UK), B.S. Shylaja (India), Robert van Gent (Netherlands), Hitoshi Yamaoka (Japan) WG Associates: Danielle Adams (USA), Yunli Shi (China), Doris Vickers (Austria) WGSN Website: https://www.iau.org/science/scientific_bodies/working_groups/280/ ​ WGSN Email: [email protected] ​ The Working Group on Star Names (WGSN) consists of an international group of astronomers with expertise in stellar astronomy, astronomical history, and cultural astronomy who research and catalog proper names for stars for use by the international astronomical community, and also to aid the recognition and preservation of intangible astronomical heritage. The Terms of Reference and membership for WG Star Names (WGSN) are provided at the IAU website: https://www.iau.org/science/scientific_bodies/working_groups/280/. ​ ​ ​ WGSN was re-proposed to Division C and was approved in April 2019 as a functional WG whose scope extends beyond the normal 3-year cycle of IAU working groups. The WGSN was specifically called out on p. 22 of IAU Strategic Plan 2020-2030: “The IAU serves as the ​ internationally recognised authority for assigning designations to celestial bodies and their surface features. To do so, the IAU has a number of Working Groups on various topics, most notably on the nomenclature of small bodies in the Solar System and planetary systems under Division F and on Star Names under Division C.” WGSN continues its long term activity of researching cultural astronomy literature for star names, and researching etymologies with the goal of adding this information to the WGSN’s online materials.
  • Know the Star, Know the Planet. I. Adaptive Optics of Exoplanet Host Stars

    Know the Star, Know the Planet. I. Adaptive Optics of Exoplanet Host Stars

    The Astronomical Journal, 142:175 (7pp), 2011 November doi:10.1088/0004-6256/142/5/175 C 2011. The American Astronomical Society. All rights reserved. Printed in the U.S.A. KNOW THE STAR, KNOW THE PLANET. I. ADAPTIVE OPTICS OF EXOPLANET HOST STARS Lewis C. Roberts, Jr.1, Nils H. Turner2, Theo A. ten Brummelaar2, Brian D. Mason3, and William I. Hartkopf3 1 Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA; [email protected] 2 Center for High Angular Resolution Astronomy, Georgia State University, Mt. Wilson, CA 91023, USA; [email protected], [email protected] 3 U.S. Naval Observatory, 3450 Massachusetts Avenue, NW, Washington, DC 20392-5420, USA; [email protected], [email protected] Received 2011 June 27; accepted 2011 September 19; published 2011 October 17 ABSTRACT The results of an adaptive optics survey of exoplanet host stars for stellar companions are presented. We used the Advanced Electro-Optical System telescope and its adaptive optics system to collect deep images of the stars in the I band. Sixty-two exoplanet host stars were observed and fifteen multiple star systems were resolved. Of these eight are known multiples, while seven are new candidate binaries. For all binaries, we measured the relative astrometry of the pair and the differential magnitude in the I band. We improved the orbits of HD 19994 and τ Boo. These observations will provide improved statistics on the duplicity of exoplanet host stars and provide an increased understanding of the dynamics of known binary star exoplanet hosts.
  • Statistical Properties of Exoplanets

    Statistical Properties of Exoplanets

    A&A 398, 363–376 (2003) Astronomy DOI: 10.1051/0004-6361:20021637 & c ESO 2003 Astrophysics Statistical properties of exoplanets II. Metallicity, orbital parameters, and space velocities N. C. Santos1, G. Israelian2, M. Mayor1,R.Rebolo2,3,andS.Udry1 1 Observatoire de Gen`eve, 51 ch. des Maillettes, 1290 Sauverny, Switzerland 2 Instituto de Astrof´ısica de Canarias, 38200 La Laguna, Tenerife, Spain 3 Consejo Superior de Investigaciones Cient´ıficas, Spain Received 19 September 2002 / Accepted 7 November 2002 Abstract. In this article we present a detailed spectroscopic analysis of more than 50 extra-solar planet host stars. Stellar atmospheric parameters and metallicities are derived using high resolution and high S/N spectra. The spectroscopy results, added to the previous studies, imply that we have access to a large and uniform sample of metallicities for about 80 planet hosts stars. We make use of this sample to confirm the metal-rich nature of stars with planets, and to show that the planetary frequency is rising as a function of the [Fe/H]. Furthermore, the source of this high metallicity is shown to have most probably a “primordial” source, confirming previous results. The comparison of the orbital properties (period and eccentricity) and minimum masses of the planets with the stellar properties also reveal some emerging but still not significant trends. These are discussed and some explanations are proposed. Finally, we show that the planet host stars included in the CORALIE survey have similar kinematical properties as the whole CORALIE volume-limited planet search sample. Planet hosts simply seem to occupy the metal-rich envelope of this latter population.
  • PDF, on the Incidence of Wise Infrared Excess Among Solar

    PDF, on the Incidence of Wise Infrared Excess Among Solar

    The Astrophysical Journal, 837:15 (11pp), 2017 March 1 doi:10.3847/1538-4357/837/1/15 © 2017. The American Astronomical Society. All rights reserved. On the Incidence of Wise Infrared Excess Among Solar Analog, Twin, and Sibling Stars A. D. Da Costa1, B. L. Canto Martins1, I. C. Leão2, J. E. Lima Jr1, D. Freire da Silva1, D. B. de Freitas3, and J. R. De Medeiros1 1 Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, Campus Universitário, Natal, RN, 59072-970, Brazil; dgerson@fisica.ufrn.br 2 European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching, Germany 3 Departamento de Física, Universidade Federal do Ceará, Caixa Postal 6030, Campus do Pici, 60455-900, Fortaleza, Ceará, Brazil Received 2016 April 25; revised 2016 November 3; accepted 2016 November 6; published 2017 February 27 Abstract This study presents a search for infrared (IR) excess in the 3.4, 4.6, 12, and 22 μm bands in a sample of 216 targets, composed of solar sibling, twin, and analog stars observed by the Wide-field Infrared Survey Explorer (WISE) mission. In general, an IR excess suggests the existence of warm dust around a star. We detected 12 μm and/or 22 μm excesses at the 3σ level of confidence in five solar analog stars, corresponding to a frequency of 4.1% of the entire sample of solar analogs analyzed, and in one out of 29 solar sibling candidates, confirming previous studies. The estimation of the dust properties shows that the sources with IR excesses possess circumstellar material with temperatures that, within the uncertainties, are similar to that of the material found in the asteroid belt in our solar system.
  • Serpens – the Serpent

    Serpens – the Serpent

    A JPL Image of surface of Mars, and JPL Ingenuity Helicioptor illustration, in flight Monthly Meeting May 10th at 7:00 PM at HRPO, and via Jitsi (Monthly meetings are on 2nd Mondays at Highland Road Park Observatory, will also broadcast via. (meet.jit.si/BRASMeet). PRESENTATION: Dr. Alan Hale, professional astronomer and co-discoverer of Comet Hale-Bopp, among other endeavors. What's In This Issue? President’s Message Member Meeting Minutes Business Meeting Minutes Outreach Report Light Pollution Committee Report Globe at Night SubReddit and Discord Messages from the HRPO REMOTE DISCUSSION Solar Viewing International Astronomy Day American Radio Relay League Field Day Observing Notes: Serpens - The Serpent & Mythology Like this newsletter? See PAST ISSUES online back to 2009 Visit us on Facebook – Baton Rouge Astronomical Society BRAS YouTube Channel Baton Rouge Astronomical Society Newsletter, Night Visions Page 2 of 20 May 2021 President’s Message Ahhh, welcome to May, the last pleasant month in Louisiana before the start of the hurricane season and the brutal summer months that follow. April flew by pretty quickly, and with the world slowly thawing from the long winter, why shouldn’t it? To celebrate, we decided we’re going to try to start holding our monthly meetings at Highland Road Park Observatory again, only with the added twist of incorporating an on-line component for those who for whatever reason don’t feel like making it out. To that end, we’ll have both our usual live broadcast on the BRAS YouTube channel and the Brasmeet page on Jitsi—which is where our out of town guests and, at least this month, our guest speaker can join us.
  • Determining the True Mass of Radial-Velocity Exoplanets with Gaia 9 Planet Candidates in the Brown-Dwarf/Stellar Regime and 27 Confirmed Planets

    Determining the True Mass of Radial-Velocity Exoplanets with Gaia 9 Planet Candidates in the Brown-Dwarf/Stellar Regime and 27 Confirmed Planets

    Astronomy & Astrophysics manuscript no. exoplanet_mass_gaia c ESO 2020 September 30, 2020 Determining the true mass of radial-velocity exoplanets with Gaia 9 planet candidates in the brown-dwarf/stellar regime and 27 confirmed planets F. Kiefer1; 2, G. Hébrard1; 3, A. Lecavelier des Etangs1, E. Martioli1; 4, S. Dalal1, and A. Vidal-Madjar1 1 Institut d’Astrophysique de Paris, Sorbonne Université, CNRS, UMR 7095, 98 bis bd Arago, 75014 Paris, France 2 LESIA, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Université de Paris, 5 place Jules Janssen, 92195 Meudon, France? 3 Observatoire de Haute-Provence, CNRS, Universiteé d’Aix-Marseille, 04870 Saint-Michel-l’Observatoire, France 4 Laboratório Nacional de Astrofísica, Rua Estados Unidos 154, 37504-364, Itajubá - MG, Brazil Submitted on 2020/08/20 ; Accepted for publication on 2020/09/24 ABSTRACT Mass is one of the most important parameters for determining the true nature of an astronomical object. Yet, many published exoplan- ets lack a measurement of their true mass, in particular those detected thanks to radial velocity (RV) variations of their host star. For those, only the minimum mass, or m sin i, is known, owing to the insensitivity of RVs to the inclination of the detected orbit compared to the plane-of-the-sky. The mass that is given in database is generally that of an assumed edge-on system (∼90◦), but many other inclinations are possible, even extreme values closer to 0◦ (face-on). In such case, the mass of the published object could be strongly underestimated by up to two orders of magnitude.
  • Evidence for Enhanced Chromospheric Ca II H and K Emission in Stars with Close-In Extrasolar Planets

    Evidence for Enhanced Chromospheric Ca II H and K Emission in Stars with Close-In Extrasolar Planets

    A&A 540, A82 (2012) Astronomy DOI: 10.1051/0004-6361/201118247 & c ESO 2012 Astrophysics Evidence for enhanced chromospheric Ca II H and K emission in stars with close-in extrasolar planets T. Krejcovᡠ1 and J. Budaj2 1 Department of Theoretical Physics and Astrophysics, Masaryk University, Kotlárskᡠ2, 61137 Brno, Czech Republic e-mail: [email protected] 2 Astronomical Institute, Slovak Academy of Sciences, 05960 Tatranská Lomnica, Slovak Republic e-mail: [email protected] Received 11 October 2011 / Accepted 13 February 2012 ABSTRACT Context. The planet-star interaction is manifested in many ways. It has been found that a close-in exoplanet causes small but mea- surable variability in the cores of a few lines in the spectra of several stars, which corresponds to the orbital period of the exoplanet. Stars with and without exoplanets may have different properties. Aims. The main goal of our study is to search for the influence that exoplanets might have on atmospheres of their host stars. Unlike the previous studies, we do not study changes in the spectrum of a host star or differences between stars with and without exoplanets. We aim to study a large number of stars with exoplanets and the current level of their chromospheric activity and to look for a possible correlation with the exoplanetary properties. Methods. To analyse the chromospheric activity of stars, we exploited our own and publicly available archival spectra, measured the equivalent widths of the cores of Ca II H and K lines, and used them to trace their activity. Subsequently, we searched for their dependence on the orbital parameters and the mass of the exoplanet.
  • C, S, Zn and Cu Abundances in Planet-Harbouring Stars�,

    C, S, Zn and Cu Abundances in Planet-Harbouring Stars,

    A&A 426, 619–630 (2004) Astronomy DOI: 10.1051/0004-6361:20041136 & c ESO 2004 Astrophysics C, S, Zn and Cu abundances in planet-harbouring stars, A. Ecuvillon1, G. Israelian1,N.C.Santos2,3, M. Mayor3, V. Villar4, and G. Bihain1 1 Instituto de Astrofísica de Canarias, 38200 La Laguna, Tenerife, Spain e-mail: [email protected] 2 Centro de Astronomia e Astrofisica de Universidade de Lisboa, Observatorio Astronomico de Lisboa, Tapada de Ajuda, 1349-018 Lisboa, Portugal 3 Observatoire de Genève, 51 ch. des Maillettes, 1290 Sauverny, Switzerland 4 Departamento de Astrofísica, Fac. de Físicas, Universidad Complutense de Madrid, Ciudad Universitaria, 28040 Madrid, Spain Received 21 April 2004 / Accepted 17 June 2004 Abstract. We present a detailed and uniform study of C, S, Zn and Cu abundances in a large set of planet host stars, as well as in a homogeneous comparison sample of solar-type dwarfs with no known planetary-mass companions. Carbon abundances were derived by EW measurement of two C optical lines, while spectral syntheses were performed for S, Zn and Cu. We investigated possible differences in the behaviours of the volatiles C, S and Zn and in the refractory Cu in targets with and without known planets in order to check possible anomalies due to the presence of planets. We found that the abundance distributions in stars with exoplanets are the high [Fe/H] extensions of the trends traced by the comparison sample. All volatile elements we studied show [X/Fe] trends decreasing with [Fe/H] in the metallicity range −0.8 < [Fe/H] < 0.5, with significantly negative slopes of −0.39 ± 0.04 and −0.35 ± 0.04 for C and S, respectively.
  • IAU WGSN 2019 Annual Report

    IAU WGSN 2019 Annual Report

    IAU Division C Working Group on Star Names 2019 Annual Report Eric Mamajek (chair, USA) WG Members: Juan Antonio Belmote Avilés (Spain), Sze-leung Cheung (Thailand), Beatriz García (Argentina), Steven Gullberg (USA), Duane Hamacher (Australia), Susanne M. Hoffmann (Germany), Alejandro López (Argentina), Javier Mejuto (Honduras), Thierry Montmerle (France), Jay Pasachoff (USA), Ian Ridpath (UK), Clive Ruggles (UK), B.S. Shylaja (India), Robert van Gent (Netherlands), Hitoshi Yamaoka (Japan) WG Associates: Danielle Adams (USA), Yunli Shi (China), Doris Vickers (Austria) WGSN Website: https://www.iau.org/science/scientific_bodies/working_groups/280/ WGSN Email: [email protected] The Working Group on Star Names (WGSN) consists of an international group of astronomers with expertise in stellar astronomy, astronomical history, and cultural astronomy who research and catalog proper names for stars for use by the international astronomical community, and also to aid the recognition and preservation of intangible astronomical heritage. The Terms of Reference and membership for WG Star Names (WGSN) are provided at the IAU website: https://www.iau.org/science/scientific_bodies/working_groups/280/. WGSN was re-proposed to Division C and was approved in April 2019 as a functional WG whose scope extends beyond the normal 3-year cycle of IAU working groups. The WGSN was specifically called out on p. 22 of IAU Strategic Plan 2020-2030: “The IAU serves as the internationally recognised authority for assigning designations to celestial bodies and their surface features. To do so, the IAU has a number of Working Groups on various topics, most notably on the nomenclature of small bodies in the Solar System and planetary systems under Division F and on Star Names under Division C.” WGSN continues its long term activity of researching cultural astronomy literature for star names, and researching etymologies with the goal of adding this information to the WGSN’s online materials.
  • • Methods. on 2012 Feb 29, the Extrasolar Planets Encyclopaedia (Exoplanet.Eu) Tabulated 699 Planet Candidates in 558 Plane

    • Methods. on 2012 Feb 29, the Extrasolar Planets Encyclopaedia (Exoplanet.Eu) Tabulated 699 Planet Candidates in 558 Plane

    • Context. Young exoplanetary systems with ages τ ≤ 600 Ma (i.e. Hyades-like or younger) provide constraints on the time scale and mechanism of planet formation and on the planet evolution (orbital migration, late heavy bombardment...). Apart from the very young “planet” candidates found by direct imaging (around e.g. HR 8799, 2M1207-39 or AB Pic), some young planet candidates have been found with the radial velocity method, such as HD 70573b (Setiawan et al. 2007) in the Hercules-Lyra subgroup of the Local Association or the controversial TW Hya b and BD+20 1790b (Setiawan et al. 2008; Hernán-Obispo et al. 2010). On the other hand, there may be old exoplanetary systems, whose stars belong to the thick disc or even the Galactic halo (CD-36 1052b, Setiawan et al. 2010). • Aims. We search for bright Hipparcos stars with radial-velocity planets that are member candidates in young moving groups (Montes et al. 2001), such as the Hyades, IC 2391, Ursa Majoris and Castor superclusters and the Local Association (τ = 100-600 Ma), and very young moving groups like β Pictoris or TW Hydrae (τ < 100 Ma). Generally, these stars are discarded from accurate radial-velocity searches based on activity indicators, but there might be young stars that passed the rejection filter (e.g. HD 81040, τ ~ 700 Ma; Sozzetti et al. 2006). We also look for old exoplanet host stars in the Galactic thick disc and the thin-thick transition. • Methods. On 2012 Feb 29, the Extrasolar Planets Encyclopaedia (exoplanet.eu) tabulated 699 planet candidates in 558 planetary systems detected by radial velocity (93 multiple planet systems).
  • Astronomie Pentru Şcolari

    Astronomie Pentru Şcolari

    NICU GOGA CARTE DE ASTRONOMIE Editura REVERS CRAIOVA, 2010 Referent ştiinţific: Prof. univ.dr. Radu Constantinescu Editura Revers ISBN: 978-606-92381-6-5 2 În contextul actual al restructurării învăţământului obligatoriu, precum şi al unei manifeste lipse de interes din partea tinerei generaţii pentru studiul disciplinelor din aria curiculară Ştiinţe, se impune o intensificare a activităţilor de promovare a diferitelor discipline ştiinţifice. Dintre aceste discipline Astronomia ocupă un rol prioritar, având în vedere că ea intermediază tinerilor posibilitatea de a învăţa despre lumea în care trăiesc, de a afla tainele şi legile care guvernează Universul. În plus, anul 2009 a căpătat o co-notaţie specială prin declararea lui de către UNESCO drept „Anul Internaţional al Astronomiei”. În acest context, domnul profesor Nicu Goga ne propune acum o a doua carte cu tematică de Astronomie. După apariţia lucrării Geneza, evoluţia şi sfârşitul Universului, un volum care s+a bucurat de un real succes, apariţia lucrării „Carte de Astronomie” reprezintă un adevărat eveniment editorial, cu atât mai mult cu cât ea constitue în acelaşi timp un material monografic şi un material cu caracter didactic. Cartea este structurată în 13 capitole, trecând în revistă problematica generală a Astronomiei cu puţine elemente de Cosmologie. Cartea îşi propune şi reuşeşte pe deplin să ofere răspunsuri la câteva întrebări fundamentale şi tulburătoare legate de existenţa fiinţei umane şi a dimensiunii cosmice a acestei existenţe, incită la dialog şi la dorinţa de cunoaştere. Consider că, în ansamblul său, cartea poate contribui la îmbunătăţirea educaţiei ştiinţifice a tinerilor elevi şi este deosebit de utilă pentru toţi „actorii” implicaţi în procesul de predare-învăţare: elevi, părinţi, profesori.