ASTRONOMİ Terimleri
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Luminous Blue Variables
Review Luminous Blue Variables Kerstin Weis 1* and Dominik J. Bomans 1,2,3 1 Astronomical Institute, Faculty for Physics and Astronomy, Ruhr University Bochum, 44801 Bochum, Germany 2 Department Plasmas with Complex Interactions, Ruhr University Bochum, 44801 Bochum, Germany 3 Ruhr Astroparticle and Plasma Physics (RAPP) Center, 44801 Bochum, Germany Received: 29 October 2019; Accepted: 18 February 2020; Published: 29 February 2020 Abstract: Luminous Blue Variables are massive evolved stars, here we introduce this outstanding class of objects. Described are the specific characteristics, the evolutionary state and what they are connected to other phases and types of massive stars. Our current knowledge of LBVs is limited by the fact that in comparison to other stellar classes and phases only a few “true” LBVs are known. This results from the lack of a unique, fast and always reliable identification scheme for LBVs. It literally takes time to get a true classification of a LBV. In addition the short duration of the LBV phase makes it even harder to catch and identify a star as LBV. We summarize here what is known so far, give an overview of the LBV population and the list of LBV host galaxies. LBV are clearly an important and still not fully understood phase in the live of (very) massive stars, especially due to the large and time variable mass loss during the LBV phase. We like to emphasize again the problem how to clearly identify LBV and that there are more than just one type of LBVs: The giant eruption LBVs or h Car analogs and the S Dor cycle LBVs. -
Analysis of Eclipsing Binary Data
analysis of eclipsing binary data A.E. Lynas-Gray and C. Causer October 2012 AS33 1 Introduction The purpose of this experiment is to verify physical and geometric characteristics of an eclipsing binary already published in the literature, using radial velocity and light curves provided. In carrying out the experiment, the most important thing is to appreciate how the masses, radii, shapes, temperatures and orbits of the two stars determine the observed light and radial velocity variations. The book by Hilditch (2001) is an excellent introduction to binary stars and is recommended reading. Once the period has been determined, masses, radii and effective temperatures of both components are estimated using a “back of an envelope” calculation; these results are then used as a starting ap- proximation in a light and radial velocity curve synthesis code. The idea is to reproduce observed light and radial velocity curves, but in practice “back of the envelope” results will need adjustment before a good agreement with observation is achieved. At the time of writing, only data for R Canis Majoris are provided. 2 Initial setup Begin by creating a xterm window in which commands can be typed. The window is created using the Mouse to click on the large “X” in the middle of the dock on the bottom of your screen. The large “X” may bob up and down a bit before the window appears. The steps detailed below provide the setup necessary for experiments carried out in the Astrophysics Laboratory. The .profile, .bashrc, .cups/lpoptions and .Xdefaults files in your home directory are changed as a result of carrying out steps listed below; if these files have been previously setup to carry out an experiment in another laboratory, please consult a demonstrator before proceeding. -
PHOTOMETRIC and SPECTROSCOPIC STUDY of R Cma*
PHOTOMETRIC AND SPECTROSCOPIC STUDY OF R CMa* K. R. RADHAKRISHNAN, M. B. K. SARMA, and K. D. ABHYANKAR Centre of Advances Study in Astronomy, Osmania University, Hyderabad, India (Received 19 July, 1983) Abstract. UBFlight curves and spectrograms of RCMa obtained with the 48-inch telescope of Japal- Rangapur Observatory during 1980-82 have been used for deriving the eclipse and orbital elements as well as the absolute dimensions of the components. The primary is found to be a Main-Sequence F2V star of mass 1.52 M and the secondary a subgiant star of spectral type G8 and mass 0.20 M which fills its Roche lobe, in agreement with Kopal and Shapley (1956) results, Kopal (1959), or Sahade's (1963) results. From a consideration of the possible evolution of this system it is concluded that a large fraction of the original mass of the secondary is lost from the system. A study of the period changes indicates the possible presence of a third component of mass of about 0.5 MQ which is most likely to be an M dwarf. 1. Introduction R Canis Majoris is the prototype of a group of Algol systems having very low mass function. It is known to exhibit peculiarities in its light curve that change from time to time and is thought to be surrounded by gas. It also shows changes in period which are not yet fully understood. Hence, this star was included in the photometric and spectroscopic observing programme of Japal-Rangapur Observatory. R CMa was observed photometrically with the 48-inch telescope in the standard UBV colors on 34 nights during 1980-82 covering nine minima. -
The Circumnuclear Ring (CNR) (11 Slides) – Quintuplet Proper Members (Qpms) (6 Slides) – Pistol Nebula (10 Slides)
SOFIA/FORCAST Observations of the Galactic Center Ryan M. Lau SOFIA Community Collaborators: T. L. Herter, M. R. Morris, E. E. Becklin, M. J. Hankins, Task Force Teletalks, J. D. Adams, G. E. Gull, C. P. Henderson, J. Schoenwald February 6, 2013 SOFIA/FORCAST Observations of the Galactic Center R. M. Lau Talk Outline • Background – The Galactic Center – Observations • Results and Science – The Circumnuclear Ring (CNR) (11 slides) – Quintuplet Proper Members (QPMs) (6 slides) – Pistol Nebula (10 slides) • Further Work 2 SOFIA/FORCAST Observations of the Galactic Center R. M. Lau The Galactic Center • ~500 pc unique region containing a 4,000,000 solar mass black hole, massive stars, supernovae, and star formation regions QC & Pistol • 10% of present SF activity in Galaxy occurs in GC yet only tiny fraction of a percent of volume in Galactic disk CNR 10 pc • Contains ~4/12 of the LBVs and ~90/240 of Wolf-Rayet stars in galaxy 3 SOFIA/FORCAST Observations of the Galactic Center R. M. Lau The Galactic Center: Inner 50 Pc • Circumnuclear Ring (CNR) – Dense ring of gas and dust surrounding Sgr A* by 1.4 pc • Quintuplet Cluster (QC) QC & Pistol – ~4 Myr cluster of hot, massive stars – Named after 5 bright IR sources within cluster (we observe 4 of them) • Pistol Nebula CNR – Asymmetric shell of dust and 10 pc gas surrounding the Pistol star – Appears to be shaped by 8 μm Spitzer/IRAC image of the inner interaction with QC winds 50 pc of the Galactic Center 4 SOFIA/FORCAST Observations of the Galactic Center R. -
Betelgeuse and the Crab Nebula
The monthly newsletter of the Temecula Valley Astronomers Feb 2020 Events: General Meeting : Monday, February 3rd, 2020 at the Ronald H. Roberts Temecula Library, Room B, 30600 Pauba Rd, at 7:00 PM. On the agenda this month is “What’s Up” by Sam Pitts, “Mission Briefing” by Clark Williams then followed by a presentation topic : “A History of Palomar Observatory” by Curtis Oort Cloud in Perspective. Credit NASA / JPL- Croulet. Refreshments by Chuck Caltech Dyson. Please consider helping out at one of the many Star Parties coming up over the next few months. For General information: the latest schedule, check the Subscription to the TVA is included in the annual $25 Calendar on the web page. membership (regular members) donation ($9 student; $35 family). President: Mark Baker 951-691-0101 WHAT’S INSIDE THIS MONTH: <[email protected]> Vice President: Sam Pitts <[email protected]> Cosmic Comments Past President: John Garrett <[email protected]> by President Mark Baker Treasurer: Curtis Croulet <[email protected]> Looking Up Redux Secretary: Deborah Baker <[email protected]> Club Librarian: Vacant compiled by Clark Williams Facebook: Tim Deardorff <[email protected]> Darkness Star Party Coordinator and Outreach: Deborah Baker by Mark DiVecchio <[email protected]> Betelgeuse and the Crab Nebula: Stellar Death and Rebirth Address renewals or other correspondence to: Temecula Valley Astronomers by David Prosper PO Box 1292 Murrieta, CA 92564 Send newsletter submissions to Mark DiVecchio th <[email protected]> by the 20 of the month -
Seeing the Light: the Art and Science of Astronomy
Chapter 1 Seeing the Light: The Art and Science of Astronomy In This Chapter ▶ Understanding the observational nature of astronomy ▶ Focusing on astronomy’s language of light ▶ Weighing in on gravity ▶ Recognizing the movements of objects in space tep outside on a clear night and look at the sky. If you’re a city dweller Sor live in a cramped suburb, you see dozens, maybe hundreds, of twin- kling stars. Depending on the time of the month, you may also see a full Moon and up to five of the eight planets that revolve around the Sun. A shooting star or “meteor” may appear overhead. What you actually see is the flash of light from a tiny piece of comet dust streaking through the upper atmosphere. Another pinpoint of light moves slowly and steadily across the sky. Is it a space satellite, such as the Hubble Space Telescope, or just a high-altitude airliner? If you have a pair of binoculars, you may be able to see the difference. Most air- liners have running lights, and their shapes may be perceptible. If you liveCOPYRIGHTED in the country — on the seashore MATERIAL away from resorts and develop- ments, on the plains, or in the mountains far from any floodlit ski slope — you can see thousands of stars. The Milky Way appears as a beautiful pearly swath across the heavens. What you’re seeing is the cumulative glow from millions of faint stars, individually indistinguishable with the naked eye. At a great observation place, such as Cerro Tololo in the Chilean Andes, you can see even more stars. -
![Arxiv:1601.03395V2 [Astro-Ph.SR] 12 Feb 2016 Telescope (Houck Et Al](https://docslib.b-cdn.net/cover/6531/arxiv-1601-03395v2-astro-ph-sr-12-feb-2016-telescope-houck-et-al-2006531.webp)
Arxiv:1601.03395V2 [Astro-Ph.SR] 12 Feb 2016 Telescope (Houck Et Al
Astronomy & Astrophysics manuscript no. wr102c_arxiv c ESO 2016 February 15, 2016 Analysis of the WN star WR 102c, its WR nebula, and the associated cluster of massive stars in the Sickle Nebula? M. Steinke1; 2, L. M. Oskinova1, W.-R. Hamann1, A. Sander1, A. Liermann3, and H. Todt1 1 Institute of Physics and Astronomy, University of Potsdam, 14476 Potsdam, Germany e-mail: [email protected], [email protected] 2 I. Physikalisches Institut der Universität zu Köln, Zülpicher Straße 77, 50937 Köln, Germany 3 Leibniz Institute for Astrophysics Potsdam (AIP), An der Sternwarte 16, 14482 Potsdam, Germany Received 04 November 2015; accepted ABSTRACT Context. The massive Wolf-Rayet type star WR 102c is located near the Quintuplet Cluster, one of the three massive star clusters in the Galactic Centre region. Previous studies indicated that WR 102c may have a dusty circumstellar nebula and is among the main ionising sources of the Sickle Nebula associated with the Quintuplet Cluster. Aims. The goals of our study are to derive the stellar parameters of WR 102c from the analysis of its spectrum and to investigate its stellar and nebular environment. Methods. We obtained observations with the ESO VLT integral field spectrograph SINFONI in the K-band, extracted the stellar spectra, and analysed them by means of stellar atmosphere models. Results. Our new analysis supersedes the results previously reported for WR 102c. We significantly decrease its bolometric luminosity and hydrogen content. We detect four early OB type stars close to WR 102c. These stars have radial velocities similar to that of WR 102c. -
Mag Sep PA Spectra Colors Seen Luminosity a 7.3 N/A N/A A1 V W 60 B 8.2 62 7 B 25 C 7.1 302 243 W 70 Observations: Observed at 104X
33 Doubles in Canis Major and Canis Minor Observed 1988-1996 with a C-8 (Celestron) from Columbia, Missouri (USA) and Kansas City, Missouri. Observer: Richard Harshaw Dates and sky conditions were not logged at this time in my observations. South 516 (HD 44144; SAO 171562) Rating: 3 Position: 0619-2459 Year of last measure: 1959 Assumed distance (l.y.): 770 Assumed luminosity (suns): 155 Mag Sep PA Spectra Colors Seen Luminosity A 7.3 n/a n/a A1 V W 60 B 8.2 62 7 B 25 C 7.1 302 243 W 70 Observations: Observed at 104x. Rich field. Notes: Hipparcos/Tycho data show different distances for these stars; they may be an optical system. The stars have different proper motions. South 518 (ADS 5034; HD 45016; SAO 151462) Rating: 2 Position: 0624-1614 Year of last measure: 1917 Assumed distance (l.y.): 890 Assumed luminosity (suns): 123 Mag Sep PA Spectra Colors Seen Luminosity A 7.0 n/a n/a A9 V W 100 B 8.6 16 88 A B 23 Observations: Observed at 83x. Rich field. Notes: Hipparcos/Tycho data show different distances for these stars; they may be an optical system. h3863 (ADS 5128; HD 45941; SAO 171831) Rating: 3 Position: 0629-2236 Year of last measure: 1959 Assumed distance (l.y.): 1,190 Assumed luminosity (suns): 237 Mag Sep PA Spectra Colors Seen Luminosity A 6.8 n/a n/a A2 V Y 200 B 8.7 3 119 Y 37 Observations: Observed at 280x. Rich field. Notes: First measure: 2.7" @ 119 (Doolittle). -
The Agb Newsletter
THE AGB NEWSLETTER An electronic publication dedicated to Asymptotic Giant Branch stars and related phenomena Official publication of the IAU Working Group on Red Giants and Supergiants No. 286 — 2 May 2021 https://www.astro.keele.ac.uk/AGBnews Editors: Jacco van Loon, Ambra Nanni and Albert Zijlstra Editorial Board (Working Group Organising Committee): Marcelo Miguel Miller Bertolami, Carolyn Doherty, JJ Eldridge, Anibal Garc´ıa-Hern´andez, Josef Hron, Biwei Jiang, Tomasz Kami´nski, John Lattanzio, Emily Levesque, Maria Lugaro, Keiichi Ohnaka, Gioia Rau, Jacco van Loon (Chair) Editorial Dear Colleagues, It is our pleasure to present you the 286th issue of the AGB Newsletter. A healthy 30 postings are sure to keep you inspired. Now that the Leuven workshop has happened, we are gearing up to the IAU-sponsored GAPS 2021 virtual discussion meeting aimed to lay out a roadmap for cool evolved star research: we have got an exciting line-up of new talent as well as seasoned experts introducing the final session – all are encouraged to contribute to the meeting through 5-minute presentations or live discussion and the White Paper that will follow (see announcement at the back). Those interested in the common envelope process will no doubt consider attending the CEPO 2021 virtual meeting on this topic organised at the end of August / star of September. Great news on the job front: there are Ph.D. positions in Bordeaux, postdoc positions in Warsaw and another one in Nice. Thanks to Josef Hron and P´eter Abrah´am´ for ensuring the continuation of the Fizeau programme for exchange in the field of interferometry. -
The Messenger
Czech Republic joins ESO The Messenger Progress on ALMA CRIRES Science Verification Gender balance among ESO staff No. 128 – JuneNo. 2007 The Organisation The Czech Republic Joins ESO Catherine Cesarsky The XXVIth IAU General Assembly, held This Agreement was formally confirmed (ESO Director General) in Prague in 2006, clearly provided a by the ESO Council at its meeting on boost for the Czech efforts to join ESO, 6 December and a few days thereafter by not the least in securing the necessary the Czech government, enabling a sign- I am delighted to welcome the Czech public and political support. Thus our ing ceremony in Prague on 22 December Republic as our 13th member state. From Czech colleagues used the opportunity (see photograph below). This was impor- its size, the Czech Republic may not be- to publish a fine and very interesting pop- tant because the Agreement foresaw long to the ‘big’ member states, but the ular book about Czech astronomy and accession by 1 January 2007. With the accession nonetheless marks an impor- ESO, which, together with the General signatures in place, the agreement could tant point in ESO’s history and, I believe, Assembly, created considerable media be submitted to the Czech Parliament in the history of Czech astronomy as well. interest. for ratification within an agreed ‘grace pe- The Czech Republic is the first of the riod’. This formal procedure was con- Central and East European countries to On 20 September 2006, at a meeting at cluded on 30 April 2007, when I was noti- join ESO. The membership underlines ESO Headquarters, the negotiating teams fied of the deposition of the instrument of ESO’s continuing evolution as the prime from ESO and the Czech Republic arrived ratification at the French Ministry of European organisation for astronomy, at an agreement in principle, which was Foreign Affairs. -
Clusters Nebulae & Galaxies
CLUSTERS, NEBULAE & GALAXIES A NOVICE OBSERVER’S HANDBOOK By: Prof. P. N. Shankar PREFACE In the normal course of events, an amateur who builds or acquires a telescope will use it initially to observe the Moon and the planets. After the thrill of seeing the craters of the Moon, the Galilean moons of Jupiter and its bands, and the rings of Saturn he(*) is usually at a loss as to what to do next; Mars and Venus are usually disappointing as are the stars (they don’t look any bigger!). If the telescope had good resolution one could observe binaries, but alas, this is often not the case. Moreover, at this stage, the amateur is unlikely to be willing to do serious work on variable stars or on planetary observations. What can he do with his telescope that will rekindle his interest and prepare him for serious work? I believe that there is little better for him to do than hunt for the Messier objects; this book is meant as a guide in this exciting adventure. While this book is primarily a guide to the Messier objects, a few other easy clusters and nebulae have also been included. I have tried, while writing this handbook, to keep in mind the difficulties faced by a beginner. Even if one has good star maps, such as those in Norton’s Star Atlas, a beginner often has difficulty in locating some of the Messier objects because he does not know what he is expected to see! A cluster like M29 is a little difficult because it is a sparse cluster in a rich field; M97 is nominally brighter than M76, another planetary, but is more difficult to see; M33 is an approximately 6th magnitude galaxy but is far more difficult than many 9th magnitude galaxies. -
High Resolution Infrared Imaging and Spectroscopy of the Pistol Nebula
High Resolution Infrared Imaging and Spectroscopy of the Pistol Nebula: Evidence for Ejection1 Donald F. Figer2,3, Mark Morris2,8, T. R. Geballe4, R. Michael Rich2, Eugene Serabyn5, Ian S. McLean2, R. C. Puetter6, Amos Yahil7 ABSTRACT We present new infrared images, obtained with the Hubble Space Telescope (HST) Near-infrared Camera and Multi-object Spectrometer (NICMOS), and Br-α (4.05 µm) spectroscopy, obtained using CGS4 on UKIRT, of the Pistol Star and its associated nebula. We find strong evidence to support the hypothesis that the Pistol Nebula was ejected from the Pistol Star. The Pa-α (1.87 µm) NICMOS image shows that the nebula completely surrounds the Pistol Star, although the line intensity is much stronger on its northern and western edges. The Br-α CGS4 spectra show the classical ring-like signature of quasi-spherical −1 expansion. The blueshifted emission (Vmax ≈ −60 km s ) is much weaker −1 than the redshifted emission (Vmax ≈ +10 km s ), where the velocities are with respect to the velocity of the Pistol Star; further, the redshifted emission spans a very narrow range of velocities, i.e., it appears “flattened” in the 1Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc. under NASA contract No. NAS5-26555. arXiv:astro-ph/9906479v1 29 Jun 1999 2Division of Astronomy, Department of Physics & Astronomy, University of California, Los Angeles, 405 Hilgard Avenue, Los Angeles, CA 90095-1562; fi[email protected], [email protected], [email protected], [email protected] 3Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 4Gemini Observatory, 670 N.