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Planetary Nebulae
Planetary Nebulae A planetary nebula is a kind of emission nebula consisting of an expanding, glowing shell of ionized gas ejected from old red giant stars late in their lives. The term "planetary nebula" is a misnomer that originated in the 1780s with astronomer William Herschel because when viewed through his telescope, these objects appeared to him to resemble the rounded shapes of planets. Herschel's name for these objects was popularly adopted and has not been changed. They are a relatively short-lived phenomenon, lasting a few tens of thousands of years, compared to a typical stellar lifetime of several billion years. The mechanism for formation of most planetary nebulae is thought to be the following: at the end of the star's life, during the red giant phase, the outer layers of the star are expelled by strong stellar winds. Eventually, after most of the red giant's atmosphere is dissipated, the exposed hot, luminous core emits ultraviolet radiation to ionize the ejected outer layers of the star. Absorbed ultraviolet light energizes the shell of nebulous gas around the central star, appearing as a bright colored planetary nebula at several discrete visible wavelengths. Planetary nebulae may play a crucial role in the chemical evolution of the Milky Way, returning material to the interstellar medium from stars where elements, the products of nucleosynthesis (such as carbon, nitrogen, oxygen and neon), have been created. Planetary nebulae are also observed in more distant galaxies, yielding useful information about their chemical abundances. In recent years, Hubble Space Telescope images have revealed many planetary nebulae to have extremely complex and varied morphologies. -
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). -
Arxiv:Astro-Ph/0305472 V1 23 May 2003
Astronomy & Astrophysics manuscript no. (will be inserted by hand later) An Hα survey aiming at the detection of extraplanar diffuse ionized gas in halos of edge–on spiral galaxies ? II. The Hα survey atlas and catalog J. Rossa ??1,2 and R.–J. Dettmar1 1 Astronomisches Institut, Ruhr–Universit¨at Bochum, D–44780 Bochum, Germany e-mail: [email protected], [email protected] 2 Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, U.S.A. (present address) Received 14 February 2003 / Accepted 6 May 2003 Abstract. In this second paper on the investigation of extraplanar diffuse ionized gas in nearby edge–on spiral galaxies we present the actual results of the individual galaxies of our Hα imaging survey. A grand total of 74 galaxies have been studied, including the 9 galaxies of a recently studied sub–sample (Rossa & Dettmar 2000). 40.5% of all studied galaxies reveal extraplanar diffuse ionized gas, whereas in 59.5% of the survey galaxies no extraplanar diffuse ionized gas could be detected. The average distances of this extended emission above the galactic midplane range from 1–2 kpc, while individual filaments in a few galaxies reach distances of up to |z| ∼ 6 kpc. In several cases a pervasive layer of ionized gas was detected, similar to the Reynolds layer in our Milky Way, while other galaxies reveal only extended emission locally. The morphology of the diffuse ionized gas is discussed for each galaxy and is compared with observations of other important ISM constituents in the context of the disk–halo connection, in those cases where published results were available. -
By SUSAN PATRICIA WORSWICK, B.Sc., A.R.C.S
ASTRONOMICAL ELECTRONOGRAPHIC PHOTOMETRY by SUSAN PATRICIA WORSWICK, B.Sc., A.R.C.S. March 1975 • A thesis submitted for the degree Astronomy Group of Doctor of Philosophy of the Physics Department University of London and for Imperial College the Diploma of Imperial College. London S.W.7. ii ABSTRACT An outline is given of the various systems that have been developed for the production and reduction of electronographic exposures. The typical limits to photometric accuracy are discussed. The performance of the individual constituents of a particular system consisting of a Spectracon image tube, nuclear emulsion and Joyce-Loebl MkIII CS microdensitometer is described. The problems of mounting the image tube on a telescope are discussed and are illustrated by a description of a camera design for the Cassegrain focus of the 60-inch reflector at Boyden Observatory. The computing procedures followed for the extraction of morphological and photometric data are given and are illustrated by some of the data produced so far. The need for monochromatic photometry of planetary nebulae is outlined and the suitability of electronography is shown by preliminary results from an ongoing observation programme. The problem of the removal of photocathode non-uniformities is tackled and the limitations set by this procedure are discussed together with the implications for astronomical photometry. Some improvements are proposed which might be made to existing systems and which should be considered in setting up new equipment. ACKNOWLEDGEMENTS I would like to express my thanks to Professor J. Ring for his supervision and his continued interest in this work. I am also grateful for the help extended by many members of the Astronomy Group, both past and present, in particular Dr C.I. -
MESSIER 15 RA(2000) : 21H 29M 58S DEC(2000): +12° 10'
MESSIER 15 RA(2000) : 21h 29m 58s DEC(2000): +12° 10’ 01” BASIC INFORMATION OBJECT TYPE: Globular Cluster CONSTELLATION: Pegasus BEST VIEW: Late October DISCOVERY: Jean-Dominique Maraldi, 1746 DISTANCE: 33,600 ly DIAMETER: 175 ly APPARENT MAGNITUDE: +6.2 APPARENT DIMENSIONS: 18’ FOV:Starry 1.00Night FOV: 60.00 Vulpecula Sagitta Pegasus NGC 7009 (THE SATURN NEBULA) Delphinus NGC 7009 RA(2000) : 21h 04m 10.8s DEC(2000): -11° 21’ 48.6” Equuleus Pisces Aquila NGC 7009 FOV: 5.00 Aquarius Telrad Capricornus Sagittarius Cetus Piscis Austrinus NGC 7009 Microscopium BASIC INFORMATION OBJECT TYPE: Planetary Nebula CONSTELLATION: Aquarius Sculptor BEST VIEW: Early November DISCOVERY: William Herschel, 1782 DISTANCE: 2000 - 4000 ly DIAMETER: 0.4 - 0.8 ly Grus APPARENT MAGNITUDE: +8.0 APPARENT DIMENSIONS: 41” x 35” Telescopium Telrad Indus NGC 7662 (THE BLUE SNOWBALL) RA(2000) : 23h 25m 53.6s DEC(2000): +42° 32’ 06” BASIC INFORMATION OBJECT TYPE: Planetary Nebula CONSTELLATION: Andromeda BEST VIEW: Late November DISCOVERY: William Herschel, 1784 DISTANCE: 1800 – 6400 ly DIAMETER: 0.3 – 1.1 ly APPARENT MAGNITUDE: +8.6 APPARENT DIMENSIONS: 37” MESSIER 52 RA(2000) : 23h 24m 48s DEC(2000): +61° 35’ 36” BASIC INFORMATION OBJECT TYPE: Open Cluster CONSTELLATION: Cassiopeia BEST VIEW: December DISCOVERY: Charles Messier, 1774 DISTANCE: ~5000 ly DIAMETER: 19 ly APPARENT MAGNITUDE: +7.3 APPARENT DIMENSIONS: 13’ AGE: 50 million years FOV:Starry 1.00Night FOV: 60.00 Auriga Cepheus Andromeda MESSIER 31 (THE ANDROMEDA GALAXY) M 31 RA(2000) : 00h 42m 44.3Cassiopeias DEC(2000): +41° 16’ 07.5” Perseus Lacerta AndromedaM 31 FOV: 5.00 Telrad Triangulum Taurus Orion Aries Andromeda M 31 Pegasus Pisces BASIC INFORMATION OBJECT TYPE: Galaxy CONSTELLATION: Andromeda Telrad BEST VIEW: December DISCOVERY: Abd al-Rahman al-Sufi, 964 Eridanus CetusDISTANCE: 2.5 million ly DIAMETER: ~250,000 ly* APPARENT MAGNITUDE: +3.4 APPARENT DIMENSIONS: 178’ x 63’ (3° x 1°) *This value represents the total diameter of the disk, based on multi-wavelength measurements. -
SAC's 110 Best of the NGC
SAC's 110 Best of the NGC by Paul Dickson Version: 1.4 | March 26, 1997 Copyright °c 1996, by Paul Dickson. All rights reserved If you purchased this book from Paul Dickson directly, please ignore this form. I already have most of this information. Why Should You Register This Book? Please register your copy of this book. I have done two book, SAC's 110 Best of the NGC and the Messier Logbook. In the works for late 1997 is a four volume set for the Herschel 400. q I am a beginner and I bought this book to get start with deep-sky observing. q I am an intermediate observer. I bought this book to observe these objects again. q I am an advance observer. I bought this book to add to my collect and/or re-observe these objects again. The book I'm registering is: q SAC's 110 Best of the NGC q Messier Logbook q I would like to purchase a copy of Herschel 400 book when it becomes available. Club Name: __________________________________________ Your Name: __________________________________________ Address: ____________________________________________ City: __________________ State: ____ Zip Code: _________ Mail this to: or E-mail it to: Paul Dickson 7714 N 36th Ave [email protected] Phoenix, AZ 85051-6401 After Observing the Messier Catalog, Try this Observing List: SAC's 110 Best of the NGC [email protected] http://www.seds.org/pub/info/newsletters/sacnews/html/sac.110.best.ngc.html SAC's 110 Best of the NGC is an observing list of some of the best objects after those in the Messier Catalog. -
OBSERVING GALAXIES in ANDROMEDA As You Look Towards
OBSERVING GALAXIES IN ANDROMEDA As you look towards Andromeda you are looking out into deep space underneath the Perseus spiral arm of our milky way. The constellation has a good density of observable galaxies. There is a group of relatively local galaxies which are less than 20 million light years away and then a big gap to the rest which are over 200 million light years away. The constellation is well place from late summer to mid-winter. M31 / M32 / M110 These galaxies are generally the first galaxies that amateur astronomers observe first. M31 is visible to the naked eye in dark skies. M31 whilst bright and large is fairly bland in appearance until you start to look a bit closer. With good conditions, the dark line of a dust lane is visible. I have to say that observing two of the globular clusters of this galaxy rank up there in my most memorable observations ever. M32 is very bright and I have seen it in binoculars as a very small bright blob. M110 can be a challenge to see with its low surface brightness. Having said that, I have seen it easily in my 80mm binoculars when the sky was transparent. NGC404 This galaxy is memorable to observe as it is close to the star Mirach and hence is known as Mirach’s ghost. It is a lovely circular low surface brightness glow that is visible with direct vision in my 10 inch reflector and was visible at low power with averted vision even with Mirach in the field of view. -
And – Objektauswahl NGC Teil 1
And – Objektauswahl NGC Teil 1 NGC 5 NGC 49 NGC 79 NGC 97 NGC 184 NGC 233 NGC 389 NGC 531 Teil 1 NGC 11 NGC 51 NGC 80 NGC 108 NGC 205 NGC 243 NGC 393 NGC 536 NGC 13 NGC 67 NGC 81 NGC 109 NGC 206 NGC 252 NGC 404 NGC 542 Teil 2 NGC 19 NGC 68 NGC 83 NGC 112 NGC 214 NGC 258 NGC 425 NGC 551 NGC 20 NGC 69 NGC 85 NGC 140 NGC 218 NGC 260 NGC 431 NGC 561 NGC 27 NGC 70 NGC 86 NGC 149 NGC 221 NGC 262 NGC 477 NGC 562 NGC 29 NGC 71 NGC 90 NGC 160 NGC 224 NGC 272 NGC 512 NGC 573 NGC 39 NGC 72 NGC 93 NGC 169 NGC 226 NGC 280 NGC 523 NGC 590 NGC 43 NGC 74 NGC 94 NGC 181 NGC 228 NGC 304 NGC 528 NGC 591 NGC 48 NGC 76 NGC 96 NGC 183 NGC 229 NGC 317 NGC 529 NGC 605 Sternbild- Zur Objektauswahl: Nummer anklicken Übersicht Zur Übersichtskarte: Objekt in Aufsuchkarte anklicken Zum Detailfoto: Objekt in Übersichtskarte anklicken And – Objektauswahl NGC Teil 2 NGC 620 NGC 709 NGC 759 NGC 891 NGC 923 NGC 1000 NGC 7440 NGC 7836 Teil 1 NGC 662 NGC 710 NGC 797 NGC 898 NGC 933 NGC 7445 NGC 668 NGC 712 NGC 801 NGC 906 NGC 937 NGC 7446 Teil 2 NGC 679 NGC 714 NGC 812 NGC 909 NGC 946 NGC 7449 NGC 687 NGC 717 NGC 818 NGC 910 NGC 956 NGC 7618 NGC 700 NGC 721 NGC 828 NGC 911 NGC 980 NGC 7640 NGC 703 NGC 732 NGC 834 NGC 912 NGC 982 NGC 7662 NGC 704 NGC 746 NGC 841 NGC 913 NGC 995 NGC 7686 NGC 705 NGC 752 NGC 845 NGC 914 NGC 996 NGC 7707 NGC 708 NGC 753 NGC 846 NGC 920 NGC 999 NGC 7831 Sternbild- Zur Objektauswahl: Nummer anklicken Übersicht Zur Übersichtskarte: Objekt in Aufsuchkarte anklicken Zum Detailfoto: Objekt in Übersichtskarte anklicken Auswahl And SternbildübersichtAnd -
Stories from Physics Astronomy And
King’s Research Portal Link to publication record in King's Research Portal Citation for published version (APA): Brock, R. (2021). Stories from Physics Booklet 7: Astronomy and Space. Institute of Physics. Citing this paper Please note that where the full-text provided on King's Research Portal is the Author Accepted Manuscript or Post-Print version this may differ from the final Published version. If citing, it is advised that you check and use the publisher's definitive version for pagination, volume/issue, and date of publication details. And where the final published version is provided on the Research Portal, if citing you are again advised to check the publisher's website for any subsequent corrections. General rights Copyright and moral rights for the publications made accessible in the Research Portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognize and abide by the legal requirements associated with these rights. •Users may download and print one copy of any publication from the Research Portal for the purpose of private study or research. •You may not further distribute the material or use it for any profit-making activity or commercial gain •You may freely distribute the URL identifying the publication in the Research Portal Take down policy If you believe that this document breaches copyright please contact [email protected] providing details, and we will remove access to the work immediately and investigate your claim. Download date: 01. Oct. 2021 IOP Education |Stories from physics booklet 7 Astronomy and space By Richard Brock iop.org Stories from physics Stories from physics Introduction Message from the author Perhaps of all the topics on the school physics curriculum, space most readily This is the seventh book in our series. -
SAA 100 Club
S.A.A. 100 Observing Club Raleigh Astronomy Club Version 1.2 07-AUG-2005 Introduction Welcome to the S.A.A. 100 Observing Club! This list started on the USENET newsgroup sci.astro.amateur when someone asked about everyone’s favorite, non-Messier objects for medium sized telescopes (8-12”). The members of the group nominated objects and voted for their favorites. The top 100 objects, by number of votes, were collected and ranked into a list that was published. This list is a good next step for someone who has observed all the objects on the Messier list. Since it includes objects in both the Northern and Southern Hemispheres (DEC +72 to -72), the award has two different levels to accommodate those observers who aren't able to travel. The first level, the Silver SAA 100 award requires 88 objects (all visible from North Carolina). The Gold SAA 100 Award requires all 100 objects to be observed. One further note, many of these objects are on other observing lists, especially Patrick Moore's Caldwell list. For convenience, there is a table mapping various SAA100 objects with their Caldwell counterparts. This will facilitate observers who are working or have worked on these lists of objects. We hope you enjoy looking at all the great objects recommended by other avid astronomers! Rules In order to earn the Silver certificate for the program, the applicant must meet the following qualifications: 1. Be a member in good standing of the Raleigh Astronomy Club. 2. Observe 80 Silver observations. 3. Record the time and date of each observation. -
Macrocosmo Nº33
HA MAIS DE DOIS ANOS DIFUNDINDO A ASTRONOMIA EM LÍNGUA PORTUGUESA K Y . v HE iniacroCOsmo.com SN 1808-0731 Ano III - Edição n° 33 - Agosto de 2006 * t i •■•'• bSÈlÈWW-'^Sif J fé . ’ ' w s » ws» ■ ' v> í- < • , -N V Í ’\ * ' "fc i 1 7 í l ! - 4 'T\ i V ■ }'- ■t i' ' % r ! ■ 7 ji; ■ 'Í t, ■ ,T $ -f . 3 j i A 'A ! : 1 l 4/ í o dia que o ceu explodiu! t \ Constelação de Andrômeda - Parte II Desnudando a princesa acorrentada £ Dicas Digitais: Softwares e afins, ATM, cursos online e publicações eletrônicas revista macroCOSMO .com Ano III - Edição n° 33 - Agosto de I2006 Editorial Além da órbita de Marte está o cinturão de asteróides, uma região povoada com Redação o material que restou da formação do Sistema Solar. Longe de serem chamados como simples pedras espaciais, os asteróides são objetos rochosos e/ou metálicos, [email protected] sem atmosfera, que estão em órbita do Sol, mas são pequenos demais para serem considerados como planetas. Até agora já foram descobertos mais de 70 Diretor Editor Chefe mil asteróides, a maior parte situados no cinturão de asteróides entre as órbitas Hemerson Brandão de Marte e Júpiter. [email protected] Além desse cinturão podemos encontrar pequenos grupos de asteróides isolados chamados de Troianos que compartilham a mesma órbita de Júpiter. Existem Editora Científica também aqueles que possuem órbitas livres, como é o caso de Hidalgo, Apolo e Walkiria Schulz Ícaro. [email protected] Quando um desses asteróides cruza a nossa órbita temos as crateras de impacto. A maior cratera visível de nosso planeta é a Meteor Crater, com cerca de 1 km de Diagramadores diâmetro e 600 metros de profundidade. -
Tracing the Local Volume Galaxy Halo-To-Stellar Mass Ratio with Satellite Kinematics
Received 10 July 2020; Revised 23 August 2020; Accepted 23 August 2020 DOI: xxx/xxxx 10.1002/asna.20210018 ORIGINAL ARTICLE Tracing the Local Volume galaxy halo-to-stellar mass ratio with satellite kinematics Igor Karachentsev | Olga Kashibadze Special Astrophysical Observatory, Russian Academy of Sciences, Russia Rapid advance has been made recently in accurate distance measurements for nearby Correspondence (D < 11 Mpc) galaxies based on the magnitude of the tip of red giant branch stars I. D. Karachentsev, SAO RAS, Nizhny Arkhyz, Karachay-Cherkessia, resolved with the Hubble Space Telescope. We use observational properties of galax- 369167 Russia. Email: [email protected] ies presented in the last version of Updated Nearby Galaxy Catalog to derive a halo mass of luminous galaxies via orbital motion of their companions. Our sample con- Funding Information tains 298 assumed satellites with known radial velocities around 25 Milky Way-like Russian Scientific Foundation, 19– massive galaxies and 65 assumed satellites around 47 fainter dominant galaxies. 02–00145. The average total mass-to-K-band luminosity ratio is 31 , 6M⊙_L⊙ for the lumi- nous galaxies, increasing up to ∼ 200M⊙_L⊙ toward dwarfs. The bulge-dominated luminous galaxies are characterized with êMT _LK ë = 73 , 15M⊙_L⊙, while the disc-dominated spirals have êMT _LK ë = 17:4 , 2:8M⊙_L⊙. We draw attention to a particular subsample of luminous spiral galaxies with signs of declining rotation curve, which have a radial velocity dispersion of satellites less than 55 km/s and a poor dark matter halo with êMT _LK ë = 5:5 , 1:1M⊙_L⊙.