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August 10Th 2019 August 2019 7:00Pm at the Herrett Center for Arts & Science College of Southern Idaho
Snake River Skies The Newsletter of the Magic Valley Astronomical Society www.mvastro.org Membership Meeting MVAS President’s Message August 2019 Saturday, August 10th 2019 7:00pm at the Herrett Center for Arts & Science College of Southern Idaho. Colleagues, Public Star Party follows at the I hope you found the third week of July exhilarating. The 50th Anniversary of the first Centennial Observatory moon landing was the common theme. I capped my observance by watching the C- SPAN replay of the CBS broadcast. It was not only exciting to watch the landing, but Club Officers to listen to Walter Cronkite and Wally Schirra discuss what Neil Armstrong and Buzz Robert Mayer, President Aldrin was relaying back to us. It was fascinating to hear what we have either accepted or rejected for years come across as something brand new. Hearing [email protected] Michael Collins break in from his orbit above in the command module also reminded me of the major role he played and yet others in the past have often overlooked – Gary Leavitt, Vice President fortunately, he is now receiving the respect he deserves. If you didn’t catch that, [email protected] then hopefully you caught some other commemoration, such as Turner Classic Movies showing For All Mankind, a spellbinding documentary of what it was like for Dr. Jay Hartwell, Secretary all of the Apollo astronauts who made it to the moon. Jim Tubbs, Treasurer / ALCOR For me, these moments of commemoration made reading the moon landing’s [email protected] anniversary issue from the Association of Lunar and Planetary Observers (ALPO) 208-404-2999 come to life as they wrote about the features these astronauts were examining – including the little craters named after the three astronauts. -
Spring Fever Strikes
The MARCH 2002 DENVER OBSERVER Newsletter of the Denver Astronomical Society One Mile Nearer the Stars How Many in One Night?? Gearing up for the Messier Marathon? Those folks who are new to astronomy may not yet be able to relate to the sheer joy of braving the early-spring temperatures (brrrrr) for a full night (and morning—I’m talking dusk to dawn, here) of observing some of the most beautiful objects in the heavens. Why now? Because for only a few weeks during the year is it possible to see all of the Messier objects in one night. Astronomers will dig in their heels and tripods, get out the star charts (See Page 7), and knock off one object after the next. Some people actually catalog 70 of the available 110 targets and submit their achievements to the Astronomical League for the coveted Messier Certificate. Others just like to look at the beautiful celestial wonders like the one in the photo to the left. Either way, get out to the The Pleaides (M45) DSS on the weekend of the 15th and enjoy Image © Joe Gafford, 2002 the views!—PK Spring Fever Strikes President’s Corner .......... 2 MARCH SKIES 2002 f you’ve been reading your astronomy magazines, you know that by month’s Schedule of Events ......... 2 Iend, four naked-eye planets will grace the night skies. Jupiter is the main show-stopper but Saturn, Mars, and finally Venus will sparkle for all, moon or no moon. Remember that a Officers ......................... 2 little high-cloud haze can be good for telescopic planet observations. -
April 2020 Page 1 of 11
Pretoria Centre ASSA April 2020 Page 1 of 11 NEWSLETTER APRIL 2020 Dear member In the light of the current situation and based upon advice from a virologist at one of the leading pathology laboratories, we regret to have to cancel the March and April viewing evenings and meetings of the Pretoria Centre of ASSA. The situation will be reviewed in time for the May activities and members will be informed of any changes. This decision was not taken lightly, but we believe the health of our members is important and we would not like to be the reason one of our members should fall victim to the virus. We apologize for the inconvenience and trust the skies will be clear wherever you wish to spend time under the stars. Bosman Olivier Chairman TABLE OF CONTENTS Astronomy-related articles on the Internet 2 Astronomy basics: Galaxies 3 Feature of the month: Biggest explosion seen since the Big Bang 3 Astronomy-related images and video clips on the Internet 3 Astronomy basics: Galaxies 3 Observing: A different star cluster - by Magda Streicher 4 NOTICE BOARD 5 Pretoria Centre committee 5 Open Star Clusters with Superimposed Planetary Nebulae: 6 M46/NGC 2438 and NGC 2818/2818A Pretoria Centre ASSA April 2020 Page 2 of 11 Astronomy-related articles on the Internet Is bright Comet ATLAS disintegrating? https://earthsky.org/space/how-to-see-bright- comet-c-2019-y4-atlas?utm_source=EarthSky+News&utm_campaign=11f7198ca6- EMAIL_CAMPAIGN_2018_02_02_COPY_01&utm_medium=email&utm_term=0_c64394 5d79-11f7198ca6-394671529 Meet the giant exoplanet where it rains iron. The temperatures on the day side of giant exoplanet WASP-76b are scorching, high enough for metals to be vapourized. -
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. -
Spatial Distribution of Galactic Globular Clusters: Distance Uncertainties and Dynamical Effects
Juliana Crestani Ribeiro de Souza Spatial Distribution of Galactic Globular Clusters: Distance Uncertainties and Dynamical Effects Porto Alegre 2017 Juliana Crestani Ribeiro de Souza Spatial Distribution of Galactic Globular Clusters: Distance Uncertainties and Dynamical Effects Dissertação elaborada sob orientação do Prof. Dr. Eduardo Luis Damiani Bica, co- orientação do Prof. Dr. Charles José Bon- ato e apresentada ao Instituto de Física da Universidade Federal do Rio Grande do Sul em preenchimento do requisito par- cial para obtenção do título de Mestre em Física. Porto Alegre 2017 Acknowledgements To my parents, who supported me and made this possible, in a time and place where being in a university was just a distant dream. To my dearest friends Elisabeth, Robert, Augusto, and Natália - who so many times helped me go from "I give up" to "I’ll try once more". To my cats Kira, Fen, and Demi - who lazily join me in bed at the end of the day, and make everything worthwhile. "But, first of all, it will be necessary to explain what is our idea of a cluster of stars, and by what means we have obtained it. For an instance, I shall take the phenomenon which presents itself in many clusters: It is that of a number of lucid spots, of equal lustre, scattered over a circular space, in such a manner as to appear gradually more compressed towards the middle; and which compression, in the clusters to which I allude, is generally carried so far, as, by imperceptible degrees, to end in a luminous center, of a resolvable blaze of light." William Herschel, 1789 Abstract We provide a sample of 170 Galactic Globular Clusters (GCs) and analyse its spatial distribution properties. -
Luminosities and Mass-Loss Rates of SMC and LMC AGB Stars and Red Supergiants Dependence of Mass Loss on Metallicity, the Amount of Dust Pro- PAH Emission1
Astronomy & Astrophysics manuscript no. art63 c ESO 2018 November 10, 2018 Luminosities and mass-loss rates of SMC and LMC AGB stars and Red Supergiants ⋆ M. A. T. Groenewegen1, G. C. Sloan2, I. Soszy´nski3, and E. A. Petersen4,5 1 Koninklijke Sterrenwacht van Belgi¨e, Ringlaan 3, B–1180 Brussels, Belgium e-mail: [email protected] 2 Cornell University, Astronomy Department, Ithaca, NY 14853-6801, USA 3 Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa, Poland 4 University of Nebraska, Department of Physics and Astronomy, Lincoln, NE 68588, USA 5 NSF REU Research Assistant, Cornell University, Astronomy Department, Ithaca, NY 14853-6801, USA received: 2009, accepted: 20-08-2009 ABSTRACT Context Mass loss is one of the fundamental properties of Asymptotic Giant Branch (AGB) stars, and through the enrichment of the interstellar medium, AGB stars are key players in the life cycle of dust and gas in the universe. However, a quantitative understanding of the mass-loss process is still largely lacking, particularly its dependence on metallicity. Aims To investigate the relation between mass loss, luminosity and pulsation period for a large sample of evolved stars in the Small and Large Magellanic Cloud. Results Dust radiative transfer models are presented for 101 carbon stars and 86 oxygen-rich evolved stars in the Magellanic Clouds for which 5–35 µm Spitzer IRS spectra are available. The spectra are complemented with available optical and infrared photometry to construct the spectral energy distribution. A minimisation procedure is used to fit luminosity, mass-loss rate and dust temperature at the inner radius. -
Arxiv:0809.1275V2
How eccentric orbital solutions can hide planetary systems in 2:1 resonant orbits Guillem Anglada-Escud´e1, Mercedes L´opez-Morales1,2, John E. Chambers1 [email protected], [email protected], [email protected] ABSTRACT The Doppler technique measures the reflex radial motion of a star induced by the presence of companions and is the most successful method to detect ex- oplanets. If several planets are present, their signals will appear combined in the radial motion of the star, leading to potential misinterpretations of the data. Specifically, two planets in 2:1 resonant orbits can mimic the signal of a sin- gle planet in an eccentric orbit. We quantify the implications of this statistical degeneracy for a representative sample of the reported single exoplanets with available datasets, finding that 1) around 35% percent of the published eccentric one-planet solutions are statistically indistinguishible from planetary systems in 2:1 orbital resonance, 2) another 40% cannot be statistically distinguished from a circular orbital solution and 3) planets with masses comparable to Earth could be hidden in known orbital solutions of eccentric super-Earths and Neptune mass planets. Subject headings: Exoplanets – Orbital dynamics – Planet detection – Doppler method arXiv:0809.1275v2 [astro-ph] 25 Nov 2009 Introduction Most of the +300 exoplanets found to date have been discovered using the Doppler tech- nique, which measures the reflex motion of the host star induced by the planets (Mayor & Queloz 1995; Marcy & Butler 1996). The diverse characteristics of these exoplanets are somewhat surprising. Many of them are similar in mass to Jupiter, but orbit much closer to their 1Carnegie Institution of Washington, Department of Terrestrial Magnetism, 5241 Broad Branch Rd. -
Astronomy Magazine Special Issue
γ ι ζ γ δ α κ β κ ε γ β ρ ε ζ υ α φ ψ ω χ α π χ φ γ ω ο ι δ κ α ξ υ λ τ μ β α σ θ ε β σ δ γ ψ λ ω σ η ν θ Aι must-have for all stargazers η δ μ NEW EDITION! ζ λ β ε η κ NGC 6664 NGC 6539 ε τ μ NGC 6712 α υ δ ζ M26 ν NGC 6649 ψ Struve 2325 ζ ξ ATLAS χ α NGC 6604 ξ ο ν ν SCUTUM M16 of the γ SERP β NGC 6605 γ V450 ξ η υ η NGC 6645 M17 φ θ M18 ζ ρ ρ1 π Barnard 92 ο χ σ M25 M24 STARS M23 ν β κ All-in-one introduction ALL NEW MAPS WITH: to the night sky 42,000 more stars (87,000 plotted down to magnitude 8.5) AND 150+ more deep-sky objects (more than 1,200 total) The Eagle Nebula (M16) combines a dark nebula and a star cluster. In 100+ this intense region of star formation, “pillars” form at the boundaries spectacular between hot and cold gas. You’ll find this object on Map 14, a celestial portion of which lies above. photos PLUS: How to observe star clusters, nebulae, and galaxies AS2-CV0610.indd 1 6/10/10 4:17 PM NEW EDITION! AtlAs Tour the night sky of the The staff of Astronomy magazine decided to This atlas presents produce its first star atlas in 2006. -
A Basic Requirement for Studying the Heavens Is Determining Where In
Abasic requirement for studying the heavens is determining where in the sky things are. To specify sky positions, astronomers have developed several coordinate systems. Each uses a coordinate grid projected on to the celestial sphere, in analogy to the geographic coordinate system used on the surface of the Earth. The coordinate systems differ only in their choice of the fundamental plane, which divides the sky into two equal hemispheres along a great circle (the fundamental plane of the geographic system is the Earth's equator) . Each coordinate system is named for its choice of fundamental plane. The equatorial coordinate system is probably the most widely used celestial coordinate system. It is also the one most closely related to the geographic coordinate system, because they use the same fun damental plane and the same poles. The projection of the Earth's equator onto the celestial sphere is called the celestial equator. Similarly, projecting the geographic poles on to the celest ial sphere defines the north and south celestial poles. However, there is an important difference between the equatorial and geographic coordinate systems: the geographic system is fixed to the Earth; it rotates as the Earth does . The equatorial system is fixed to the stars, so it appears to rotate across the sky with the stars, but of course it's really the Earth rotating under the fixed sky. The latitudinal (latitude-like) angle of the equatorial system is called declination (Dec for short) . It measures the angle of an object above or below the celestial equator. The longitud inal angle is called the right ascension (RA for short). -
LIST of PUBLICATIONS Aryabhatta Research Institute of Observational Sciences ARIES (An Autonomous Scientific Research Institute
LIST OF PUBLICATIONS Aryabhatta Research Institute of Observational Sciences ARIES (An Autonomous Scientific Research Institute of Department of Science and Technology, Govt. of India) Manora Peak, Naini Tal - 263 129, India (1955−2020) ABBREVIATIONS AA: Astronomy and Astrophysics AASS: Astronomy and Astrophysics Supplement Series ACTA: Acta Astronomica AJ: Astronomical Journal ANG: Annals de Geophysique Ap. J.: Astrophysical Journal ASP: Astronomical Society of Pacific ASR: Advances in Space Research ASS: Astrophysics and Space Science AE: Atmospheric Environment ASL: Atmospheric Science Letters BA: Baltic Astronomy BAC: Bulletin Astronomical Institute of Czechoslovakia BASI: Bulletin of the Astronomical Society of India BIVS: Bulletin of the Indian Vacuum Society BNIS: Bulletin of National Institute of Sciences CJAA: Chinese Journal of Astronomy and Astrophysics CS: Current Science EPS: Earth Planets Space GRL : Geophysical Research Letters IAU: International Astronomical Union IBVS: Information Bulletin on Variable Stars IJHS: Indian Journal of History of Science IJPAP: Indian Journal of Pure and Applied Physics IJRSP: Indian Journal of Radio and Space Physics INSA: Indian National Science Academy JAA: Journal of Astrophysics and Astronomy JAMC: Journal of Applied Meterology and Climatology JATP: Journal of Atmospheric and Terrestrial Physics JBAA: Journal of British Astronomical Association JCAP: Journal of Cosmology and Astroparticle Physics JESS : Jr. of Earth System Science JGR : Journal of Geophysical Research JIGR: Journal of Indian -
The Density and Shock Characteristics of NGC 2818?
ASTRONOMY & ASTROPHYSICS DECEMBER II 1998, PAGE 381 SUPPLEMENT SERIES Astron. Astrophys. Suppl. Ser. 133, 381–386 (1998) The density and shock characteristics of NGC 2818? J.P. Phillips1 and L. Cuesta2 1 Instituto de Astronomia y Meteorologia, Avenida Vallarta 2602, Col. Arcos Vallarta, C.P. 44130 Guadalajara, Jalisco, Mexico e-mail: [email protected] 2 Instituto de Astrofisica de Canarias, La Laguna, Tenerife, Spain e-mail: [email protected] Received January 26; accepted June 26, 1998 Abstract. We report the results of narrow band imaging It is however unusual among such nebulae in being located of the bipolar outflow source NGC 2818 in transitions of within a Population I galactic cluster of the same name; its [NII], [OIII], [SII], and HI. As a consequence, we are able position, extinction and radial velocity are all consistent to assess the overall excitation properties of the shell, and with cluster membership (Tifft et al. 1972). determine that line ratios towards the nebular periphery This should, in turn, permit a more precise analysis of are anomalous, and characteristic of planar shocks with the source physical characteristics, since cluster distances −1 velocity Vs ≥ 110 km s . Pre-shock densities are likely to can be rather precisely determined (in principle) given a 2 3 −3 be modest, and of order 10 <np <10 cm . combination of stellar photometry and evolutionary the- The [SII] imaging is further used to derive a fully- ory. In reality, it appears that estimates for the distance of sampled map of electron density, whence it is clear NGC 2818 have varied widely over the years, from 5 kpc that the density structure is rather complex and re- (Shapley 1930), to 1.44 kpc (Barkhatova 1950), 3.2 and lated to various features within the excitation maps. -
The Role of Evolutionary Age and Metallicity in the Formation of Classical Be Circumstellar Disks 11
< * - - *" , , Source of Acquisition NASA Goddard Space Flight Center THE ROLE OF EVOLUTIONARY AGE AND METALLICITY IN THE FORMATION OF CLASSICAL BE CIRCUMSTELLAR DISKS 11. ASSESSING THE TRUE NATURE OF CANDIDATE DISK SYSTEMS J.P. WISNIEWSKI"~'~,K.S. BJORKMAN~'~,A.M. MAGALH~ES~",J.E. BJORKMAN~,M.R. MEADE~, & ANTONIOPEREYRA' Draft version November 27, 2006 ABSTRACT Photometric 2-color diagram (2-CD) surveys of young cluster populations have been used to identify populations of B-type stars exhibiting excess Ha emission. The prevalence of these excess emitters, assumed to be "Be stars". has led to the establishment of links between the onset of disk formation in classical Be stars and cluster age and/or metallicity. We have obtained imaging polarization observations of six SMC and six LMC clusters whose candidate Be populations had been previously identified via 2-CDs. The interstellar polarization (ISP). associated with these data has been identified to facilitate an examination of the circumstellar environments of these candidate Be stars via their intrinsic ~olarization signatures, hence determine the true nature of these objects. We determined that the ISP associated with the SMC cluster NGC 330 was characterized by a modified Serkowski law with a A,,, of -4500A, indicating the presence of smaller than average dust grains. The morphology of the ISP associated with the LMC cluster NGC 2100 suggests that its interstellar environment is characterized by a complex magnetic field. Our intrinsic polarization results confirm the suggestion of Wisniewski et al. that a substantial number of bona-fide classical Be stars are present in clusters of age 5-8 Myr.