Communiqués de presse

7 mars 1996: A bright 'new' star was discovered by Japanese amateur astronomer Yukio Sakurai in late February 1996. It is located in the star-rich, southern constellation of Sagittarius (The Archer) and qualifies to join an extremely select class of stars. In fact, we know only one additional object of this type and the remains of two - possibly three - others. Compared to the 6000 stars in the sky seen with the naked eye, the several millions so far catalogued, and the billions of stars photographed, it is a very special class indeed. Nevertheless, Sakurai's star holds unique information about a dramatic evolutionary state, which all stars must to pass through whose masses are more than a few times that of the Sun, but still too small to produce a supernova explosion. This happens just before they end their active life and cool down into visual oblivion.

6 mars 1996: With the help of a new and more sensitive receiver, recently installed on the 15-metre Swedish-ESO Submillimetre Telescope (SEST) at the European Southern Observatory on the La Silla mountain in Chile, a team of European astronomers [1] has succeeded in discovering the first extra-galactic silicon-monoxide (SiO) maser . It is located in the atmosphere of the largest known star in the Large Magellanic Cloud, a satellite galaxy to the Milky Way. This observational feat now opens new, exciting possibilities for the study of individual stars in other galaxies in the Local Group. The continued search for extra-galactic SiO masers is a joint project of European and Australian astronomers, to be carried on with even more advanced instruments that will become available in the near future.

4 mars 1996: This is the most detailed image so far obtained of the complex tail system of Comet Hyakutake. It was obtained with the ESO 1-m Schmidt telescope at La Silla on February 28.36 UT under good observing conditions by ESO night assistant Oscar Pizarro. The exposure lasted 60 min and was made on sensitized Kodak Pan 4415 film behind a GG385 filtre. This emulsion/filtre combination allows to record a broad spectral interval (3900-7000 A) whereby faint structures are better seen. However, detailed spectral information, by which the emitters may be identified, is lost for the same reason.

4 mars 1996: Spectra of Comet Hyakutake were obtained at the ESO La Silla Observatory on February 29.3 UT by Klaus Simon (Institute for Astronomy and Astrophysics, University of Munich, Germany) and Chris Lidman (ESO-Chile). They used the Danish 1.54-m telescope with the multi-mode DFOSC instrument and a large CCD. The slit was centred on the brightest part of the cometary coma. The frames were reduced by S. Benetti (ESO-Chile).

2 mars 1996: These false-colour images are reproductions from a short-exposure CCD frame, obtained with the Danish 1.54-metre telescope and the DFOSC instrument with a 2052 x 2052 pix Loral/Lesser CCD. They show the innermost coma of Comet Hyakutake and the pronounced asymmetry of the dust distribution around the nucleus.

21 février 1996: During the first weeks following its discovery on January 31, 1996, Comet C/1996 B2 (Hyakutake) has gradually brightened from magnitude 11-12 to 8. As it moves nearer to the Sun and is headed for a close approach to the Earth in late March 1996, the observers continue to describe it as diffuse, with a central condensation, but no typical comet tails were seen so far.

16 février 1996: In the early morning of January 31, 1996, Japanese amateur astronomer Yuji Hyakutake made his second comet discovery within five weeks. He found the new comet near the border between the southern constellations of Hydra (The Water-Snake) and Libra (The Scales), amazingly just three degrees from the position where he detected another comet on December 26, 1995.

16 février 1996: This false-colour photo demonstrates the asymmetry, now apparent in the coma of Comet C/1996 B2 (Hyakutake). This comet will make a close approach to the Earth (15 million kilometres) on March 25, 1996.

11 février 1996: This diagramme shows the first spectrum obtained of comet C/1996 B2 (Hyakutake), which is expected to pass near the Earth in late March 1996. It was taken by Tomaz Zwitter, visiting astronomer at the ESO La Silla Observatory from the University of Ljubljana, Slovenia. It has been flux- [(erg/s/cm2/A) within 2x14 arcsecond slit centered on comet] and wavelength- [Angstrom] calibrated.

11 février 1996: These false-colour photos show the first images of comet C/1996 B2 (Hyakutake), obtained with the DFOSC instrument at the Danish 1.54-metre telescope at the ESO La Silla Observatory. This comet is expected to become quite bright when it passes near the Earth in late March 1996.

9 février 1996: This false-colour image of Comet Hale-Bopp is the first to be obtained with a major astronomical telescope after the recent conjunction with the Sun. At the time of this observation, the comet was located in the southern constellation of Sagittarius, and only 32 degrees from the Sun.

9 février 1996: This new image obtained with ESO's New Technology Telescope (NTT) shows the split nucleus of comet Schwassmann-Wachmann 3.

9 février 1996: In the context of a comprehensive Key-Programme , carried out with telescopes at the ESO La Silla Observatory, a team of European astronomers [1]. has recently obtained radial velocities for more than 5600 galaxies in about 100 rich clusters of galaxies. With this programme the amount of information about the motions of galaxies (the kinematical data) in such clusters has almost been doubled. This has allowed the team to study the distribution of the cluster masses, and also the dynamical state of clusters in new and interesting ways.

9 février 1996: One more cosmic mirage has been found with the ESO 3.5-metre New Technology Telescope (NTT). It consists of two images of the same quasar, seen very close to each other in the southern constellation of Hydra (The Water-Snake).

2 février 1996: This photo was obtained on 15 January 1996 and shows the progression of the work on the enclosure for VLT Unit Telescope no. 1 on Cerro Paranal.

2 février 1996: This aerial photo was obtained on 16 January 1996 and shows the progression of the work at the VLT Observatory on Cerro Paranal in the Chilean Atacama desert, about 130 km south of the town of Antofagasta.

19 janvier 1996: How many moons has Saturn, the second-largest planet in the solar system? Until recently, the best answer was eighteen, ranging from innermost Pan that circles the planet 75,000 km above the cloud tops in a little less than 14 hours, to distant Phoebe, 13 million km away in a reverse ('retrograde') 550-day orbit [1]. Now the situation is less clear.

12 janvier 1996: For some time, the astronomical community in Australia has expressed interest in closer ties to ESO. One of the main reasons is the construction of the ESO Very Large Telescope (VLT), of which the first 8.2 m unit telescope is scheduled for completion less than 2 years from now.

5 janvier 1996: A few months ago, Periodic Comet Schwassmann-Wachmann 3 underwent a dramatic and completely unexpected, thousand-fold brightening. At that time, the cause for this interesting event was unknown. However, observations with the two largest ESO telescopes have now shown that the "dirty snowball" nucleus of this comet has recently split into at least four individual pieces. There is little doubt that the outburst and the splitting event(s) are closely related and that the greatly increased dust and gas production is due to "fresh" material of the icy cometary nucleus becoming exposed to the surrounding space for the first time.

5 décembre 1995: As the ESO Very Large Telescope (VLT) rapidly takes on shape, Europe has just come one step closer to the realisation of its 556 million DEM astronomical showcase project.