The Ephemeris Encyclopedia Galactica: Unexplored Space
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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 . -
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. -
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]. -
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. -
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. -
X. Bayesian Stellar Parameters and Evolutionary Stages for 372 Giant Stars from the Lick Planet Search?
A&A 616, A33 (2018) Astronomy https://doi.org/10.1051/0004-6361/201833111 & c ESO 2018 Astrophysics Precise radial velocities of giant stars X. Bayesian stellar parameters and evolutionary stages for 372 giant stars from the Lick planet search? Stephan Stock, Sabine Reffert, and Andreas Quirrenbach Landessternwarte, Zentrum für Astronomie der Universität Heidelberg, Königstuhl 12, 69117 Heidelberg, Germany e-mail: [email protected] Received 27 March 2018 / Accepted 4 May 2018 ABSTRACT Context. The determination of accurate stellar parameters of giant stars is essential for our understanding of such stars in general and as exoplanet host stars in particular. Precise stellar masses are vital for determining the lower mass limit of potential substellar companions with the radial velocity method, but also for dynamical modeling of multiplanetary systems and the analysis of planetary evolution. Aims. Our goal is to determine stellar parameters, including mass, radius, age, surface gravity, effective temperature and luminosity, for the sample of giants observed by the Lick planet search. Furthermore, we want to derive the probability of these stars being on the horizontal branch (HB) or red giant branch (RGB), respectively. Methods. We compare spectroscopic, photometric and astrometric observables to grids of stellar evolutionary models using Bayesian inference. Results. We provide tables of stellar parameters, probabilities for the current post-main sequence evolutionary stage, and probability density functions for 372 giants from the Lick planet search. We find that 81% of the stars in our sample are more probably on the HB. In particular, this is the case for 15 of the 16 planet host stars in the sample. -
Venus and Mercury Are Back
FORT WORTH ASTRONOMICAL SOCIETY (est. 1949) NOVEMBER 2011 Venus and Mercury Are Back In This Issue November Club Calendar ... 2 Night Sky Chart ... 3 Cloudy Night Library ... 4 The Gray Cubicle You Want To Work In ... 6 Clues From Ancient Light ... 7 This Month’s Constellation - Pisces ... 8 Image courtesy of science.nasa.gov PRIME FOCUS - FORT WORTH ASTRONOMICAL SOCIETY NOVEMBER 2011 November 2011 Sun Mon Tue Wed Thu Fri Sat 1 2 3 4 5 1st Quarter Moon 11:38pm 6 7 8 9 10 11 12 Day Light Saving Asteroid 2005 Neptune is Full Moon Veterans Day ends at 2am YU55 passes only stationary 2:16pm 202,000mi from Earth 13 14 15 16 17 18 19 Leonid meteor Last Quarter shower peaks Moon 9:09am FWAS Monthly Meeting 20 21 22 23 24 25 26 Thanksgiving Day New Moon 12:10am Mercury is stationary 27 28 29 30 2 PRIME FOCUS - FORT WORTH ASTRONOMICAL SOCIETY NOVEMBER 2011 November Night Sky November 15, 2011 @ 10:00pm CST Sky chart coutesy of Chris Peat and http://www.heavens-above.com/ Planet Viewing This Month Mercury is in the western evening sky and remains about 20 from Venus for the first half of the month. Venus sits low in the southwestern evening twilight. Mars is mostly out of the picture but can be spotted in Leo early in the morning. Jupiter has just passed opposition and still traverses the sky all evening, setting near dawn. Although the angle of ecliptic favors the Northern Hemisphere, Saturn can be seen in the pre-dawn sky, in Virgo. -
Herbig Ae/Be Stars the Missing Link in Star Formation
Herbig Ae/Be stars The missing link in star formation Program and Abstract Book Santiago, Chile, April 7-11, 2014 The ESO 2014 Herbig Ae/Be workshop will take place in commemoration of the life and works of George H. Herbig (January 2, 1920 – October 12, 2013). Program Monday, April 7 Time Speaker Title 08:30{08:40 W.J. de Wit Welcome 08:40{09:20 R. Waters Herbig Ae/Be stars in perspective \Overture": Star formation 09:20{10:00 K. Kratter Introduction to the theory of star formation 10:00{10:40 M. Beltran Observational perspective of the youngest phases of intermediate mass stars 10:40{11:10 Coffee Break SESSION 1: Inner disk - accretion tracers dynamics 11:10{11:50 S. Brittain High resolution spectroscopy and spectro-astrometry of HAeBes 11:50{12:10 J. Ilee Investigating inner gaseous discs around Herbig Ae/Be stars 12:10{12:30 J. Fairlamb Large Spectroscopic Investigation of Over 90 Herbig Ae/Be Objects with X-Shooter 12:30{12:50 Poster presentations (1st half) 12:50{14:30 Lunch 14:30{15:10 C. Dougados Accretion-ejection processes in Herbig Ae/Be stars 15:10{15:30 A. Aarnio Herbig Ae/Be spectral line variability 15:30{15:50 P. Abrah´am´ Time-variable phenomena in Herbig Ae/Be stars 15:50{16:10 Poster presentations (2nd half) 16:10{16:40 Poster session with tea 16:40{17:00 C. Schneider High energy emission from the HD 163296 jet: Clues to magnetic jet launching 17:00{17:20 I. -
Eao Submillimetre Futures Paper Series, 2019
EAO SUBMILLIMETRE FUTURES PAPER SERIES, 2019 The East Asian Observatory∗ James Clerk Maxwell Telescope 660 N. A‘ohok¯ u¯ Place, Hilo, Hawai‘i, USA, 96720 1 About This Series Submillimetre astronomy is an active and burgeoning field that is poised to answer some of the most pressing open questions about the universe. The James Clerk Maxwell Telescope, operated by the East Asian Observatory, is at the forefront of discovery as it is the largest single-dish submillimetre telescope in the world. Situated at an altitude of 4,092 metres on Maunakea, Hawai‘i, USA, the facility capitalises on the 850 µm observing window that offers crucial insights into the cold dust that forms stars and galaxies. In 1997, the Submillimetre Common User Bolometer Array (SCUBA) was commissioned, allowing astronomers to detect the furthest galaxies ever recorded (so-called SCUBA galaxies) and develop our understanding of the earliest stages of star formation. Since 2011, its successor, SCUBA-2, has revolutionised submillimetre wavelength surveys by mapping the sky hundreds of times faster than SCUBA. The extensive data collected spans a wealth of astronomy sub-fields and has inspired world-wide collaborations and innovative analysis methods for nearly a decade. Building on the successes of these instruments, the East Asian Observatory is constructing a third generation 850 µm wide-field camera with intrinsic polarisation capabilities for deployment on the James Clerk Maxwell Telescope. In May, 2019, the “EAO Submillimetre Futures” meeting was held in Nanjing, China to discuss the science drivers of future instrumentation and the needs of the submillimetre astronomy community. A central focus of the meeting was the new 850 µm camera. -
Extended Envelopes Around Galactic Cepheids. Iii. Y Ophiuchi and Persei from Near-Infrared Interferometry with Chara/Fluor
The Astrophysical Journal, 664:1093Y1101, 2007 August 1 # 2007. The American Astronomical Society. All rights reserved. Printed in U.S.A. EXTENDED ENVELOPES AROUND GALACTIC CEPHEIDS. III. Y OPHIUCHI AND PERSEI FROM NEAR-INFRARED INTERFEROMETRY WITH CHARA/FLUOR Antoine Me´rand Center for High Angular Resolution Astronomy, Georgia State University, PO Box 3965, Atlanta, GA 30302-3965; [email protected] Jason P. Aufdenberg Physical Sciences Department, Embry-Riddle Aeronautical University, Daytona Beach, FL 32114 Pierre Kervella and Vincent Coude´ du Foresto LESIA, UMR 8109, Observatoire de Paris, 5 place Jules Janssen, 92195 Meudon, France and Theo A. ten Brummelaar, Harold A. McAlister, Laszlo Sturmann, Judit Sturmann, and Nils H. Turner Center for High Angular Resolution Astronomy, Georgia State University, PO Box 3965, Atlanta, GA 30302-3965 Received 2007 February 23; accepted 2007 April 2 ABSTRACT Unbiased angular diameter measurements are required for accurate distances to Cepheids using the interferometric Baade-Wesselink method (IBWM). The precision of this technique is currently limited by interferometric measure- ments at the 1.5% level. At this level, the center-to-limb darkening (CLD) and the presence of circumstellar envelopes (CSE) seem to be the two main sources of bias. The observations we performed aim at improving our knowledge of the interferometric visibility profile of Cepheids. In particular, we assess the systematic presence of CSE around Cepheids in order determine accurate distances with the IBWM free from CSE biased angular diameters. We ob- served a Cepheid (Y Oph) for which the pulsation is well resolved and a nonpulsating yellow supergiant ( Per) using long-baseline near-infrared interferometry. -
1903Aj 23 . . . 22K 22 the Asteojsomic Al
22 THE ASTEOJSOMIC AL JOUENAL. Nos- 531-532 22K . Taking into account the smallness of the weights in- concerned. Through the use of these tables the positions . volved, the individual differences which make up the and motions of many stars not included in the present 23 groups in the preceding table agree^very well. catalogue can be brought into systematic harmony with it, and apparently without materially less accuracy for the in- dividual stars than could be reached by special compu- Tables of Systematic Correction for N2 and A. tations for these stars in conformity with the system of B. 1903AJ The results of the foregoing comparisons. have been This is especially true of the star-places computed by utilized to form tables of systematic corrections for ISr2, An, Dr. Auwers in the catalogues, Ai and As. As will be seen Ai and As. In right-ascension no distinction is necessary by reference to the catalogue the positions and motions of between the various catalogues published by Dr. Auwers, south polar stars taken from N2 agree better with the beginning with the Fundamental-G at alo g ; but in decli- results of this investigation than do those taken from As, nation the distinction between the northern, intermediate, which, in turn, are quoted from the Cape Catalogue for and southern catalogues must be preserved, so far as is 1890. SYSTEMATIC COBEECTIOEB : CEDEE OF DECLINATIONS. Eight-Ascensions ; Cokrections, ¿las and 100z//xtf. Declinations; Corrections, Æs and IOOzZ/x^. B — ISa B —A B —N2 B —An B —Ai âas 100 â[is âas 100 âgô âSs 100 -
November 2020 BRAS Newsletter
A Mars efter Lowell's Glober ca. 1905-1909”, from Percival Lowell’s maps; National Maritime Museum, Greenwich, London (see Page 6) Monthly Meeting November 9th at 7:00 PM, via Jitsi (Monthly meetings are on 2nd Mondays at Highland Road Park Observatory, temporarily during quarantine at meet.jit.si/BRASMeets). GUEST SPEAKER: Chuck Allen from the Astronomical League will speak about The Cosmic Distance Ladder, which explores the historical advancement of distance determinations in astronomy. What's In This Issue? President’s Message Member Meeting Minutes Business Meeting Minutes Outreach Report Asteroid and Comet News Light Pollution Committee Report Globe at Night Member’s Corner – John Nagle ALPO 2020 Conference Astro-Photos by BRAS Members - MARS Messages from the HRPO REMOTE DISCUSSION Solar Viewing Edge of Night Natural Sky Conference Recent Entries in the BRAS Forum Observing Notes: Pisces – The Fishes 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 24 November 2020 President’s Message Welcome to the home stretch for 2020. The nights are starting earlier and earlier as the weather becomes more and more comfortable and all of our old favorites of the fall and winter skies really start finding their places right where they belong. October was a busy month for us, with several big functions at the Observatory, including two oppositions and two more all night celebrations. By comparison, November is looking fairly calm, the big focus there is going to be our third annual Natural Sky Conference on the 13th, which I’m encouraging people who care about the state of light pollution in our city and the surrounding area to get involved in.