11 research outputs found
A Giant Planet Around a Metal-poor Star of Extragalactic Origin
Stars in their late stage of evolution, such as Horizontal Branch stars, are
still largely unexplored for planets. We report the detection of a planetary
companion around HIP 13044, a very metal-poor star on the red Horizontal
Branch, based on radial velocity observations with a high-resolution
spectrograph at the 2.2-m MPG/ESO telescope. The star's periodic radial
velocity variation of P=16.2 days caused by the planet can be distinguished
from the periods of the stellar activity indicators. The minimum mass of the
planet is 1.25 Jupiter masses and its orbital semi-major axis 0.116 AU. Because
HIP 13044 belongs to a group of stars that have been accreted from a disrupted
satellite galaxy of the Milky Way, the planet most likely has an extragalactic
origin.Comment: 32 pages, 9 Figure
Operations and logistics tasks in the COLUMBUS development program
With 9 figs.Available from TIB Hannover: RO 7420(166-91PUB) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman
Design, development and verification of the EURECA A orbit transfer assembly (OTA)
SIGLECopy held by FIZ Karlsruhe; available from UB/TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman
Design of spacecraft verified by test in a modular form
SIGLECopy held by FIZ Karlsruhe; available from UB/TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman
The ultra heavy cosmic ray data from the DUBLIN-ESTEC experiment on LDEF satellite and a halo diffusion model for cosmic rays Invited paper presented at COSPAR, July 1994
The preliminary results for the ultra heavy cosmic ray component measured by the DUBLIN-ESTEC experiment on the LDEF satellite has given 'next generation' quality data, which will provide quantitative implications regarding the nature of cosmic ray sources, for which no entirely satisfactory answer has yet been given. These data are compared with a new source and propagation model for cosmic rays - the halo diffusion model. The halo diffusion model assumes the cosmic ray sources in the inner Galaxy and the propagation of cosmic rays from this region via the galactic halo to the Sun. Nearly all processes for energy or particle losses are considered. A primary result is the good agreement between the observed and calculated abundances of ultra heavy cosmic rays. Moreover the observed galactic cosmic ray gradient can be explained by means of this realistic model and the calculated antiproton flux is in the order of the measured one at the Earth. (orig.)Available from TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman
Untersuchungen zu einem offset-Doppelgitterreflektor fuer Mehrstrahlantennen bei Nachrichtensatelliten
Also published in: Kleinheubacher Berichte, v. 28, 1985Copy held by FIZ Karlsruhe; available from UB/TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman
Ion beam driven electrostatic shocks
SIGLECopy held by FIZ Karlsruhe; available from UB/TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman
The UV/X-ray emission of the symbiotic star AG draconis during quiescence and the 1994/1995 outbursts
We present the results of an extensive campaign of coordinated X-ray (ROSAT) and UV (IUE) observations of the symbiotic star AG Dra during a long period of quiescence followed recently by a remarkable phase of activity characterized by two optical outbursts. The major optical outburst in June 1994 and the secondary outburst in July 1995 were covered by a number of target of opportunity observations (TOO) with both satellites. Optical photometry is used to establish the state of evolution along the outburst. Our outburst observations are supplemented by a substantial number of X-ray observations of AG Dra during its quiescent phase between 1990-1993. Near-simultaneous IUE observations at the end of 1992 are used to derive the spectral energy distribution from the optical to the X-ray range. The X-ray flux remained constant over this three year quiescent phase. The hot component (i.e. X-ray emitting compact object) turns out to be very luminous: a blackbody fit to the X-ray data in quiescence with an absorbing column equal to the total galactic N_H in this direction gives (9.5#+-#1.5) x 10"3"6 (D/2.5 kpc)"2 erg/s. This suggests that the compact object is burning hydrogen-rich matter on its surface even in the quiescent (as defined optically) state at a rate of (3.2#+-#0.5) x 10"-"8 (D/2.5 kpc)"2 M_sun/yr. Assuming a steady state, i.e. burning at precisely the accretion supply rate, this high rates suggests a Roche lobe filling cool companion though Bondi-Hoyle accretion from the companion wind cannot be excluded. With ROSAT observations we have discovered a remarkable decrease of the X-ray flux during both optical maxima, followed by a gradual recovering to the preoutburst flux. In the UV these events were characterized by a large increase of the emission line and continuum fluxes, comparable to the behaviour of AG Dra during the 1980-81 active phase. The anticorrelation of X-ray/UV flux and optical brightness evolution is very likely due to a temperature decrease of the hot component. Such a temperature decrease could be the result of an increased mass transfer to the burning compact object, causing it to slowly expand to about twice its original size during each optical outburst. (orig.)SIGLEAvailable from TIB Hannover: RN 9303(379) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman
IRAS04496-6958: A luminous carbon star with silicate dust in the large Magellanic Cloud
SIGLEAvailable from: http://www.mpa-garching.mpg.de / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman