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Fred Goesmann Helmut Rosenbauer Reinhard Roll Cyril Szopa Francois Raulin Robert Sternberg Guy Israel Uwe Meierhenrich Wolfram Thiemann Guillermo Munoz-Caro 《Space Science Reviews》2007,128(1-4):257-280
Comets are thought to preserve the most pristine material currently present in the solar system, as they are formed by agglomeration
of dust particles in the solar nebula, far from the Sun, and their interiors have remained cold. By approaching the Sun, volatile
components and dust particles are released forming the cometary coma. During the phase of Heavy Bombardment, 3.8--4 billion
years ago, cometary matter was delivered to the Early Earth. Precise knowledge on the physico-chemical composition of comets
is crucial to understand the formation of the Solar System, the evolution of Earth and particularly the starting conditions
for the origin of life on Earth. Here, we report on the COSAC instrument, part of the ESA cometary mission Rosetta, which
is designed to characterize, identify, and quantify volatile cometary compounds, including larger organic molecules, by in
situ measurements of surface and subsurface cometary samples. The technical concept of a multi-column enantio-selective gas
chromatograph (GC) coupled to a linear reflectron time-of-flight mass-spectrometer instrument is presented together with its
realisation under the scientific guidance of the Max-Planck-Institute for Solar System Research in Katlenburg-Lindau, Germany.
The instrument's technical data are given; first measurements making use of standard samples are presented. The cometary science
community is looking forward to receive fascinating data from COSAC cometary in situ measurements in 2014. 相似文献
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Jelena Kovačević Luka Č. Popović Wolfram Kollatschny 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2014
Here we present a new method for subtracting the Balmer pseudocontinuum in the UV part of type 1 AGN spectra. We calculate the intensity of the Balmer pseudocontinuum using the prominent Balmer lines in AGN spectra. We apply the model on a sample of 293 type 1 AGNs from SDSS database, and found that our model of Balmer pseudocontinuum + power law continuum very well fits the majority of AGN spectra from the sample, while in ∼15% of AGNs, the model fits reasonable the UV continuum, but a discrepancy between the observed and fitted spectra is noted. Some of the possible reasons for the discrepancy may be a different value for the optical depth in these spectra than used in our model or the influence of the intrinsic reddening. 相似文献
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