Astronomie Mit Kleinem Budget Und Einfachen Mitteln
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1903Apj 18. .3415 the SPECTRUM of O CETL' by Joel Stebbins. On
.3415 18. 1903ApJ THE SPECTRUM OF o CETL' By Joel Stebbins. On account of the great instrumental power required for the observation of the spectra of faint objects, changes in the spectra of long-period variable stars have not been well studied. In fact, there is no star which undergoes a large variation in bright- ness whose spectrum has been systematically followed from maxi- mum to minimum, or vice versa. It is proposed to give here the results of a study of the spectrum of o Ceti> or Mira, made, at the suggestion of Director Campbell, with the thirty-six-inch refractor of the Lick Observatory, from June 1902 to January 1903. During this period the star faded in brightness from 3.8 to 9.0 magnitude. The first photograph of the spectrum was obtained about three weeks after the predicted time of maximum, and a series of plates was secured covering the interval to mini- mum. No negatives were obtained after the star had again begun to increase in brightness. The most important articles concerning the spectrum of Mira are those of Vogel,2 Sidgreaves,3 and Campbell.4 Neither Vogel nor Sidgreaves followed the star long enough to find much change in its spectrum, and Campbell’s work was mainly in con- nection with observations of the star for radial velocity, with the Mills spectrograph. INSTRUMENTS AND METHODS. The spectrograph used in my observations was the one employed rby Messrs. Campbell and Wright in their work on 1 “ Dissertation in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in the University of California,” Lick Observatory Bulletin No. -
April 14 2018 7:00Pm at the April 2018 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 President’s Message Tim Frazier Saturday, April 14th 2018 April 2018 7:00pm at the Herrett Center for Arts & Science College of Southern Idaho. It really is beginning to feel like spring. The weather is more moderate and there will be, hopefully, clearer skies. (I write this with some trepidation as I don’t want to jinx Public Star Party Follows at the it in a manner similar to buying new equipment will ensure at least two weeks of Centennial Observatory cloudy weather.) Along with the season comes some great spring viewing. Leo is high overhead in the early evening with its compliment of galaxies as is Coma Club Officers Berenices and Virgo with that dense cluster of extragalactic objects. Tim Frazier, President One of my first forays into the Coma-Virgo cluster was in the early 1960’s with my [email protected] new 4 ¼ inch f/10 reflector and my first star chart, the epoch 1960 version of Norton’s Star Atlas. I figured from the maps I couldn’t miss seeing something since Robert Mayer, Vice President there were so many so closely packed. That became the real problem as they all [email protected] appeared as fuzzy spots and the maps were not detailed enough to distinguish one galaxy from another. I still have that atlas as it was a precious Christmas gift from Gary Leavitt, Secretary my grandparents but now I use better maps, larger scopes and GOTO to make sure [email protected] it is M84 or M86. -
A Terrestrial Planet Candidate in a Temperate Orbit Around Proxima Centauri
A terrestrial planet candidate in a temperate orbit around Proxima Centauri Guillem Anglada-Escude´1∗, Pedro J. Amado2, John Barnes3, Zaira M. Berdinas˜ 2, R. Paul Butler4, Gavin A. L. Coleman1, Ignacio de la Cueva5, Stefan Dreizler6, Michael Endl7, Benjamin Giesers6, Sandra V. Jeffers6, James S. Jenkins8, Hugh R. A. Jones9, Marcin Kiraga10, Martin Kurster¨ 11, Mar´ıa J. Lopez-Gonz´ alez´ 2, Christopher J. Marvin6, Nicolas´ Morales2, Julien Morin12, Richard P. Nelson1, Jose´ L. Ortiz2, Aviv Ofir13, Sijme-Jan Paardekooper1, Ansgar Reiners6, Eloy Rodr´ıguez2, Cristina Rodr´ıguez-Lopez´ 2, Luis F. Sarmiento6, John P. Strachan1, Yiannis Tsapras14, Mikko Tuomi9, Mathias Zechmeister6. July 13, 2016 1School of Physics and Astronomy, Queen Mary University of London, 327 Mile End Road, London E1 4NS, UK 2Instituto de Astrofsica de Andaluca - CSIC, Glorieta de la Astronoma S/N, E-18008 Granada, Spain 3Department of Physical Sciences, Open University, Walton Hall, Milton Keynes MK7 6AA, UK 4Carnegie Institution of Washington, Department of Terrestrial Magnetism 5241 Broad Branch Rd. NW, Washington, DC 20015, USA 5Astroimagen, Ibiza, Spain 6Institut fur¨ Astrophysik, Georg-August-Universitat¨ Gottingen¨ Friedrich-Hund-Platz 1, 37077 Gottingen,¨ Germany 7The University of Texas at Austin and Department of Astronomy and McDonald Observatory 2515 Speedway, C1400, Austin, TX 78712, USA 8Departamento de Astronoma, Universidad de Chile Camino El Observatorio 1515, Las Condes, Santiago, Chile 9Centre for Astrophysics Research, Science & Technology Research Institute, University of Hert- fordshire, Hatfield AL10 9AB, UK 10Warsaw University Observatory, Aleje Ujazdowskie 4, Warszawa, Poland 11Max-Planck-Institut fur¨ Astronomie Konigstuhl¨ 17, 69117 Heidelberg, Germany 12Laboratoire Univers et Particules de Montpellier, Universit de Montpellier, Pl. -
Pulsating Low-Mass White Dwarfs in the Frame of New Evolutionary Sequences I
A&A 569, A106 (2014) Astronomy DOI: 10.1051/0004-6361/201424352 & c ESO 2014 Astrophysics Pulsating low-mass white dwarfs in the frame of new evolutionary sequences I. Adiabatic properties A. H. Córsico1,2 andL.G.Althaus1,2 1 Grupo de Evolución Estelar y Pulsaciones. Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata, Paseo del Bosque s/n, 1900 La Plata, Argentina 2 IALP – CONICET, Argentina e-mail: acorsico,[email protected] Received 6 June 2014 / Accepted 31 July 2014 ABSTRACT Context. Many low-mass white dwarfs with masses M∗/ M ∼< 0.45, including the so-called extremely low-mass white dwarfs (M∗/ M ∼< 0.20−0.25), have recently been discovered in the field of our Galaxy through dedicated photometric surveys. The sub- sequent discovery of pulsations in some of them has opened the unprecedented opportunity of probing the internal structure of these ancient stars. Aims. We present a detailed adiabatic pulsational study of these stars based on full evolutionary sequences derived from binary star evolution computations. The main aim of this study is to provide a detailed theoretical basis of reference for interpreting present and future observations of variable low-mass white dwarfs. Methods. Our pulsational analysis is based on a new set of He-core white-dwarf models with masses ranging from 0.1554 to 0.4352 M derived by computing the non-conservative evolution of a binary system consisting of an initially 1 M ZAMS star and a 1.4 M neutron star. We computed adiabatic radial ( = 0) and non-radial ( = 1, 2) p and g modes to assess the dependence of the pulsational properties of these objects on stellar parameters such as the stellar mass and the effective temperature, as well as the effects of element diffusion. -
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. -
January/February 1992
42 29'20.3° Detroit N Latitude Southfield Rec. Cen. Astronomical :c ro '-' O o 3 • Lal• er f2 Society <.: a. ...... Newsletter «0 JANUARY/FEBRUARY/1992 FROM THE PRESIDENT Well, as the year starts, we have some great lectures lined up for January and February. If you received a telescope recently or during Christmas and/or thinking of buying one, the January · lecture will be an interesting lecture for. you! We will also have various types of telescopes on display that you can ask questions about. February brings us another interesting lecture by Professor Kauppila from Wayne State University. Professor Kauppila is a noted authority in the area of antimatter research and gamma ray astronomy. The lecture will be designed for the general audience but if you want to ask a technical question during the question and answer period, feel free to do so! The thumb area astronomers are hosting another observing session tentatively scheduled for February 8, 1992 - more details will be announced at meetings and Skywatchers Hotline (837-0130). We will continue to hold some observing sessions at Camp Dearborn but on a limited basis. Clear Skies! Jack Brisbin 455-7827 SCHEDULE OF EVENTS January 3, Friday Board of Directors meeting, 7:00 pm. Elections • workshop activities, 8:15 pm. January 17, Friday 8:15 pm; General meeting and lecture: A Telescope, choosing and buying, by Pat Lowery, an instructor at the Highland Park Community College. If you are thinking of buying a telescope or you have already bought a telescope. This lecture is designed for the general public. -
Basics of Astrophysics Revisited. I. Mass- Luminosity Relation for K, M and G Class Stars
Basics of astrophysics revisited. I. Mass- luminosity relation for K, M and G class stars Edgars Alksnis [email protected] Small volume statistics show, that luminosity of slow rotating stars is proportional to their angular momentums of rotation. Cause should be outside of standard solar model. Slow rotating giants and dim dwarfs are not out of „main sequence” in this concept. Predictive power of stellar mass-radius- equatorial rotation speed-luminosity relation has been offered to test in numerous examples. Keywords: mass-luminosity relation, stellar rotation, stellar mass prediction, stellar rotation prediction ...Such vibrations would proceed from deep inside the sun. They are a fast way of transporting large amounts of energy from the interior to the surface that is not envisioned in present theory.... They could stir up the material inside the sun, which current theory tends to see as well layered, and that could affect the fusion dynamics. If they come to be generally accepted, they will require a reworking of solar theory, and that carries in its train a reworking of stellar theory generally. These vibrations could reverberate throughout astronomy. (Science News, Vol. 115, April 21, 1979, p. 270). Actual expression for stellar mass-luminosity relation (fig.1) Fig.1 Stellar mass- luminosity relation. Credit: Ay20. L- luminosity, relative to the Sun, M- mass, relative to the Sun. remain empiric and in fact contain unresolvable contradiction: stellar luminosity basically is connected with their surface area (radius squared) but mass (radius in cube) appears as a factor which generate luminosity. That purely geometric difference had pressed astrophysicists to place several classes of stars outside of „main sequence” in the frame of their strange theoretic constructions. -
Mercury Society
Cotswold C A Astronomical S Mercury Society Volume 19 Issue 5 - January 2004 Inside this issue . Editor’s Spot 2 Coordinator’s Spot 2 The Young Challengers 4 Astronauts and Cosmonauts 5 Accommodation Review 7 Redshift 5 - a review 8 Deep Impact certificate 9 Making Astronomy (part 2) 10 Occultation (that nearly was) 13 Holiday Greetings 14 Derek Maskell’s telescope Mercury - The Newsletter of the Cotswold Astronomical Society, founded 1982 Editor’s Spot are dealing with here on Earth are just as per- by Peter Cadogan tinent as they were then, and indeed the world is a very dangerous place, perhaps for many of All is looking very bleak for Beagle 2, so let’s us more so. Today’s bomb was in Moscow, not now hope that the rest of Mars Express goes far from where I visited the Kremlin and well and trust that this will not mark the end reported to you in a past Mercury, and of this country’s adventures into space. It was although the prospect of visiting many places a joy to be in Pembrokeshire over the New today seems to put many of them off limits, it Year. Not only did I participate in the charity should not deter us. swim in the sea, I was also able to see all three open clusters in Auriga with the naked eye, In these times many people say that space surprising when they are supposedly below exploration is a waste of money and problems magnitude 6. Oh for such dark skies at home. -
Physical Properties of the Current Census of Northern White Dwarfs
PHYSICAL PROPERTIES OF THE CURRENT CENSUS OF NORTHERN WHITE DWARFS WITHIN 40 pc OF THE SUN M.-M. Limoges,1,3 P. Bergeron,1 and S. L´epine2,4 1D´epartement de Physique, Universit´ede Montr´eal, C.P. 6128, Succ. Centre-Ville, Montr´eal, Qu´ebec H3C 3J7, Canada 2Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30302-4106 [email protected], [email protected], [email protected] ABSTRACT We present a detailed description of the physical properties of our current census of white dwarfs within 40 pc of the Sun, based on an exhaustive spectro- scopic survey of northern hemisphere candidates from the SUPERBLINK proper motion database. Our method for selecting white dwarf candidates is based on a combination of theoretical color-magnitude relations and reduced proper motion diagrams. We reported in an earlier publication the discovery of nearly 200 new white dwarfs, and we present here the discovery of an additional 133 new white dwarfs, among which we identify 96 DA, 3 DB, 24 DC, 3 DQ, and 7 DZ stars. We further identify 178 white dwarfs that lie within 40 pc of the Sun, represent- ing a 40% increase of the current census, which now includes 492 objects. We estimate the completeness of our survey at between 66 and 78%, allowing for uncertainties in the distance estimates. We also perform a homogeneous model atmosphere analysis of this 40 pc sample and find a large fraction of massive white dwarfs, indicating that we are successfully recovering the more massive, and less luminous objects often missed in other surveys. -
Observer's Handbook 1988
OBSERVER’S HANDBOOK 1988 EDITOR: ROY L. BISHOP THE ROYAL ASTRONOMICAL SOCIETY OF CANADA CONTRIBUTORS AND ADVISORS A l a n H. B a t t e n , Dominion Astrophysical Observatory, 5071 W. Saanich Road, Victoria, BC, Canada V8X 4M6 (The Nearest Stars). L a r r y D. B o g a n , Department of Physics, Acadia University, Wolfville, NS, Canada B0P 1X0 (Configurations of Saturn’s Satellites). T e r e n c e D ic k i n s o n , Yarker, ON, Canada K0K 3N0 (The Planets). D a v id W. D u n h a m , International Occultation Timing Association, P.O. Box 7488, Silver Spring, MD 20907, U.S.A. (Lunar and Planetary Occultations). A l a n D y e r , Edmonton Space Sciences Centre, 11211-142 St., Edmonton, AB, Canada T5M 4A1 (Messier Catalogue, Deep-Sky Objects). F r e d E s p e n a k , Planetary Systems Branch, NASA-Goddard Space Flight Centre, Greenbelt, MD, U.S.A. 20771 (Eclipses and Transits). M a r ie F id l e r , 23 Lyndale D r., Willowdale, ON, Canada M2N 2X9 (Observatories and Planetaria). V ic t o r G a i z a u s k a s , C h r is t ie D o n a l d s o n , T e d K e n n e l l y , Herzberg Institute of Astrophysics, National Research Council, Ottawa, ON, Canada K1A 0R6 (Solar Activity). R o b e r t F. G a r r is o n , David Dunlap Observatory, University of Toronto, Box 360, Richmond Hill, ON, Canada L4C 4Y6 (The Brightest Stars). -
NCRAL Northern Lights Spring 2021
to continue serving as Northern Lights newsletter editor if the INSIDE THIS ISSUE OF Northern Lights new Regional Chair deems that desirable. The Region needs individuals willing to stand for election NCRAL Chair’s Message…..............................……………………1 to the following positions for our May election: Chair and Vice NCRAL Elections Online May 7-8, 2021…………………………….2 Chair. The terms of the current office holders – yours truly Basic NCRAL Officer Job Responsibilities…..…………….……….3 and Bill Davidson, expire on May 8th. Our present Secretary- NCRAL Financial Statement Winter 2021……..…………….……4 Treasurer, Roy Gustafson, is willing to stand for election to Pike River Starfest……………………..…………………….……..………4 complete the term to which he was appointed last spring after Call for 2021 NCRAL Nominations & Applications……….......5 NCRAL 2020 was postponed. Others may stand for election to NCRAL Seasonal Messier Marathon Awards…………….………7 this office too if they are desirous of completing the one-year Noteworthy!……………………………………………………………………7 unexpired term of the current office holder. Bill Davidson, our A Homebuilt Solar Wind Magnetometer………………..………..7 Regional Representative to the Astronomical League, Venus: Evening Star 2021 by Jeffrey L. Hunt………………..….10 continues in this position unless he should become Chair. Astronomical League 75th Anniversary Coming……..…….…18 This year’s elections will be conducted electronically with Future NCRAL Conventions…………………………………..…….….19 special electors. I sent out an email notice on February 22nd Seasonal Messier Mini Marathon Observing Program……19 about the election procedures to be followed in the event of Add Your Email Address to NCRAL Member Database…...20 not holding an annual business meeting. (That email is NCRAL Website………………………………………………………….….20 repeated starting on page 2 of this newsletter.) Procedures Regional Officer & Leader Contact Information………..……21 are stipulated by the Region’s Bylaws. -
Fy05 Accomplishments and Fy06 Plans Helmut A. Abt
Appendix A NOAO SCIENTIFIC STAFF: FY05 ACCOMPLISHMENTS AND FY06 PLANS ¬New appointment in FY05 S Non-NSF (external) funding ±Term ended in FY05 HELMUT A. ABT, Emeritus Astronomer Research Interests Evolutionary stellar problems, stellar characteristics, publication studies FY05 Accomplishments Abt and C. Boonyarak (U. Thailand) studied rotation velocities of stars in binaries. It was known that those with periods shorter than several days all have synchronized rotational and orbital motions. They found that binaries with periods up to 500 days have reduced rotational velocities due to tidal interactions. Abt found that the eccentricities in binaries vary from zero in close binaries to an average of 0.5 in binaries with periods greater than 1000 days. In the initial formation of binaries, all eccentricities are equally probable. FY06 Plans Abt is trying to understand the hot inner disks that occur around, at any one time, one-quarter of the rapidly- rotating A dwarfs. These disks have no connection with the outer cool dust disks found around many stars like Vega and beta Pictoris. These disks come and go on time scales of decades. Such stars do not occur in the low-density Local Interstellar Bubble, so they are material accreted from the interstellar medium. Theoretical aspects of the physical processes is being done with M. Marlborough (U. Western Ontario). TAFT E. ARMANDROFF, Astronomer (Director, NOAO Gemini Science Center) Research Interests Stellar populations in the Galaxy and nearby galaxies; dwarf spheroidal galaxies; globular clusters FY05 Accomplishments Armandroff has been studying the dwarf spheroidal satellite galaxies of M31 in collaboration with Da Costa (RSAA/ANU), Pritzl (Macalester), and Jacoby (WIYN).