Search results for "Jupiter"
showing 10 items of 31 documents
Zvaigžņotā Debess: 2004/05, Ziema
2004
Contents: Ņ.Ozoliņa. Earthquakes in Latvia ; I.Daube. Space Craft “Ranger-7” ; M. Gailis. Moon Investigation in Riga ; J.Tambergs. Problems of Dialogue between Quantum Mechanics and Theology (concluded) ; Z Alksne, A.Alksnis. Ultra-Cool Dwarf Pair Weighed ; A.Balklavs. Successful Hunt of Protostars ; A.Balklavs. Silhouette of a Black Hole ; A.Balklavs. A Distant Giant Quasar ; A.Balklavs. Cosmic Objects in Captivating Photos – 3 ; J.Freimanis. Extragalactic Planetary Nebulae ; J.Jaunbergs. Cassini Enters the Saturnian System ; D.Krieviņš. Space Launchers of Early XXI Century. The Commonwealth of Independent States (CIS) ; J.Bārzdiņš. Professor Rusins-Martins Freivalds on the Path of Science…
High-Energy Electron-Induced SEUs and Jovian Environment Impact
2017
We present experimental evidence of electron-induced upsets in a reference European Space Agency (ESA) single event upset (SEU) monitor, induced by a 200-MeV electron beam at the Very energetic Electronic facility for Space Planetary Exploration in harsh Radiation environments facility at CERN. Comparison of experimental cross sections and simulated cross sections is shown and the differences are analyzed. Possible secondary contributions to the upset rate by neutrons, flash effects, and cumulative dose effects are discussed, showing that electronuclear reactions are the expected SEU mechanism. The ESA Jupiter Icy Moons Explorer mission, to be launched in 2022, presents a challenging radiat…
Electron-Induced Upsets and Stuck Bits in SDRAMs in the Jovian Environment
2021
This study investigates the response of synchronous dynamic random access memories to energetic electrons and especially the possibility of electrons to cause stuck bits in these memories. Three different memories with different node sizes (63, 72, and 110 nm) were tested. Electrons with energies between 6 and 200 MeV were used at RADiation Effects Facility (RADEF) in Jyvaskyla, Finland, and at Very energetic Electron facility for Space Planetary Exploration missions in harsh Radiative environments (VESPER) in The European Organization for Nuclear Research (CERN), Switzerland. Photon irradiation was also performed in Jyvaskyla. In these irradiation tests, stuck bits originating from electro…
HST observation of the inner coma of 2060 chiron
1995
Abstract The analysis of persistent comae of very large and distant comets allows us to infer the poorly known physical properties of dust and icy grains produced beyond Jupiter. Chiron is particularly interesting because Fulle ( Astron. Astrophys. 282 , 980–988; 1994) has shown that the strong asymmetricity of its coma (West, Astron. Astrophys. 241 , 635–645 1991) allows us to infer rotational properties of Chiron's nucleus. In this paper we report the observation of the asymmetric inner coma of Chiron from the analysis of 44 images of Chiron and eight images of a standard star available from the HST archive. The images were taken during February/March 1993, when Ch iron was 9.3 AU from th…
Multi-band high resolution spectroscopy rules out the hot Jupiter BD+20 1790b - First data from the GIARPS Commissioning
2018
Context. Stellar activity is currently challenging the detection of young planets via the radial velocity (RV) technique. Aims. We attempt to definitively discriminate the nature of the RV variations for the young active K5 star BD+20 1790, for which visible (VIS) RV measurements show divergent results on the existence of a substellar companion. Methods. We compare VIS data with high precision RVs in the near infrared (NIR) range by using the GIANO - B and IGRINS spectrographs. In addition, we present for the first time simultaneous VIS-NIR observations obtained with GIARPS (GIANO - B and HARPS - N) at Telescopio Nazionale Galileo (TNG). Orbital RVs are achromatic, so the RV amplitude does …
Analysis of the orbit of the Centaur asteroid 2009 HW77
2011
We present the time evolution of orbital elements of the Centaur asteroid 2009 HW77, discovered by KC and IE, forwards and backwards in time over a 10-Myr period. The dynamical behaviour is analysed using three software packages: the OrbFit, the swift and the Mercury integrators. Changes in the orbital elements of 2009 HW77 clones are calculated using the classification of Horner et al. It is shown that close approaches to the giant planets significantly change the asteroid orbit. Our computations made with the swift software and with the Mercury software give similar results. The half-life is about 5 Myr in both the forward and backward integrations. Moreover, our computations suggest that…
The effect of ISM absorption on stellar activity measurements and its relevance for exoplanet studies
2017
Past UV and optical observations of stars hosting hot Jupiters have shown that some of these stars present an anomalously low chromospheric activity, significantly below the basal level. For WASP-13, observations have shown that the apparent lack of activity is possibly caused by absorption from the intervening ISM. Inspired by this result, we study the effect of ISM absorption on activity measurements (S and logR'$_{\rm HK}$ indices) for main-sequence late-type stars. To this end, we employ synthetic stellar photospheric spectra combined with varying amounts of chromospheric emission and ISM absorption. We present the effect of ISM absorption on activity measurements by varying several ins…
Zvaigžņotā Debess: 2005, Rudens
2005
Latvijas Zinātnes padome, Latvijas Universitāte
Zvaigžņotā Debess: 2004, Rudens (185)
2004
Contents: L.Kondraševa and I.Zimina. New Riga Planetarium ; I.Rabinovičs. Remembering Fricis Blumbahs ; N.Cimahoviča. 50 cm Reflector Constructed in Riga ; J.Tambergs. Problems of Dialogue between Quantum Mechanics and Theology. A.Alksnis, Z.Alksne. The Sloan Great Wall ; A.Balklavs. Radio Galaxy – Emitter of Very High Energy Gamma-Rays ; A.Balklavs. Cosmic Objects in Photos – 2 ; A.Balklavs. New Assessments of Fine-Structure Constant Variability ; N.Cimahoviča. Dark Electric Matter Objects Around Us ; A.Balklavs. New Data on the Solar Granulation ; J.Jaunbergs. The Sinking Cliffs on Io ; D.Krieviņš. Space Launchers of Early XXI Century ; M.Sudārs. SpaceShipOne Closest to X-Prize ; J.Harja.…
Les bronzes figurés antiques du Musée de Mâcon (Saône-et-Loire, F)
2011
In the course of its history, the Musee des Ursulines, at Macon, collected about 10 bronze figurines, some of them found as early as the mid-17th c. This article describes this largely unpublished collection and its scientific implications. Among the new data appears a votive bronze statuette, of italic type, found locally and datable to the Vth-IVth c. BC.