Search Publications
Common Proper Motion Search for Faint Companions Around Early-Type Field Stars – Progress Report
Huélamo, N.; Foellmi, C.; Chauvin, G. +5 more
The multiplicity of early-type stars is still not well established. The derived binary fraction is different for individual star forming regions, suggesting a connection with the age and the environment conditions. The few studies that have investigated this connection do not provide conclusive results. To fill in this gap, we started the first de…
Search for causes of the low epithermal neutron flux anomaly in the Arabia Terra region (Mars)
Head, J. W.; Neukum, G.; Werner, S. +8 more
A geologic analysis of 274 images acquired by the high-resolution MOC camera onboard the Mars Global Surveyor spacecraft within the Arabia Terra low neutron flux anomaly (which is indicative of an anomalously high abundance of hydrogen: up to 16 wt % of the equivalent amount of water) was performed. Correlation between the enhanced abundance of eq…
A criterion to discriminate between solar and cosmic ray forcing of the terrestrial climate
Fichtner, H.; Scherer, K.; Heber, B.
There is increasing evidence that there exist interstellar-terrestrial relations and that the heliosphere's effectivity to serve as a protecting shield for the Earth, specifically against cosmic rays, is varying in time. Nonetheless, a debate is going on whether, amongst other drivers, the Sun or the cosmic rays are influencing the terrestrial cli…
A reconstruction method for the reconnection rate applied to Cluster magnetotail measurements
Penz, T.; Kubyshkin, I. V.; Nakamura, R. +6 more
We apply a theoretical model to describe the behavior of nightside flux transfer events (NFTEs) measured by Cluster satellites in the Earth magnetotail. Based on the Cagniard deHoop method we calculate the magnetic field and plasma flow time series observed by a satellite. Our aim is to solve an inverse problem to obtain the reconnection rate from…
Structure and Evolution of White Dwarfs and their Interaction with the Local Interstellar Medium
Werner, K.; Barstow, M. A.
The development of far-UV astronomy has been particularly important for the study of hot white dwarf stars. A significant fraction of their emergent flux appears in the far-UV and traces of elements heavier than hydrogen or helium are, in general, only detected in this waveband or at shorter wavelengths that are also only accessible from space. Al…
Huygens entry emission: Observation campaign, results, and lessons learned
de Pater, Imke; Lorenz, Ralph D.; Lemmon, Mark T. +8 more
An attempt was made to observe from Earth the emission from the shock layer and ``meteor trail'' formed during the Huygens probe's hypersonic entry into Titan's atmosphere. Although many observations were wiped out by weather or in-orbit failure, two observations constrain the emission from the entry. Several important lessons for future observati…
Discovery of an Eclipsing X-Ray Binary with a 32.69 hr Period in M101: An Analog of Her X-1 or LMC X-4?
Liu, Jifeng; Di Stefano, Rosanne; Kuntz, Kip +3 more
We report the discovery of an eclipsing X-ray binary in M101, the first such system to be discovered outside the Local Group. Based on a sequence of 25 Chandra observations that sample a wide range of orbital phases, we find a period of 32.688+/-0.002 hr, which we interpret as an orbital period. The folded light curve exhibits an eclipse lasting a…
Radial mean velocity in the solar neighbourhood
Cubarsi, R.; Alcobé, S.
A large sample with the full space motions drawn from the Hipparcos Catalogue allows us to select some nested subsamples containing an increasing number of thick disk stars. Segregated thick disk populations show a progressive decreasing vertex deviation according to a trend of axial symmetry, as well as an increasing velocity dispersion and mean …
Discrimination between Jovian radio emissions and Saturn electrostatic discharges
Gurnett, D. A.; Kurth, W. S.; Fischer, G. +5 more
Short vertical streaks in the dynamic spectrum of the Cassini/RPWS (Radio and Plasma Wave Science) receiver in the frequency range of a few MHz can be due to Jovian radio emissions or SEDs (Saturn electrostatic discharges). Although Jupiter is increasingly far from Cassini, the peaks of decametric Jovian arcs can still be detected a few dB above t…
High-resolution X-ray spectra of solar flares
Doschek, G. A.
I discuss high-resolution solar flare soft X-ray spectra and also comment on some recent results from extreme ultraviolet (EUV) spectroscopy. Spectra of solar flares at these wavelengths have been recorded since the late 1960s, beginning primarily with the NASA Orbiting Solar Observatory (OSO) series of spacecraft. Knowledge of EUV flare spectra t…