Unknown Amorphous Carbon II. LRS SPECTRA the Sample Consists Of
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JOHN R. THORSTENSEN Address
CURRICULUM VITAE: JOHN R. THORSTENSEN Address: Department of Physics and Astronomy Dartmouth College 6127 Wilder Laboratory Hanover, NH 03755-3528; (603)-646-2869 [email protected] Undergraduate Studies: Haverford College, B. A. 1974 Astronomy and Physics double major, High Honors in both. Graduate Studies: Ph. D., 1980, University of California, Berkeley Astronomy Department Dissertation : \Optical Studies of Faint Blue X-ray Stars" Graduate Advisor: Professor C. Stuart Bowyer Employment History: Department of Physics and Astronomy, Dartmouth College: { Professor, July 1991 { present { Associate Professor, July 1986 { July 1991 { Assistant Professor, September 1980 { June 1986 Research Assistant, Space Sciences Lab., U.C. Berkeley, 1975 { 1980. Summer Student, National Radio Astronomy Observatory, 1974. Summer Student, Bartol Research Foundation, 1973. Consultant, IBM Corporation, 1973. (STARMAP program). Honors and Awards: Phi Beta Kappa, 1974. National Science Foundation Graduate Fellow, 1974 { 1977. Dorothea Klumpke Roberts Award of the Berkeley Astronomy Dept., 1978. Professional Societies: American Astronomical Society Astronomical Society of the Pacific International Astronomical Union Lifetime Publication List * \Can Collapsed Stars Close the Universe?" Thorstensen, J. R., and Partridge, R. B. 1975, Ap. J., 200, 527. \Optical Identification of Nova Scuti 1975." Raff, M. I., and Thorstensen, J. 1975, P. A. S. P., 87, 593. \Photometry of Slow X-ray Pulsars II: The 13.9 Minute Period of X Persei." Margon, B., Thorstensen, J., Bowyer, S., Mason, K. O., White, N. E., Sanford, P. W., Parkes, G., Stone, R. P. S., and Bailey, J. 1977, Ap. J., 218, 504. \A Spectrophotometric Survey of the A 0535+26 Field." Margon, B., Thorstensen, J., Nelson, J., Chanan, G., and Bowyer, S. -
The Orbital Ephemeris of the Classical Nova RR Pictoris: Presence of A
Draft version August 5, 2018 Preprint typeset using LATEX style AASTeX6 v. 1.0 THE ORBITAL EPHEMERIS OF THE CLASSICAL NOVA RR PICTORIS: PRESENCE OF A THIRD BODY? N. Vogt1, M. R. Schreiber1, F.-J. Hambsch3,4, G. Retamales1, C. Tappert1, L. Schmidtobreick2 & I. Fuentes-Morales1 1Instituto de F´ısica y Astronom´ıa, Universidad de Valpara´ıso, Valpara´ıso, Chile 2European Southern Observatory, Santiago 19, Chile, Casilla 1900 3Vereniging Voor Sterrenkunde (VVS), Oude Bleken 12, 2400 Mol, Belgium 4 American Association of Variable Star Observers, 49 Bay State Rd., Cambridge, MA02138, USA ABSTRACT The ex-nova RR Pic presents a periodic hump in its light curve which is considered to refer to its orbital period. Analyzing all available epochs of these hump maxima in the literature, and combining them with those from new light curves obtained in 2013 and 2014, we establish an unique cycle count scheme valid during the past 50 years, and derive an ephemeris with the orbital period 0.145025959(15) days. The O - C diagram of this linear ephemeris reveals systematic deviations which could have different causes. One of them could be a light-travel-time effect caused by the presence of a hypothetical third body near the star/brown dwarf mass limit, with an orbital period of the order of 70 years. We also examine the difficulty of the problematic of detecting sub-stellar or planetary companions of close red- dwarf white-dwarf binaries (including cataclysmic variables), and discuss other possible mechanisms responsible for the observed deviations in O - C. For RR Pic, we propose strategies in order to solve this question by new observations. -
September 2020 BRAS Newsletter
A Neowise Comet 2020, photo by Ralf Rohner of Skypointer Photography Monthly Meeting September 14th 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: NASA Michoud Assembly Facility Director, Robert Champion What's In This Issue? President’s Message Secretary's Summary Business Meeting Minutes Outreach Report Asteroid and Comet News Light Pollution Committee Report Globe at Night Member’s Corner –My Quest For A Dark Place, by Chris Carlton Astro-Photos by BRAS Members Messages from the HRPO REMOTE DISCUSSION Solar Viewing Plus Night Mercurian Elongation Spooky Sensation Great Martian Opposition Observing Notes: Aquila – The Eagle Like this newsletter? See PAST ISSUES online back to 2009 Visit us on Facebook – Baton Rouge Astronomical Society Baton Rouge Astronomical Society Newsletter, Night Visions Page 2 of 27 September 2020 President’s Message Welcome to September. You may have noticed that this newsletter is showing up a little bit later than usual, and it’s for good reason: release of the newsletter will now happen after the monthly business meeting so that we can have a chance to keep everybody up to date on the latest information. Sometimes, this will mean the newsletter shows up a couple of days late. But, the upshot is that you’ll now be able to see what we discussed at the recent business meeting and have time to digest it before our general meeting in case you want to give some feedback. Now that we’re on the new format, business meetings (and the oft neglected Light Pollution Committee Meeting), are going to start being open to all members of the club again by simply joining up in the respective chat rooms the Wednesday before the first Monday of the month—which I encourage people to do, especially if you have some ideas you want to see the club put into action. -
The Planets for 1955 24 Eclipses, 1955 ------29 the Sky and Astronomical Phenomena Month by Month - - 30 Phenomena of Jupiter’S S a Te Llite S
THE OBSERVER’S HANDBOOK FOR 1955 PUBLISHED BY The Royal Astronomical Society of Canada C. A. C H A N T, E d ito r RUTH J. NORTHCOTT, A s s is t a n t E d ito r DAVID DUNLAP OBSERVATORY FORTY-SEVENTH YEAR OF PUBLICATION P r i c e 50 C e n t s TORONTO 13 Ross S t r e e t Printed for th e Society By the University of Toronto Press THE ROYAL ASTRONOMICAL SOCIETY OF CANADA The Society was incorporated in 1890 as The Astronomical and Physical Society of Toronto, assuming its present name in 1903. For many years the Toronto organization existed alone, but now the Society is national in extent, having active Centres in Montreal and Quebec, P.Q.; Ottawa, Toronto, Hamilton, London, and Windsor, Ontario; Winnipeg, Man.; Saskatoon, Sask.; Edmonton, Alta.; Vancouver and Victoria, B.C. As well as nearly 1000 members of these Canadian Centres, there are nearly 400 members not attached to any Centre, mostly resident in other nations, while some 200 additional institutions or persons are on the regular mailing list of our publications. The Society publishes a bi-monthly J o u r n a l and a yearly O b s e r v e r ’s H a n d b o o k . Single copies of the J o u r n a l are 50 cents, and of the H a n d b o o k , 50 cents. Membership is open to anyone interested in astronomy. Annual dues, $3.00; life membership, $40.00. -
Ludwig Neidhart
© Dr. Ludwig Neidhart, 1998, 2007 „Als die Zeit erfüllt war ...“ Ein Diskussionsbeitrag zu Grundproblemen der biblischen Weihnachtgeschichte und der Datierung der Geburt Christi von Ludwig Neidhart (überarbeitete Version, Stand 07.04.2019) Erstmals erschienen in: Brücke zum Menschen Nr. 133, 1. Quartal 1998 Leicht überarbeitete Version in: Pro Sancta Ecclesia Nr. 21, 2007, S. 20–110 Auszug mit dem Titel ‚Die Magier und der Stern’ in: Dörthe Emig-Herchen (Hg.), Silberglanz in stillen Gassen. Weihnachts-Anthologie 2007, Frankfurt a.M., 2007, S. 221–246 Inhaltsverzeichnis 1. Wie kam man auf den 25. Dezember?...................................................................................................2 2. Wie alt ist das Geburtsfest Christi am 25. Dezember?........................................................................3 3. Frühchristliche Traditionen über den Geburtstag Jesu......................................................................4 4. Kann Christus im Dezember geboren sein?.........................................................................................7 5. Biblische Chronologie des Lebens Christi............................................................................................8 5.1. Die Dauer des öffentlichen Wirkens Jesu......................................................................................8 5.2. Jesus starb am 7. April des Jahres 30.............................................................................................9 5.3. Exkurs über die Stunde der Kreuzigung.....................................................................................13 -
A Review of the Disc Instability Model for Dwarf Novae, Soft X-Ray Transients and Related Objects a J.M
A review of the disc instability model for dwarf novae, soft X-ray transients and related objects a J.M. Hameury aObservatoire Astronomique de Strasbourg ARTICLEINFO ABSTRACT Keywords: I review the basics of the disc instability model (DIM) for dwarf novae and soft-X-ray transients Cataclysmic variable and its most recent developments, as well as the current limitations of the model, focusing on the Accretion discs dwarf nova case. Although the DIM uses the Shakura-Sunyaev prescription for angular momentum X-ray binaries transport, which we know now to be at best inaccurate, it is surprisingly efficient in reproducing the outbursts of dwarf novae and soft X-ray transients, provided that some ingredients, such as irradiation of the accretion disc and of the donor star, mass transfer variations, truncation of the inner disc, etc., are added to the basic model. As recently realized, taking into account the existence of winds and outflows and of the torque they exert on the accretion disc may significantly impact the model. I also discuss the origin of the superoutbursts that are probably due to a combination of variations of the mass transfer rate and of a tidal instability. I finally mention a number of unsolved problems and caveats, among which the most embarrassing one is the modelling of the low state. Despite significant progresses in the past few years both on our understanding of angular momentum transport, the DIM is still needed for understanding transient systems. 1. Introduction tems using Doppler tomography techniques (Steeghs et al. 1997; Marsh and Horne 1988; see also Marsh and Schwope Dwarf novae (DNe) are cataclysmic variables (CV) that 2016 for a recent review). -
Stars and Their Spectra: an Introduction to the Spectral Sequence Second Edition James B
Cambridge University Press 978-0-521-89954-3 - Stars and Their Spectra: An Introduction to the Spectral Sequence Second Edition James B. Kaler Index More information Star index Stars are arranged by the Latin genitive of their constellation of residence, with other star names interspersed alphabetically. Within a constellation, Bayer Greek letters are given first, followed by Roman letters, Flamsteed numbers, variable stars arranged in traditional order (see Section 1.11), and then other names that take on genitive form. Stellar spectra are indicated by an asterisk. The best-known proper names have priority over their Greek-letter names. Spectra of the Sun and of nebulae are included as well. Abell 21 nucleus, see a Aurigae, see Capella Abell 78 nucleus, 327* ε Aurigae, 178, 186 Achernar, 9, 243, 264, 274 z Aurigae, 177, 186 Acrux, see Alpha Crucis Z Aurigae, 186, 269* Adhara, see Epsilon Canis Majoris AB Aurigae, 255 Albireo, 26 Alcor, 26, 177, 241, 243, 272* Barnard’s Star, 129–130, 131 Aldebaran, 9, 27, 80*, 163, 165 Betelgeuse, 2, 9, 16, 18, 20, 73, 74*, 79, Algol, 20, 26, 176–177, 271*, 333, 366 80*, 88, 104–105, 106*, 110*, 113, Altair, 9, 236, 241, 250 115, 118, 122, 187, 216, 264 a Andromedae, 273, 273* image of, 114 b Andromedae, 164 BDþ284211, 285* g Andromedae, 26 Bl 253* u Andromedae A, 218* a Boo¨tis, see Arcturus u Andromedae B, 109* g Boo¨tis, 243 Z Andromedae, 337 Z Boo¨tis, 185 Antares, 10, 73, 104–105, 113, 115, 118, l Boo¨tis, 254, 280, 314 122, 174* s Boo¨tis, 218* 53 Aquarii A, 195 53 Aquarii B, 195 T Camelopardalis, -
Present Status and Future Directions of the EVN
http://www.evlbi.org/ Present status and future directions of the EVN Michael Lindqvist, Onsala Space Observatory Zsolt Paragi, JIVE Onsala Space Observatory http://www.evlbi.org/ Thanks Tasso! Onsala Space Observatory http://www.evlbi.org/ VLBI science • Radio jet & black hole physics • Radio source evolution • Astrometry • Galactic and extra-galactic masers • Gravitational lenses • Supernovae and gamma-ray-burst studies • Nearby and distant starburst galaxies • Nature of faint radio source population • HI absorption studies in AGN • Space science VLBI • Transients • SETI Onsala Space Observatory http://www.evlbi.org/ Description of the EVN • The European VLBI Network (EVN) was formed in 1980. Today it includes 15 major institutes, including the Joint Institute for VLBI ERIC, JIVE • JIVE operates EVN correlator. JIVE is also involved in supporting EVN users and operations of EVN as a facility. JIVE has officially been established as an European Research Infrastructure Consortium (ERIC). • The EVN operates an “open sky” policy • No standing centralised budget for the EVN - distributed European facility Onsala Space Observatory http://www.evlbi.org/ The network Onsala Space Observatory http://www.evlbi.org/ EVN and e-VLBI From tape reel to intercontinental light paths • Pieces falling into place around 2003: – Introduction of Mark5 recording system (game changer) by Haystack Observatory – Emergence of high bandwidth optical fibre networks e-VLBI JIVE Hot scienceJIVE • The development of e-VLBI has been spearheaded by the JIVE/EVN (EXPReS, Garrett) • In this way, the EVN/JIVE is a recognized SKA pathfinder Onsala Space Observatory http://www.evlbi.org/ e-VLBI - rapid turn-around • e-VLBI has made rapid turn-around possible – X-ray, γ-ray binaries in flaring states (including novae) – AGN γ-ray outbursts — locus of VHE emission – Other high-energy flaring (e.g., Crab) – Outbursts in Mira variables (spectral-line) – Just-exploded GRBs, SNe – Binaries (incl. -
Shells Around Southern Novae H
No. 17 - June 1979 Shells Around Southern Novae H. W. Duerbeck and W. C. Seitter Spencer Jones published in 1931 a bulky volume of Although less spectacular than their big brothers, spectroscopic and visual observations made at the Cape the supernovae, the novae are by no means less Observatory. Another southern observer, J. Hartmann in interesting. They are also much more frequent Buenos Aires, observed the nova spectroscopically and wrote the most concise astronomical paper ever publish and several are known in the southern sky. After ed, a telegram senJ to the Astronomische Nachrichten: the initial explosion, a shell expands around the "Nova problem solved; star blows up, bursts." And indeed, nova and may become visible after a while. Drs. when double-star observers examined the postnova two Hilmar Duerbeck and Waltraut Seitter from the Hoher-List Observatory, near Bonn, FRG, recently observed three southern novae. The excellent resolution of the 3.6 m photos makes itpossible to see details in the very faint nova shells that have never been perceived before. The southern sky comprises one of the most fanciful supernova remnants-the extended spider web of the Gum nebula. It harbours also some less spectacular, tiny, astronomically shortlived phenomena: the remnants of near nova explosions. They can be observed for only a few decades after outburst, before they thin out and merge into the interstellar medium. Due to their small size and low surface brightness, they require large telescopes, such as have recently become available in the southern hemi sphere. Fortunately, some observing time was granted to us before the above-mentioned disappearances! RR Pictoris Two brilliant novae shone in the southern sky in this century. -
Publications of the Astronomical Society of the Pacific Vol. 106 1994 March No. 697 Publications of the Astronomical Society Of
Publications of the Astronomical Society of the Pacific Vol. 106 1994 March No. 697 Publications of the Astronomical Society of the Pacific 106: 209-238, 1994 March Invited Review Paper The DQ Herculis Stars Joseph Patterson Department of Astronomy, Columbia University, 538 West 120th Street, New York, New York 10027 Electronic mail: [email protected] Received 1993 September 2; accepted 1993 December 9 ABSTRACT. We review the properties of the DQ Herculis stars: cataclysmic variables containing an accreting, magnetic, rapidly rotating white dwarf. These stars are characterized by strong X-ray emission, high-excitation spectra, and very stable optical and X-ray pulsations in their light curves. There is considerable resemblance to their more famous cousins, the AM Herculis stars, but the latter class is additionally characterized by spin-orbit synchronism and the presence of strong circular polarization. We list eighteen stars passing muster as certain or very likely DQ Her stars. The rotational periods range from 33 s to 2.0 hr. Additional periods can result when the rotating searchlight illuminates other structures in the binary. A single hypothesis explains most of the observed properties: magnetically channeled accretion within a truncated disk. Some accretion flow still seems to proceed directly to the magnetosphere, however. The white dwarfs' magnetic moments are in the range 1032-1034 G cm3, slightly weaker than in AM Her stars but with some probable overlap. The more important reason why DQ Hers have broken synchronism is probably their greater accretion rate and orbital separation. The observed Lx/L v values are surprisingly low for a radially accreting white dwarf, suggesting that most of the accretion energy is not radiated in a strong shock above the magnetic pole. -
Cataclysmic Variables
Cataclysmic variables Article (Accepted Version) Smith, Robert Connon (2006) Cataclysmic variables. Contemporary Physics, 47 (6). pp. 363-386. ISSN 0010-7514 This version is available from Sussex Research Online: http://sro.sussex.ac.uk/id/eprint/2256/ This document is made available in accordance with publisher policies and may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher’s version. Please see the URL above for details on accessing the published version. Copyright and reuse: Sussex Research Online is a digital repository of the research output of the University. Copyright and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable, the material made available in SRO has been checked for eligibility before being made available. Copies of full text items generally can be reproduced, displayed or performed and given to third parties in any format or medium for personal research or study, educational, or not-for-profit purposes without prior permission or charge, provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. http://sro.sussex.ac.uk Cataclysmic variables Robert Connon Smith Department of Physics and Astronomy, University of Sussex, Falmer, Brighton BN1 9QH, UK E-mail: [email protected] Abstract. Cataclysmic variables are binary stars in which a relatively normal star is transferring mass to its compact companion. -
An Old Nova Showing Superhumps and Qpos
Mon. Not. R. Astron. Soc. 389, 1345–1352 (2008) doi:10.1111/j.1365-2966.2008.13641.x RR Pictoris: an old nova showing superhumps and QPOs L. Schmidtobreick,1 C. Papadaki,1,2 C. Tappert3 and A. Ederoclite1 1European Southern Observatory, Casilla 19001, Santiago 19, Chile 2Vrije Universteit Brussel, PLeinlaan 2, 1050 Brussels, Belgium 3Departamento de Astronom´ıa y Astrof´ısica, Pontificia Universidad Catolica,´ Casilla 306, Santiago 22, Chile Accepted 2008 June 23. Received 2008 June 20; in original form 2008 April 2 ABSTRACT We present time-resolved V photometry of the old nova RR Pictoris (RR Pic). Apart from the hump-like variability, the light curves show the strong flickering and random variation typical for RR Pic. We do not find any convincing evidence for the previously reported eclipse. The extrapolated eclipse phase coincides with a broad minimum, but comparing the overall shape of the light curve suggests that the eclipse should actually be located around phase 0.2. The orbital period which we derive from these data agrees well with the old one, any uncertainty is too small to account for the possible phase shift. Apart from the 3.48 h period, which is usually interpreted as the orbital one, we find an additional period at P = 3.78 h, which we interpret as the superhump period of the system; the corresponding precession period at 1.79 d is also present in the data. We also find indications for the presence of a 13 min quasi-periodic oscillation. Key words: accretion, accretion discs – stars: individual: RR Pic – novae, cataclysmic variables.