H. W. Duerbeck's research while affiliated with Vrije Universiteit Brussel and other places

Publications (319)

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The history of the Hoher List Observatory near Daun in the Eifel region (i.e. the field station of the Astronomical Observatory - later the Argelander Institute of Astronomy - of the University of Bonn) is described from the 1950s until 2012.
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In 1871, the Belgian astronomer Jean-Charles Houzeau developed a new approach to determine the solar parallax. His ``heliometer with unequal focal lengths" produces a large and a small solar image, as well as a large and small image of Venus. Making the small solar and the large Venus image coincide yields a measure of the distance of the centers o...
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The previous Transits of Venus Working Group report #6, covering the time mid-2006 to mid-2009, was published by the undersigned in the Journal of Astronomical History and Heritage, Vol. 12, p. 254 (2009). The present report #7, covering the time up to mid-2011, has been prepared for the Reports presented at the IAU General Assembly in Beijing, Aug...
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In 1998 the Journal of Astronomical History and Heritage (JAH2) was launched as a new outlet for those wishing to publish papers on the history of astronomy. The journal has since developed rapidly and become an important publication venue for those conducting research in all fields of historical astronomy, including aspects of Asian and Oriental a...
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The Centre for Astronomy at James Cook University (JCU) in Australia has been offering totally internet-delivered Master of Astronomy degrees since 2003 and Doctor of Astronomy and Ph.D. degrees since 2004. In 2005 a new dimension was added with unique offerings in the history of astronomy at both Masters and Doctoral levels. With the aid of 1 full...
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Report on activities of the Working Group for the History of Astronomy and bibliography of publications by its members in the year 2009. - Published in: Mitteilungen der Astronomischen Gesellschaft 93 (2010), p. 21-30
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Report on activities of the Working Group for the History of Astronomy and bibliography of publications by its members in the year 2008. - Published in: Mitteilungen der Astronomischen Gesellschaft 92 (2009), p. 25-34
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This article gives a brief overview of 400 years of research in the field of novae and related stars. Important objects, first applications of various observing techniques, and early ideas of the interpretation of phenomena are listed. Also, the historical evolution of the classification of novae and related stars (supernovae, dwarf novae), as well...
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This issue of AN contains the proceedings of the Special Colloquium ``400 years of telescopes -- the European contribution'', which formed part of the JENAM 2008 conference in Vienna, Austria. Subjects covered are the history of the telescope, European observatories, telescopes and astronomers, as well as archaeoastronomy.
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The method and results of the computation of the model atmospheres and spectral energy distributions of chemically peculiar stars are discussed. The models and spectra are computed with special consideration of the particular problems encountered for peculiar and hydrogen deficient stars in the later stages of evolution. We present some computed mo...
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Report on activities of the Working Group for the History of Astronomy and bibliography of publications by its members in the year 2007. - Published in: Mitteilungen der Astronomischen Gesellschaft 91 (2008), p. 19-28
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Radial velocity measurements and sine-curve fits to the orbital velocity variations are presented for 14 close binary stars, S Ant, TT Cet, TW Cet, AA Cet, RW Dor, UX Eri, YY Eri, BV Eri, CT Eri, SZ Hor, AD Phe, TY Pup, HI Pup, and TZ Pyx. All are double-lined binaries, and all except the last one are contact binaries. The orbital data must be cons...
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CCD UBVRi photometry of the final helium flash object V4334 Sgr (Sakurai's object) carried out during 1997–1999 is presented, and the light curve from its prediscovery rise to the dust obscuration phase is constructed. The optical light curve can be divided into four sections, the rise to maximum, the maximum, the dust onset, and the massive dust s...
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Radial velocity measurements and sine-curve fits to the orbital velocity variations are presented for nine contact binaries: V1464 Aql, V759 Cen, DE Oct, MW Pav, BQ Phe, EL Aqr, SX Crv, VZ Lib, and GR Vir. For the first five of these, our observations are the first available radial velocity data. For the three remaining radial velocity variables, C...
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The Journal of Astronomical Data (JAD) was founded in 1995 with the intention to provide a forum for publishing original astronomical research data in machine-readable form. The Journal accepts observational data as well as data from theoretical research, reduction software and computer code, complete descriptions of new instruments, Ph.D. thesises...
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We give a concise outline on astronomical activities carried out in Germany during the time of the Third Reich (1933-1945), both at university observatories and in research institutions funded by other organizations.
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This publication contains the Proceedings of a Colloquium on the development of solar research, supplemented with a number of papers which were written especially for this book. The volume contains 14 papers dealing with archeo-astronomy related to the Sun, solar cults, and (mainly) solar research. Ten papers are written in English, the remaining f...
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This book collects about 15 papers (most of them by one single author) on Einstein and the history of general relativity (GR) and the foundations of relativistic cosmology. The matter not only deals with Einstein and his times, but also with pre-GR ideas, and with the interplay of Einstein and his colleagues (opposing as well as supporting personal...
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Radial-velocity measurements and sine-curve fits to the orbital velocity variations are presented for 14 close binary stars, S Ant, TT Cet, TW Cet, AA Cet, RW Dor, UX Eri, YY Eri, BV Eri, CT Eri, SZ Hor, AD Phe, TY Pup, HI Pup and TZ Pyx. All are double-lined binaries and all except the last one are contact binaries. The orbital data must be consid...
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A short overview of the bibliography of astronomy from the time of Weidler (1755) to the end of the 19th century is given. Walter Wislicenus studied astronomy in Leipzig and Strasbourg, took part in the German Transit of Venus expedition to Bahia Blanca in 1882, finished his PhD, became an assistant at Strasbourg Observatory, and afterwards a priva...
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We briefly review the nebular research in the 19th and early 20th century, and the rôle played by the newly founded Strasbourg Observatory in this field. The life of Carl Wirtz (1874–1939) is outlined. His studies in Bonn, his work in Vienna and Hamburg, his astronomical activity in Strasbourg from 1903–1916, at the war headquarters in Berlin in th...
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We give an overview of the personnel of Strasbourg Observatory between 1872 and 1919, by making use of official documents, recollections of Wilhelm Foerster and Hermann Kobold, reports and bibliographies. The careers of almost all scientific workers are briefly described, and supplemented by illustrations. In addition, the major projects carried ou...
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During World War II, the Reichsuniversität Strassburg was installed by the German authorities and Johannes Hellerich (1888–1963) was appointed director of the Observatory. A review of his life and his astronomical career as an assistant and professor in Kiel, Hamburg, Strasbourg, and Muenster is given. His activity in Strasbourg from mid-1941 to mi...
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The Catalog and Atlas of Cataclysmic Variables has been a staple of the CV community for over 10 years. The catalog has grown from 751 CVs in 1993 to 1600 CVs at present. The catalog became a ``living'' edition in 2001, and its contents have been continually updated since that time. Effective 27 January 2006, the catalog will transition to an archi...
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The observed rate and spatial distribution of galactic novae can be explained with the concept of two nova, populations, the disc novae of faster outburst development, and the slower bulge novae. Similar populations seem to exist in nearby galaxies. The space density of galactic novae depends strongly on the recurrence time, which is unknown and ma...
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Originally based on a workshop on ``Development of Solar Research'', held in Freiburg/Breisgau, this book contains articles on megalithic structures, the Nebra sky-disk, ancient sun cults, the observation of sunspots, the photography of the sun during eclipses, eclipse maps and expeditions, solar telescopes, solar physics during the Nazi era, archi...
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WX Cet (Nova Cet 1963) - a SU UMa type dwarf nova - was observed in 2001 and in 2004-2005 during superoutburst and subsequent quiescence. This paper presents the complete light curve material in digital form, and provides a number of nightly-averaged BVR CCD frames of the WX Ceti field for calibration purposes.
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The different contributions of the present volume illuminate the interaction between Einstein and his colleagues when the foundations of modern cosmology were laid: First, the relativistic effects in the solar system, the gravitational redshift in the solar spectrum, and Einstein's relations with Freundlich and Eddington. Second, the cosmological m...
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These Proceedings contain a selection of presentations and research papers emanating from meetings of the Astronomical Archives and Transits of Venus Working Groups of Commission 41, and from presentations at the last three IAU General Assemblies. Some additional reports related to the topic of this book have also been added. The first part of the...
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These Proceedings contain a selection of presentations and research papers emanating from meetings of the Astronomical Archives and Transits of Venus Working Groups of Commission 41, and from presentations at the last three IAU General Assemblies. Some additional reports related to the topic of this book have also been added. The first part of the...
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This chapter is providing an alphabetical list of Strasbourg scientific personnel from foundation up to Year 2000.
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On June 16, 1754, the birth of the second son of its leading physician was registered in the "Militärmatriken" of the Invalides' Hospital at Pest, Hungary. The father was Joseph Zach from Olmüutz and the mother Clara née Sontag. The son received the names Joannes Franciscus Xaverius Vitus Fridericus, and later became a geodesist and astronomer. For...
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In 1871, the Belgian astronomer Houzeau suggested applying a new heliometric device to measure the position of Venus transiting the solar disk. This ``heliometer with unequal focal lengths'' produces a large and a small solar image, as well as a large and small image of Venus. Making the small solar and the large Venus image coincide would yield a...
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WX Eri is an eclipsing binary system for which one component was reported to show delta Scuti type pulsations with periods close to integer fractions of the orbital period. This makes it an interesting candidate for investigating the interaction between binarity and pulsation and a potential new member of the recently defined group of mass-accretin...
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Photometric V and B CCD time-series observations of WX Eri, obtained at the South African Astronomical Observatory (SAAO), Beersel Hills Observatory (BH), Las Campanas Observatory (LCO), European Southern Observatory (ESO), Sternwarte Hoher List (HOLI/HOLIr) and at Esteve Duran Observatory (EDO) during 2001 and early 2002. The measurements from the...
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The 18th volume of the Acta Historica Astronomiae is at the same time the sixth collection of essays on the history of astronomy ("Beitræge zur Astronomiegeschichte, Band 6"), edited by the historians of astronomy W.R. Dick (Potsdam) and J. Hamel (Berlin). Besides a few short notices and book reviews, the book contains eight major articles, which d...
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Trumpler 24 is a comparatively poorly-studied young open cluster. To investigate the correlation between the Be phenomenon and the cluster age, and to study the stellar variability in Trumpler 24, CCD time-series observations were made in 2001, and spectra were obtained in 2002. The results reveal 21 new variable stars, including 3 eclipsing binari...
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A luminosity calibration of galactic novae indicates that all novae at brightness maximum radiate over-Eddington, and that speed- and light curve classes are intimately related. In later stages, the Balmer and [O III] line fluxes decline in similar ways for novae of all speed classes, except in slow ones where Balmer emission diminishes faster, and...
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We present the visual light curve, CCD images and spectra of V838 Mon after its eruption.
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The outburst of the recurrent nova IM Nor was followed photometrically and spectroscopically. In the beginning of the outburst, the spectrum of the nova belonged to the Fe II class, but after one month, it changed to the He/N class. Thus IM Nor is one of the hybrid novae, and has many spectroscopic similarities with CI Aql and T Pyx, the other two...
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We present 198 optical postoutburst spectra in digital form for 27 novae (23 classical, 4 recurrent). Broad wavelength coverage (between 320 and 1600 nm) has been emphasized at the expense of spectral resolution although the latter has been sufficient to resolve the emission lines. For many of the novae, the temporal coverage has been adequate to d...
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We present a large-scale galaxy catalogue for the red spectral region which covers an area of 5 000 square degrees. It contains positions, red magnitudes, radii, ellipticities and position angles of about 5.5 million galaxies. Together with the APM catalogue (4,300 square degrees) in the blue spectral region, this catalogue forms at present the lar...
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This issue of AN contains the proceedings of the Special Colloquium “European Astronomy in the 20th Century”, which formed part of the JENAM (2001) conference in Munich, Germany. Subjects covered are the history of γ-ray and radio astronomy, extragalactic research and compact objects, new media, southern observatories and ESO, as well as some archa...
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While the theoretical foundations of modern relativistic cosmology were laid, to a large extent, by European researchers like Einstein, de Sitter, Friedmann, Lemaître, and others, observational cosmology was (and to a large extent, still is) dominated by US astronomers, working at Lick and Mt. Wilson observatories. From today's viewpoint, Hubble ap...
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The 15th volume of the Acta Historica Astronomiae is at the same time the fifth collection of essays on the history of astronomy (Beitraege zur Astronomiegeschichte, Band 5), edited by the historians of astronomy W.R. Dick (Potsdam) and J. Hamel (Berlin). Besides a few short notices and book reviews, the book contains 11 major articles, which deal...
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A luminosity calibration of galactic novae indicates that all novae at brightness maximum radiate over‐Eddington, and that speed‐ and light curve classes are intimately related. In later stages, the Balmer and [O III] line fluxes decline in similar ways for novae of all speed classes, except in slow ones where Balmer emission diminishes faster, and...
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The outburst of the recurrent nova IM Nor was followed visually and spectroscopically. In the beginning of the outburst, the nova belonged to Williams’ Fe II class, but one month later, the spectrum changed to the He/N class. Thus IM Nor is a member of the hybrid class of novae, and has many spectroscopic similarities with CI Aql and T Pyx, the two...
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We present a spectroscopic study of the long-recurrence-time dwarf nova V 592 Herculis based on observations obtained during its August 1998 superoutburst. From the analysis of the radial velocities of the H$alpha$ emission line we find a most likely orbital period of 85.5 +/- 0.4 min, but the 91.2 +/- 0.6 min alias cannot be completely discarded....
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IAUC 7974 available at Central Bureau for Astronomical Telegrams.
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We present fits to 1–5 μm spectra of the dust shell around Sakurai's Object (V4334 Sgr) obtained over the period 1999 May to 2001 September, using the dusty modelling program. We find that the emission is consistent with carbon dust grains for which the optical properties are predominantly graphitic, and for which sizes range from ∼0.005 to ∼1–2 μm...
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We report further UKIRT spectroscopic observations of Sakurai's object (V4334 Sgr) made in 1999 April/May in the 1–4.75 μm range, and find that the emission is dominated by amorphous carbon at Td∼600 K. The estimated maximum grain size is 0.6 μm, and the mass lower limit is 1.7±0.2×10−8 M⊙ to 8.9±0.6×10−7 M⊙ for distances of 1.1–8 kpc. For 3.8 kpc...
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The Catalog and Atlas of Cataclysmic Variables (Edition 1: Downes & Shara; Edition 2: Downes, Webbink, & Shara) has been a valuable source of information for the cataclysmic variable community. However, the goal of having a central location for all objects is slowly being lost as each new edition is generated. There can also be a long time delay be...
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The optical photometric evolution of the final helium flash object V4334 Sgr from 1994 to 2001 is described. The rise to optical maximum (1994–1996) is characterized by a continuous increase of colour indices, indicating a slowly expanding, cooling pseudo-photosphere. This photosphere became stationary in 1997. In the following years, the object un...
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The photometric evolution of the final helium flash object V4334 Sgr from 1994 to 2001 is described. The rise to optical maximum (1994-1996) is characterized by a continuous increase of color indices, indicating a slowly expanding, cooling pseudo-photosphere. This photosphere became stationary in 1997. In the following years, the object underwent b...
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NGC6231 is a well-studied young open cluster with many variable stars. We present a long-term project to map the variability in NGC6231 and to monitor the stability of the pulsational frequencies and amplitudes. This paper reports new results based on CCD time-series data optimised for the bright beta Cep stars as well as data optimised for much fa...
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The evolution of the luminosity of nova shells in the century following the nova outburst is studied for the lines H-alpha, H-beta, and [O III]. About 1200 flux measurements from 96 objects have been collected from the literature, from unpublished observations, from the HST archive, or from new narrow-band filter imaging. For most objects, the dist...
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`Nova Aquilae No. 4'', discovered in 1919, later renamed V605 Aql, was recognized to be a final helium flash object only in the 1980s. Clayton and De Marco (1997) gave a detailed description of the available spectroscopic and photometric material. Here we try to re-analyze the photometric record. The photographic material is still available and has...
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IAUC 7799 available at Central Bureau for Astronomical Telegrams.
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Full-text available
NGC 6231 is a well-studied young open cluster hosting several variable stars. In the field six beta Cephei stars, several eclipsing binaries and one delta Scuti star are known (as well as a foreground delta Scuti star). In an ongoing effort to map and study the variability in NGC 6231, we present new results based on CCD time-series data optimised...
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An overview on the progress of theoretical and observational cosmology in the first half of the 20th century is given. We outline the Einstein, de Sitter and Friedmann-Lemaître models, and describe the quest for the observational confirmation of the de Sitter universe, as well as the first theoretical and observational work on the Friedmann-Lemaîtr...
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``Nova Aquilae No. 4'', discovered in 1919, later renamed V605 Aql, was recognized to be a final helium flash object only in the 1980s. Clayton and De Marco (1997) gave a detailed description of the available spectroscopic and photometric material. Here we try to re-analyze the photometric record. The photographic material is still available and ha...
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Full-text available
Theoretical spectral energy distributions are computed for a grid of hydrogen-deficient and carbon-rich model atmospheres with a range in T_eff of 4000-5500 K and log g of 1.0-0.0, using the technique of opacity sampling, and taking into account continuous, atomic line and molecular band absorption. The energy distributions are compared with the sp...
Article
Full-text available
The Catalog and Atlas of Cataclysmic Variables (Edition 1 - 1993) and Edition 2 - 1997) has been a valuable source of information for the cataclysmic variable (CV) community. However, the goal of having a central location for all objects is slowly being lost as each new edition is generated. There can also be a long time delay between new informati...
Article
An optical imaging study of recent 30 novae has been undertaken using both ground-based and space-based observations. Resolved shells have been detected around 9 objects in the ground-based data, while another four objects have shells detected by HST observations; for RW UMi, we fail to detect a shell which was observed five years earlier. Images i...
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An overview on the progress on theoretical and observational cosmology in the first half of the 20th century is given. We outline the Einstein, de Sitter and Friedmann-Lemaître models, and describe the quest for the observational confirmation of the de Sitter universe, as well as the first theoretical and observational work on the Friedmann-Lemaîtr...
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Full-text available
Theoretical spectral energy distributions were computed for a grid of hydrogen-deficient and carbon-rich model atmospheres of T(eff) in the range of 5000-6250 K and log g = 1.0 - 0.0 by the technique of opacity sampling, taking into account continuous, molecular band and atomic line absorption. These energy distributions were compared with the spec...
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Strömgren differential photometry of HD 168607 and HD 168625 collected during the previous 27 years is analysed. We bring to an end our quarter of a century monitoring of these objects and conclude that HD 168607 shows typical variability of an uneventful LBV, whereas HD 168625 remains to be classified as a variable hypergiant, or a marginally-dorm...
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We report here optical observations during the September/October 1998 outburst of the black hole candidate XTE J1550-564. CCD photometry was obtained for the optical counterpart with the 0.9m Dutch telescope at La Silla since the onset of this event. We analysed 211 U, V and i frames, from Sep 10 to Oct 23. Stochastic flaring activity was observed...
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We have performed a ROSAT follow-up observation of the X-ray transient SAX J1810.8-2609 on March 24, 1998 and detected a bright X-ray source (named RX J1810.7-2609) which was not detected during the ROSAT all-sky survey in September 1990. Optical-to-infrared follow-up observations of the 10 arcsec radius ROSAT HRI X-ray error box revealed one varia...