Herbig Ae/Be Stars the Missing Link in Star Formation
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The Denver Observer December 2017
The Denver DECEMBER 2017 OBSERVER Messier 76, the Little Dumbbell Nebula, one of the deep-sky objects featured in this month’s “Skies.” Image © Joe Gafford. DECEMBER SKIES by Zachary Singer The Solar System of view in your ’scope will include the Moon’s Sky Calendar 3 Full Moon December will be a decent month for eastern section and the star, with plenty of 10 Last-Quarter Moon planetary events; though some planets are room. 17 New Moon slipping from view, others will take their I recommend you observe early—it 26 First-Quarter Moon place. We also have an occultation of Alde- should be a beautiful view, with the star a baran; as seen from Denver, the Moon will bright spark near the Moon’s edge, and over pass in front of the star at approximately the following minutes (they’ll go fast, just like In the Observer 4:06 PM, on the 30th. At that point, with the recent solar eclipse did), you can see the Moon move in its orbit around us, using the sunset still more than half an hour away, the President’s Message . .2 star won’t be visible to the naked eye, but it star for a benchmark. (Before 4:00 PM, look Society Directory. 2 should be in a telescope if you know where for Aldebaran outside the square, but along to look: Imagine a square drawn just large the diagonal from the Moon’s center to that Schedule of Events . 2 enough to touch the edges of the Moon, and lower-left edge.) About Denver Astronomical Society . -
METEOR CSILLAGÁSZATI ÉVKÖNYV 2019 Meteor Csillagászati Évkönyv 2019
METEOR CSILLAGÁSZATI ÉVKÖNYV 2019 meteor csillagászati évkönyv 2019 Szerkesztette: Benkő József Mizser Attila Magyar Csillagászati Egyesület www.mcse.hu Budapest, 2018 Az évkönyv kalendárium részének összeállításában közreműködött: Tartalom Bagó Balázs Görgei Zoltán Kaposvári Zoltán Kiss Áron Keve Kovács József Bevezető ....................................................................................................... 7 Molnár Péter Sánta Gábor Kalendárium .............................................................................................. 13 Sárneczky Krisztián Szabadi Péter Cikkek Szabó Sándor Szőllősi Attila Zsoldos Endre: 100 éves a Nemzetközi Csillagászati Unió ........................191 Zsoldos Endre Maria Lugaro – Kereszturi Ákos: Elemkeletkezés a csillagokban.............. 203 Szabó Róbert: Az OGLE égboltfelmérés 25 éve ........................................218 A kalendárium csillagtérképei az Ursa Minor szoftverrel készültek. www.ursaminor.hu Beszámolók Mizser Attila: A Magyar Csillagászati Egyesület Szakmailag ellenőrizte: 2017. évi tevékenysége .........................................................................242 Szabados László Kiss László – Szabó Róbert: Az MTA CSFK Csillagászati Intézetének 2017. évi tevékenysége .........................................................................248 Petrovay Kristóf: Az ELTE Csillagászati Tanszékének működése 2017-ben ............................................................................ 262 Szabó M. Gyula: Az ELTE Gothard Asztrofi zikai Obszervatórium -
The Maunder Minimum and the Variable Sun-Earth Connection
The Maunder Minimum and the Variable Sun-Earth Connection (Front illustration: the Sun without spots, July 27, 1954) By Willie Wei-Hock Soon and Steven H. Yaskell To Soon Gim-Chuan, Chua Chiew-See, Pham Than (Lien+Van’s mother) and Ulla and Anna In Memory of Miriam Fuchs (baba Gil’s mother)---W.H.S. In Memory of Andrew Hoff---S.H.Y. To interrupt His Yellow Plan The Sun does not allow Caprices of the Atmosphere – And even when the Snow Heaves Balls of Specks, like Vicious Boy Directly in His Eye – Does not so much as turn His Head Busy with Majesty – ‘Tis His to stimulate the Earth And magnetize the Sea - And bind Astronomy, in place, Yet Any passing by Would deem Ourselves – the busier As the Minutest Bee That rides – emits a Thunder – A Bomb – to justify Emily Dickinson (poem 224. c. 1862) Since people are by nature poorly equipped to register any but short-term changes, it is not surprising that we fail to notice slower changes in either climate or the sun. John A. Eddy, The New Solar Physics (1977-78) Foreword By E. N. Parker In this time of global warming we are impelled by both the anticipated dire consequences and by scientific curiosity to investigate the factors that drive the climate. Climate has fluctuated strongly and abruptly in the past, with ice ages and interglacial warming as the long term extremes. Historical research in the last decades has shown short term climatic transients to be a frequent occurrence, often imposing disastrous hardship on the afflicted human populations. -
Chemical Composition of the RS Cvn-Type Star 33 Piscium
Baltic Astronomy, vol. 20, 53–63, 2011 CHEMICAL COMPOSITION OF THE RS CVn-TYPE STAR 33 PISCIUM G. Bariseviˇcius1, G. Tautvaiˇsien˙e1, S. Berdyugina2, Y. Chorniy1 and I. Ilyin3 1 Institute of Theoretical Physics and Astronomy, Vilnius University, Goˇstauto 12, Vilnius, LT-01108, Lithuania 2 Kiepenheuer Institut f¨ur Sonnenphysik, Sch¨oneckstr. 6, D-79104 Freiburg, Germany 3 Astrophysical Institute Potsdam, An der Sternwarte 16, Potsdam D-14482, Germany Received: 2011 March 7; accepted 2011 March 25 Abstract. Abundances of 22 chemical elements, including the key elements and isotopes such as 12C, 13C, N and O, are investigated in the spectrum of 33 Psc, a single-lined RS CVn-type binary of low magnetic activity. The high resolution spectra were observed on the Nordic Optical Telescope and analyzed with the MARCS model atmospheres. The following main parameters have been determined: Teff = 4750 K, log g = 2.8, [Fe/H] = –0.09, [C/Fe] = –0.04, [N/Fe] = 0.23, [O/Fe] = 0.05, C/N = 2.14, 12C/13C = 30, which show the first-dredge-up mixing signatures and no extra-mixing. Key words: stars: RS CVn binaries, abundances – stars: individual (33 Psc = HD 28)) 1. INTRODUCTION This is the third paper in a series dedicated to a detailed study of photospheric abundances in RS CVn stars (Tautvaiˇsien˙eet al. 2010; Bariseviˇcius et al. 2010, hereafter Papers I and II) with the main aim to get the carbon isotope 12C/13C and C/N ratios in these chromospherically active stars. We plan to investigate correlations between the abundance alterations of chemical elements in the atmo- spheres of these stars and their physical macro parameters, such as the speed of rotation and the magnetic field. -
Information Bulletin on Variable Stars
COMMISSIONS AND OF THE I A U INFORMATION BULLETIN ON VARIABLE STARS Nos November July EDITORS L SZABADOS K OLAH TECHNICAL EDITOR A HOLL TYPESETTING K ORI ADMINISTRATION Zs KOVARI EDITORIAL BOARD L A BALONA M BREGER E BUDDING M deGROOT E GUINAN D S HALL P HARMANEC M JERZYKIEWICZ K C LEUNG M RODONO N N SAMUS J SMAK C STERKEN Chair H BUDAPEST XI I Box HUNGARY URL httpwwwkonkolyhuIBVSIBVShtml HU ISSN COPYRIGHT NOTICE IBVS is published on b ehalf of the th and nd Commissions of the IAU by the Konkoly Observatory Budap est Hungary Individual issues could b e downloaded for scientic and educational purp oses free of charge Bibliographic information of the recent issues could b e entered to indexing sys tems No IBVS issues may b e stored in a public retrieval system in any form or by any means electronic or otherwise without the prior written p ermission of the publishers Prior written p ermission of the publishers is required for entering IBVS issues to an electronic indexing or bibliographic system to o CONTENTS C STERKEN A JONES B VOS I ZEGELAAR AM van GENDEREN M de GROOT On the Cyclicity of the S Dor Phases in AG Carinae ::::::::::::::::::::::::::::::::::::::::::::::::::: : J BOROVICKA L SAROUNOVA The Period and Lightcurve of NSV ::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::: W LILLER AF JONES A New Very Long Period Variable Star in Norma ::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::::: EA KARITSKAYA VP GORANSKIJ Unusual Fading of V Cygni Cyg X in Early November ::::::::::::::::::::::::::::::::::::::: -
![Arxiv:1808.00476V1 [Astro-Ph.SR] 1 Aug 2018 Big Ae Stars but Not for Several Herbig Be Stars (Fairlamb Et Al](https://docslib.b-cdn.net/cover/2783/arxiv-1808-00476v1-astro-ph-sr-1-aug-2018-big-ae-stars-but-not-for-several-herbig-be-stars-fairlamb-et-al-672783.webp)
Arxiv:1808.00476V1 [Astro-Ph.SR] 1 Aug 2018 Big Ae Stars but Not for Several Herbig Be Stars (Fairlamb Et Al
Astronomy & Astrophysics manuscript no. Vioque_et_al_2018 c ESO 2018 August 3, 2018 Gaia DR2 study of Herbig Ae/Be stars M. Vioque1; 2?, R. D. Oudmaijer1, D. Baines3, I. Mendigutía4, and R. Pérez-Martínez2 1 School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK. 2 Ingeniería de Sistemas para la Defensa de España (Isdefe), XMM/Newton Science Operations Centre, ESA-ESAC Campus, PO Box 78, 28691 Villanueva de la Cañada, Madrid, Spain. 3 Quasar Science Resources for ESA-ESAC, ESAC Science Data Center, PO Box 78, 28691 Villanueva de la Cañada, Madrid, Spain. 4 Centro de Astrobiología (CSIC-INTA), Departamento de Astrofísica, ESA-ESAC Campus, PO Box 78, 28691 Villanueva de la Cañada, Madrid, Spain. Accepted for publication in Astronomy & Astrophysics. ABSTRACT Aims. We use Gaia Data Release 2 (DR2) to place 252 Herbig Ae/Be stars in the HR diagram and investigate their characteristics and properties. Methods. For all known Herbig Ae/Be stars with parallaxes in Gaia DR2, we collected their atmospheric parameters and photometric and extinction values from the literature. To these data we added near- and mid-infrared photometry, collected Hα emission line properties such as equivalent widths and line profiles, and their binarity status. In addition, we developed a photometric variability indicator from Gaia’s DR2 information. Results. We provide masses, ages, luminosities, distances, photometric variabilities and infrared excesses homogeneously derived for the most complete sample of Herbig Ae/Be stars to date. We find that high mass stars have a much smaller infrared excess and have much lower optical variabilities compared to lower mass stars, with the break at around 7M .Hα emission is generally correlated with infrared excess, with the correlation being stronger for infrared emission at wavelengths tracing the hot dust closest to the star. -
Sky-High 2009
Sky-High 2009 Total Solar Eclipse, 29th March 2006 The 17th annual guide to astronomical phenomena visible from Ireland during the year ahead (naked-eye, binocular and beyond) By John O’Neill and Liam Smyth Published by the Irish Astronomical Society € 5 P.O. Box 2547, Dublin 14, Ireland. e-mail: [email protected] www.irishastrosoc.org Page 1 Foreword Contents 3 Your Night Sky Primer We send greetings to all fellow astronomers and welcome them to this, the seventeenth edition of 5 Sky Diary 2009 Sky-High. 8 Phases of Moon; Sunrise and Sunset in 2009 We thank the following contributors for their 9 The Planets in 2009 articles: Patricia Carroll, John Flannery and James O’Connor. The remaining material was written by 12 Eclipses in 2009 the editors John O’Neill and Liam Smyth. The Gal- 14 Comets in 2009 lery has images and drawings by Society members. The times of sunrise etc. are from SUNRISE by J. 16 Meteors Showers in 2009 O’Neill. 17 Asteroids in 2009 We are always glad to hear what you liked, or 18 Variable Stars in 2009 what you would like to have included in Sky-High. If we have slipped up on any matter of fact, let us 19 A Brief Trip Southwards know. We can put a correction in future issues. And if you have any problem with understanding 20 Deciphering Star Names the contents or would like more information on 22 Epsilon Aurigae – a long period variable any topic, feel free to contact us at the Society e- mail address [email protected]. -
Sodium and Potassium Signatures Of
Sodium and Potassium Signatures of Volcanic Satellites Orbiting Close-in Gas Giant Exoplanets Apurva Oza, Robert Johnson, Emmanuel Lellouch, Carl Schmidt, Nick Schneider, Chenliang Huang, Diana Gamborino, Andrea Gebek, Aurelien Wyttenbach, Brice-Olivier Demory, et al. To cite this version: Apurva Oza, Robert Johnson, Emmanuel Lellouch, Carl Schmidt, Nick Schneider, et al.. Sodium and Potassium Signatures of Volcanic Satellites Orbiting Close-in Gas Giant Exoplanets. The Astro- physical Journal, American Astronomical Society, 2019, 885 (2), pp.168. 10.3847/1538-4357/ab40cc. hal-02417964 HAL Id: hal-02417964 https://hal.sorbonne-universite.fr/hal-02417964 Submitted on 18 Dec 2019 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. The Astrophysical Journal, 885:168 (19pp), 2019 November 10 https://doi.org/10.3847/1538-4357/ab40cc © 2019. The American Astronomical Society. Sodium and Potassium Signatures of Volcanic Satellites Orbiting Close-in Gas Giant Exoplanets Apurva V. Oza1 , Robert E. Johnson2,3 , Emmanuel Lellouch4 , Carl Schmidt5 , Nick Schneider6 , Chenliang Huang7 , Diana Gamborino1 , Andrea Gebek1,8 , Aurelien Wyttenbach9 , Brice-Olivier Demory10 , Christoph Mordasini1 , Prabal Saxena11, David Dubois12 , Arielle Moullet12, and Nicolas Thomas1 1 Physikalisches Institut, Universität Bern, Bern, Switzerland; [email protected] 2 Engineering Physics, University of Virginia, Charlottesville, VA 22903, USA 3 Physics, New York University, 4 Washington Place, New York, NY 10003, USA 4 LESIA–Observatoire de Paris, CNRS, UPMC Univ. -
![Arxiv:0908.2624V1 [Astro-Ph.SR] 18 Aug 2009](https://docslib.b-cdn.net/cover/1870/arxiv-0908-2624v1-astro-ph-sr-18-aug-2009-1111870.webp)
Arxiv:0908.2624V1 [Astro-Ph.SR] 18 Aug 2009
Astronomy & Astrophysics Review manuscript No. (will be inserted by the editor) Accurate masses and radii of normal stars: Modern results and applications G. Torres · J. Andersen · A. Gim´enez Received: date / Accepted: date Abstract This paper presents and discusses a critical compilation of accurate, fun- damental determinations of stellar masses and radii. We have identified 95 detached binary systems containing 190 stars (94 eclipsing systems, and α Centauri) that satisfy our criterion that the mass and radius of both stars be known to ±3% or better. All are non-interacting systems, so the stars should have evolved as if they were single. This sample more than doubles that of the earlier similar review by Andersen (1991), extends the mass range at both ends and, for the first time, includes an extragalactic binary. In every case, we have examined the original data and recomputed the stellar parameters with a consistent set of assumptions and physical constants. To these we add interstellar reddening, effective temperature, metal abundance, rotational velocity and apsidal motion determinations when available, and we compute a number of other physical parameters, notably luminosity and distance. These accurate physical parameters reveal the effects of stellar evolution with un- precedented clarity, and we discuss the use of the data in observational tests of stellar evolution models in some detail. Earlier findings of significant structural differences between moderately fast-rotating, mildly active stars and single stars, ascribed to the presence of strong magnetic and spot activity, are confirmed beyond doubt. We also show how the best data can be used to test prescriptions for the subtle interplay be- tween convection, diffusion, and other non-classical effects in stellar models. -
Planet Formation Phil Armitage
Planet Formation Phil Armitage Colorado è Stony Brook / Simons CCA overview • stone age planet formation – formation of planetary systems from a smooth radial distribution of km-scale planetesimals embedded in gas, with no migration • planetesimal • planetesimals formation or pebbles? • migration • gas accretion How do we form observed systems? Is there a timing problem? classical planet formation Adopt effective initial conditions: radially smooth distribution of small (100m – km) planetesimals embedded in gas, which acts to damp {e,i} but does not cause migration • growth phases: runaway, oligarchic final assembly / giant impacts • if fast enough final outcome is ~determined by stability M 1/3 r = p a Hill 3M ✓ ⇤ ◆ 1/4 tinstability = f(∆a/Mp ) • collisions make a small-N system more stable classical planet formation t / Myr 100 Ratio of collisions to scatterings is 10 f(vK / vesc), favors collisions for MSun at a ~ AU and less 1 “in situ” formation e 1 AU 2 AU 3 AU • disk with a few ME / AU at 1 AU will work • requirement of stability can hide a multitude of sins • many important but lesser constraints (small mass of Mars…) classical planet formation quasi-static envelope extends to rHill, rBondi core grows from accretion of planetesimals cooling is limited by grain opacity in radiative zone in the envelope “success” requires reaching Menv ~ Mcore ~ 5-20 ME within gas disk lifetime possible at few AU if the gravitational focusing factor 2 [1 + (vesc / σ) ] is large (small planetesimals) and κ low what’s wrong with this story? • major -
The Ephemeris Encyclopedia Galactica: Unexplored Space
The Ephemeris Encyclopedia Galactica: Unexplored Space Sample file 2 Copyright © 2015 Nomadic Delirium Press http://www.nomadicdeliriumpress.com All rights reserved. No part of this book may be reproduced or transmitted in any form or by any means, electronic, mechanical, including photocopying, recording, or by any informational storage and retrieval system, without the written consent of the publisher, except by a reviewer who wishes to quote brief passages in connection with a review written for inclusion in a magazine, newspaper, website, broadcast, etc. Nomadic Delirium Press Aurora, Colorado Sample file 3 INTRODUCTION TO SECTOR FORTY-TWO Welcome to The Ephemeris Encyclopedia Galactica: Sector Forty-Two, an examination of a sector of what is known as “deep space”. The version you are reading is in the Human’s lingua franca. If you are not human, and would like to read it in your species’ native tongue, please consult a data bank on one of your species’ planets and download the appropriate version. Since it’s assumed that you are human, the text in this volume of the Encyclopedia is laid out in a way that will be easy for you to understand. Each star system is listed by the name that your species calls it, and the listings are arranged in order from the closest to your home system out to the ones farthest from your home system. All distances are listed in light years, since that’s what you use on your homeworld. Since this volume of the Encyclopedia is written for humans, it might be safe to assume that you already know all of the details of these systems, but just in case, we’re including everything we can here. -
GEORGE HERBIG and Early Stellar Evolution
GEORGE HERBIG and Early Stellar Evolution Bo Reipurth Institute for Astronomy Special Publications No. 1 George Herbig in 1960 —————————————————————– GEORGE HERBIG and Early Stellar Evolution —————————————————————– Bo Reipurth Institute for Astronomy University of Hawaii at Manoa 640 North Aohoku Place Hilo, HI 96720 USA . Dedicated to Hannelore Herbig c 2016 by Bo Reipurth Version 1.0 – April 19, 2016 Cover Image: The HH 24 complex in the Lynds 1630 cloud in Orion was discov- ered by Herbig and Kuhi in 1963. This near-infrared HST image shows several collimated Herbig-Haro jets emanating from an embedded multiple system of T Tauri stars. Courtesy Space Telescope Science Institute. This book can be referenced as follows: Reipurth, B. 2016, http://ifa.hawaii.edu/SP1 i FOREWORD I first learned about George Herbig’s work when I was a teenager. I grew up in Denmark in the 1950s, a time when Europe was healing the wounds after the ravages of the Second World War. Already at the age of 7 I had fallen in love with astronomy, but information was very hard to come by in those days, so I scraped together what I could, mainly relying on the local library. At some point I was introduced to the magazine Sky and Telescope, and soon invested my pocket money in a subscription. Every month I would sit at our dining room table with a dictionary and work my way through the latest issue. In one issue I read about Herbig-Haro objects, and I was completely mesmerized that these objects could be signposts of the formation of stars, and I dreamt about some day being able to contribute to this field of study.