Messenger No. 32 (June 1983)

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1-3 (PDF)
R. M. West
Comets - Distant and Nearby

ADS BibCode:
1983Msngr..32....1W
Author(s)/Affiliation(s):
West, R. M.
AA(ESO)
Abstract:
With the recovery of Comet Halley on October 16, 1982, the interest in comets has received a new impetus. Everybody knows this famous comet and when the predicted orbit for its Current return was published in 1977, several astronomers started a systematic search to recover the objecl.
1-1 (PDF)
ESO
Prof. Otto Heckmann, 1901-1983

ADS BibCode:
1983Msngr..32....1.
Author(s)/Affiliation(s):
ESO
AA(ESO)
3-6 (PDF)
J. Caplan, L. Deharveng
Absolute Photometry of HII Regions

ADS BibCode:
1983Msngr..32....3C
Author(s)/Affiliation(s):
Caplan, J.; Deharveng, L.
AA(Observatoire de Marseille) AB(Observatoire de Marseille)
Abstract:
Today it is possible to observe HII regions not only in the visible part of the spectrum, but also in the radio, millimetre, infrared, and ultraviolet ranges. Combining photometrie data from several of these wavelengths helps us to understand the properties of HII regions and of their exciting star clusters. But often, rather surprisingly, the measurements are quite good at these "exotic" wavelengths but only qualitative, or of low accuracy, in the optical region.
6-10 (PDF)
R. Schoembs
Cn-Orionis - Cooperative Observations for 24-HOURS/DAY Monitoring

ADS BibCode:
1983Msngr..32....6S
Author(s)/Affiliation(s):
Schoembs, R.
AA(Universitäts-Sternwarte, Munich)
Abstract:
When modern technologies open the possibility of astronomical measurements in wavelength regions from y rays to the ultraviolet and from the infrared to the radio band, the visual range shrinks to a very small interval in the flux diagrams. However, the time of use of the necessarily complex and expensive instruments is very limited. Observing runs of an hour or so are of little use for the investigation of astronomical events like stellar outbursts which evolve with timescales of days. So even optical telescopes with apertures below 1m still have a relevance for long-time observational programmes. An interesting group of objects which is known to show variations in the time scale mentioned is the class of cataclysmic variables (CV). The general model for all members consists of a Roche lobe filling secondary (near the main sequence) which transfers matter via the Lagrangian point L1 to the highly evolved primary, a white dwarf or neutron star. Due to its angular momentum the mass stream does not impact but rather surrounds the small primary, building a more or less circular accretion disko A hot bright spot is produced where the initial stream collides with the already circulating material of the disko By angular momentum exchange part of the disk material finally reaches the primary. The increasing amount of information from all kind of observations has made clear that the class of CVs comprises many kinds of interesting objects like X-ray sourees, oblique magnetic rotators with synchronized rotation or with rotation with critical periods of up to 10s and systems emitting highly polarized radiation from strong magnetic fjelds of 107 G. Prominent properties of CVs are eruptions with a large range of amplitudes. The more violent events, nova eruptions (> 10 mag) are caused by thermonuclear runaways on the primary. This explanation is quite secure although the nova explosion of a system is so rare that until now it was observed only once for an individual object. The dwarf novae brighten up by a factor of 10 or 100 for a few days only, but every 10 to 1,000 days. In spite of the more detailed observations, there is no generally accepted explanation for their eruption.
References:
Bath, G. T.: 1973, Nature Phys. Sei. 246,84.
Meyer, F., Meyer-Hofmeister, E.: 1981, Astron. Astrophys. 104, L10.
Osaki, Y.: 1974, PASP 26,429.
Patterson, J.: 1981, Astrophys. J. Suppl. 45. 517.
Schoembs, R.: 1982, Astron. Astrophys. 115,190.
Vogt, N.: 1983, Astron. Astrophys. 118, 95.
Warner, S.: 1983, MNASSA, preprint.
11-15 (PDF)
J. Melnick
R136 : the Core of the Ionizing Cluster of 30-DORADUS

ADS BibCode:
1983Msngr..32...11M
Author(s)/Affiliation(s):
Melnick, J.
AA(ESO)
Abstract:
I first read that R136 contained a supermassive object some time ago in the Sunday edition of the Chilean daily newspaper EI Mercurio, where it was announced that ... "European astronomers discover the most massive star in the Universe!". Since EI Mercurio is almost always wrang I did not take the announcement very seriously until the paper by Feitzinger and Co-workers (henceforth the Bochum graup) appeared in Astronomy and Astrophysics in 1980. More or less simultaneously with the publication of these optical observations, a graup of observers from the University of Wisconsin, headed by J. Cassinelli (henceforth the Wisconsin group) reached the same Conclusion on the basis of ultraviolet observations obtained with the International Ultraviolet Explorer (IUE).
References:
To make the text easier to read, I have not included formal
references. Complete references to most of the papers I have
mentioned can be found in the article on R136a by SchmidtKaler
and Feitzinger published in the proceedings of the ESO
conference "The Most Massive Stars". All other articles I refer
to are preprints kindly sent to me by the authors.
15-20 (PDF)
D. Dravins
Stellar Granulation and the Structure of Stellar Surfaces

ADS BibCode:
1983Msngr..32...15D
Author(s)/Affiliation(s):
Dravins, D.
AA(Lund Observatory)
Abstract:
Convection in Stars Stellar convection is a central but poorly understood parameter In the construction of stellar models and the determination of stellar ages, influencing both the energy transport through the atmosPh.ere and the replenishment 01 nuclear fuels in the core. The motlons in stellar convection zones probably supply the energy for generating magnetic fields, heating stellar chromospheres and coronae, driving stellar winds, and for many other nonthermal phenomena. The inhomogeneous structure of velocity fields on stellar surfaces complicates the accurate determination of stellar radial velocities. Further, the temperature inhomogeneities on stellar surfaces induce molecular abundance inhomogeneities and entangle the accurate determination of chemical abundances.
References:
Beckers, J. M., Bridges, C. A., Gilliam, L. B.: 1976, A High Resolution
Spectral Atlas of the Solar Irradiance from 380 to 700 Nanometers,
Sacramenlo Peak Observalory.
Dravins, D.: 1981, in M. H. Ulrich, K. Kjär (eds.) ESO Conf. Seientifie
Importanee of High Angular Resolution at Infrared and Optieal
Wavelengths, p. 295.
Dravins, D.: 1982a, Ann. Rev. Astron. Astrophys. 20,61.
Dravins, D.: 1982b, in C. M. Humphries (ed.) Instrumentation for
Astronomy with Large Optieal Telescopes, p. 229.
Dravins, D., Lind, J.: 1983, to be published.
Dravins, D., Lindegren, L., Nordlund, A.: 1981, Astron. Astrophys. 96,
345.
Enard, D.: 1977, The Messenger No. 11, p. 22.
Enard, D.: 1979, The Messenger No. 17, p. 32.
Enard, D.: 1981, The Messenger No. 26, p. 22.
Gray, D. F.: 1980, Astrophys. J. 235, 508.
Gray, D. F.: 1982, Astrophys. J. 255, 200.
Gray, D. F.: 1983, Publ. Astron. Soe. Paeifie, submitted.
Hanbury Brown, R.: 1974, The Intensity Interferometer.
Nordlund, A.: 1978, in A. Reiz, T. Andersen (eds.) AstronomiealPapers
Dedieated to Bengt Strämgren, p. 95.
Nordlund, A.: 1982, Astron. Astrophys. 107, 1.
20-22 (PDF)
R. Gathier
Distances to Planetary Nebulae

ADS BibCode:
1983Msngr..32...20G
Author(s)/Affiliation(s):
Gathier, R.
AA(Kapteyn Astronomicallnstitute, Groningen, The Netherlands)
Abstract:
When astronomers want to determine the properties of an object in the universe, they need a reliable distance to that object. Consequently there always has been much effort to find methods for distance determination. In the case of planetary nebulae, distances are very difficult to determine. Several methods have been tried but individual distances in general are still uncertain by a factor of two to three, sometimes even more. We have used an in principle powerful method, the "extinction method" to derive accurate distances for about 10 planetary nebulae.
20-20 (PDF)
ESO
List of Preprints Published at ESO Scientific Group

ADS BibCode:
1983Msngr..32...20.
Author(s)/Affiliation(s):
ESO
AA(ESO)
22-22 (PDF)
ESO
Announcement of CERN Symposium - Large scale Structure of the Universe - Cosmology and Fundamental Physics - 1983NOV21-25 - Geneva

ADS BibCode:
1983Msngr..32...22S
Author(s)/Affiliation(s):
ESO
AA(ESO)
23-25 (PDF)
W. E. Celnik
H Alpha Observations of the Rosette Nebula and the Distribution of Interstellar Dust

ADS BibCode:
1983Msngr..32...23C
Author(s)/Affiliation(s):
Celnik, W. E.
AA(Astronomisches Institut, Ruhr-Universität Bochum)
Abstract:
The Rosette nebula is a well-known HII region in the constellation of Monoceros with a diameter of more than 2°. The nebula has a nearly circular shape forming a ring around a deep local intensity minimum (Fig. 1). The open star cluster NGC 2244 is visible within the HI1 region, containing early-type stars which emit enough hard UV radiation to ionize the nebula. Adjacent to the north-eastern border of the Rosette nebula there is the large supernova remnant of the Monoceros Loop.
25-28 (PDF)
J. V. Clausen
The Copenhagen Binary Project

ADS BibCode:
1983Msngr..32...25C
Author(s)/Affiliation(s):
Clausen, J. V.
AA(Copenhagen University Observatory)
Abstract:
While this short contribution is written and the rain has been POuring down in Denmark, surely setting up new records, we strongly hope for an unbroken long series of clear, stable photometric nights at La Silla. The last long-term (40 nights) photometric observing run for our eclipsing binary project at the Danish 50 cm telescope began a few nights ago. Last - at least with the characteristically shaped, well-known uvby photometer mounted at the manually operated telescope, a combination which through the years has demonstrated its accuracy and reliability in a large number of projects in different fields of galactic research.
28-29 (PDF)
P. Giordano, E. Maurice
Some News about the Coude Spectrograph of the ESO 1.52-M Telescope

ADS BibCode:
1983Msngr..32...28G
Author(s)/Affiliation(s):
Giordano, P.; Maurice, E.
AA(ESO) AB(ESO)
Abstract:
The coude speetrograph was installed at La Silla early in 1969; the first referenee speetra were obtained in May 1969. Since the beginning of the routine observations, several thousands of speetra have been taken, 8,127 with eamera 1 at 20.1 or 31.3 Almm-1, 12,913 with camera 2 at 12.3 or 19.4 A/ mm^-1 and 2,058 with eamera 3 at 2.6, 3.3 or 5.1 A/mm^-1 . After 14 years of often heavy duty, it appeared neeessary to do a eareful overhaul of the speetrograph. Some signifieant improvements were done during this 14-year period, but some important eomponents had not been touehed during a very long time, for instanee the two elosed eameras 1 and 2. The overhaul was done between August 1982 and February 1983 under the supervision of P. Giordano and with the help of B. Buzzoni. A. Torrej6n, E. Araya and J. Perez aetively partieipated in the foeussing phase and P. Alvarez and J. Torres, from the workshop, in the meehanieal phase.
29-30 (PDF)
P. Gammelgaard, L. K. Kristensen
Fine Structure Lightcurve of 51 NEMAUSA

ADS BibCode:
1983Msngr..32...29G
Author(s)/Affiliation(s):
Gammelgaard, P.; Kristensen, L. K.
AA(Institute of Astronomy, University of Aarhus) AB(Institute of Physics, University of Aarhus)
Abstract:
From the beginning of the discoveries of minor planets in the last century their brightness has been a subject for study. For astronomers mainly interested in variable stars and stellar magnitudes, the minor planets could be a useful tool for transferring the magnitude scale uniformly over the sky. From the observational point of view, minor planets were like variable stars with light variations which could be computed from the distances to the Sun and the Earth. However, at that time the stellar magnitude scale was arbitrary and based only on sUbjective estimates. It was therefore necessary to determine the ratio of light corresponding to a difference of one unit of stellar magnitude. We owe the magnitude scale of our time to N. Pogson, who in his ephemerides of the brightness of 36 minor planets for the year 1857 (1) adopted a light ratio of 2.512 fOr the dlfference of one magnitude.
References:
(1) Argelander, F., Astron. Nachr. 41, (1855) 337.
(2) Pogson, N., Monthly Notices R.A.S. 17 (1856) 12.
(3) Kristensen, L. K., Astron. Astrophys. Suppl. Sero 44, (1981) 375.
(4) Schober, H. J., and Kristensen, L. K., in Sun and Planetary System.
Proc. 01 the 6th European Regional Meeting, W. Fricke and G.
Teleki (editors) (1982).
(5) Chang, Y. C. and Chang, C. S., Acta Astron. Sinica. 11 (1963) 139.
31-33 (PDF)
L. Kohoutek
The Variable Central Star of Planetary Nebula NGC2346

ADS BibCode:
1983Msngr..32...31K
Author(s)/Affiliation(s):
Kohoutek, L.
AA(Hamburger Sternwarte)
Abstract:
NGC 2346, known already to Sir William Herschel, has been classified as a planetary nebula by R. Minkowski (1946) on the basis of its appearance on direct photographs. Morphologically it POssesses a distinct axial symmetry and belongs to the class of bipolar nebulae
References:
Aller, L. H.: 1968, lAU Symp. No. 34 - Planetary Nebulae (eds. O. E.
Osterbroek and C. R. O'Oell), p. 339.
Cohen, M., Barlow, M. J.: 1974, Astrophys. J. 193,401.
Cohen, M., Barlow, M. J.: 1975, Astrophys. Leiters 16,165.
Greenstein, J. L.: 1981, Astrophys. J. 245, 124.
Kohoutek, L.: 1982, IBVS Budapest No. 2113 (see also lAU Cire.
No. 3667).
Kohoutek, L.: 1983, Monthly Notiees (submilted).
Kohoutek, L., Senkbeil, R.: 1973, Mem. Soe. Roy. Sei. Liege, 60 ser.,
t.V,485.
Mendez, R. H., Niemela, V. S.: 1981, Astrophys. J. 250,240.
Mendez, R. H., Gathier, R., Niemela, V. S.: 1982, Astron. Astrophys.
116, L5.
Mendez, R. H., Niemela, V. S., Lee, P.: 1978, Monthly Notiees Roy.
Astron. Soe. 184, 351.
Minkowski, R.: 1946, Publ. Astron. Soe. Paeifie 58, 305.
Sehaefer, B. E.: 1983, IBVS Budapest No. 2281.
33-35 (PDF)
H. Sol
CCD Pictures of Peculiar Galaxies with Jets or Extensions

ADS BibCode:
1983Msngr..32...33S
Author(s)/Affiliation(s):
Sol, H.
AA(Observatoire de Paris-Meudon)
Abstract:
The phenomenon of "jets" seems to be rather universal in astrophysics. The astrophysical jets are seen in different wavelengths, from radio to X-rays. Their more general definitioni is "some emitting material weil collimated along a straight Or curved line". Such features appear on very different scales. Jets having a length of the order of a megaparsec and of a kiloparsec have been detected in different extragalactic systems, respectively aso (e. g. 4C18.68; Gower, Hutchings, Ap. J. 253, L1, 1982) and radio galaxies (e. g. PKS 0521-36; Danziger et al. MNRAS, 188,415, 1979). Jets of a few parsecs have also been suspected in galactic objects as the exotic SS 433, Sco X-1 and R Aquarii. Königl (Ap. J., 261, 115, 1982) even proposed to call jets the asymmetrical outflows which appear in the models of bipolar nebulae, bipolar CO emission lobes and aligned Herbig-Haro objects. Part of the galactic jets could be miniature models of some of the extragalactic ones.
35-37 (PDF)
H. Drechsel et al.
New Optical and X-Ray Observations Yield Progress in Understanding of an Old Nova

ADS BibCode:
1983Msngr..32...35D
Author(s)/Affiliation(s):
Drechsel, H.; Rahe, J.; Wargau, W.
AA(Remeis Observatory Bamberg, Astronomical Institute University Erlangen-Fürth) AB(Remeis Observatory Bamberg, Astronomical Institute University Erlangen-Fürth) AC(Remeis Observatory Bamberg, Astronomical Institute University Erlangen-Fürth)
Abstract:
Nova Aquilae 1918 was the brightest new star that was discovered since Tycho's and Kepler's supernovae in 1572 and 1604, which reached a peak brightness of -4^m and -3^m,respectively. On June 10, 1918, Nova V603 Aquilae went through a sharp maximum of visual brightness -1 ^m.1, followed by a subsequent steep decrease, making it an outstanding example of a classical fast nova. Consequently, it has been the sUbject of many investigations.
37-38 (PDF)
H. Sol
The Optical Jet of R-Aquarii

ADS BibCode:
1983Msngr..32...37S
Author(s)/Affiliation(s):
Sol, H.
AA(Observatoire de Paris-Meudon)
Abstract:
R Aquarii is a stellar system containing a long-period (386 days) Mira variable of spectral type M7e. The presence of an irregularly variable blue continuum and possibly of a several years modulation in the lightcurve suggests that the Mira has a companion, namely a white dwarf with an accretion disk. The most spectacular feature of this symbiotic system is a brigth circumstellar nebula (photographs of which are shown in Sky and Telescope, 64, 141, 1982 by Kaler). This nebula is very likely due to a nova outburst undergone by R Aquarii centuries ago and described in Japanese astronomical records of AD 30 (Kafatos, Michalitsianos, Nature, 298, 540, 1982).
38-38 (PDF)
ESO
Book-Review - Primordial Helium - Proceedings of the ESO Workshop - 1983FEB2-3 - Garching

ADS BibCode:
1983Msngr..32...38S
Author(s)/Affiliation(s):
ESO
AA(ESO)
38-39 (PDF)
ESO
Aluminization of Mirrors

ADS BibCode:
1983Msngr..32R..38.
Author(s)/Affiliation(s):
ESO
AA(ESO)
38-38 (PDF)
ESO
List of Available ESO Publications

ADS BibCode:
1983Msngr..32Q..38.
Author(s)/Affiliation(s):
ESO
AA(ESO)
39-40 (PDF)
ESO
Cometas - distantes y cercanos

ADS BibCode:
1983Msngr..32R..39.
Author(s)/Affiliation(s):
ESO
AA(ESO)
39-39 (PDF)
ESO
Personnel Movements

ADS BibCode:
1983Msngr..32Q..39.
Author(s)/Affiliation(s):
ESO
AA(ESO)