Sven Geier

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[1] The NASA Discovery Moon Mineralogy Mapper imaging spectrometer was selected to pursue a wide range of science objectives requiring measurement of composition at fine spatial scales over the full lunar surface. To pursue these objectives, a broad spectral range imaging spectrometer with high uniformity and high signal‐to‐noise ratio capable of measuring(More)
– 2 – Hot subdwarf B stars (sdBs) are extreme horizontal branch stars believed to originate from close binary evolution. Indeed about half of the known sdB stars are found in close binaries with periods ranging from a few hours to a few days. The enormous mass loss required to remove the hydrogen envelope of the red-giant progenitor almost entirely can be(More)
The Moon Mineralogy Mapper (M3) was selected as a NASA Discovery Mission of Opportunity in February 2005. The M3 instrument is a high uniformity and high precsion imaging spectrometer of the pushbroom type. M3 measures spectra as images in the solar dominated portion of the electromagnetic spectrum. The basis for the use of imaging spectroscopy for mapping(More)
Introduction: The Moon Mineralogy Mapper (M3) is a high uniformity and high signal-to-noise ratio imaging spectrometer of the pushbroom type [1,2,3] and a NASA Discovery Mission of Opportunity. M3 measures images of 600 cross-track spatial elements and 260 contiguous spectral channels nominally from 430 to 3000 nm at 10 nm sampling. The basis for the use of(More)
Accurate characterization of surface reflection is essential for retrieval of aerosols using downward-looking remote sensors. In this paper, observations from the Ground-based Multiangle SpectroPolarimetric Imager (GroundMSPI) are used to evaluate a surface polarized bidirectional reflectance distribution function (PBRDF) model. GroundMSPI is an eight-band(More)
Hypervelocity stars (HVSs) travel with velocities so high that they exceed the escape velocity of the Galaxy. Several acceleration mechanisms have been discussed. Only one HVS (US 708, HVS 2) is a compact helium star. Here we present a spectroscopic and kinematic analysis of US 708. Traveling with a velocity of ~1200 kilometers per second, it is the fastest(More)
Context. High-velocity stars in the Galactic halo, e.g. the so-called hyper-velocity stars (HVS), are important tracers of the properties of the dark matter halo, in particular its mass. Aims. A search for the fastest stars among hot subdwarfs (sdB) in the halo is carried out to identify HVS, unbound to the Galaxy, and bound population II stars in order to(More)