Search Publications
X-ray emission from classical T Tauri stars: accretion shocks and coronae?
Liefke, C.; Schmitt, J. H. M. M.; Robrade, J. +1 more
Context: Classical T Tauri stars (CTTS) are surrounded by actively accreting disks. According to current models material falls along the magnetic field lines from the disk with more or less free-fall velocity onto the star, where the plasma heats up and generates X-rays.
Aims: We want to quantitatively explain the observed high energy emission…
X-Ray Spectral Variation of η Carinae through the 2003 X-Ray Minimum
Hamaguchi, Kenji; Corcoran, Michael F.; Hillier, D. John +7 more
We report the results of an observing campaign on η Car around the 2003 X-ray minimum, mainly using the XMM-Newton observatory. These are the first spatially resolved X-ray monitoring observations of the stellar X-ray spectrum during the minimum. The hard X-ray emission, associated with the wind-wind collision (WWC) in the binary system, varied st…
Cosac, The Cometary Sampling and Composition Experiment on Philae
Szopa, Cyril; Roll, Reinhard; Goesmann, Fred +7 more
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…
Strong rapid dipolarizations in Saturn's magnetotail: In situ evidence of reconnection
Russell, C. T.; Dougherty, M. K.; Jackman, C. M. +3 more
The oppositely directed magnetic field in the kronian magnetic tail is expected eventually to reconnect across the current sheet, allowing plasma to escape in an anti-solar direction down the tail. This reconnection process accelerates ions and electrons both toward and away from the planet, allowing the magnetotail to relax to a more dipolar conf…
Understanding coronal heating and solar wind acceleration: Case for in situ near-Sun measurements
Sittler, E. C.; McComas, D. J.; Bothmer, V. +17 more
The solar wind has been measured directly from 0.3 AU outward, and the Sun's atmosphere has been imaged from the photosphere out through the corona. These observations have significantly advanced our understanding of the influence of the Sun's varying magnetic field on the structure and dynamics of the corona and the solar wind. However, how the c…
Lineated valley fill and lobate debris apron stratigraphy in Nilosyrtis Mensae, Mars: Evidence for phases of glacial modification of the dichotomy boundary
Head, James W.; Levy, Joseph S.; Marchant, David R.
The Nilosyrtis Mensae region is important among dichotomy boundary fretted terrain outcrops, as it provides evidence of overprinting of ancient landscapes by a suite of glacial features, providing a composite view of the variety of midlatitude glacial modification processes that can occur during recent Martian ice ages. On the basis of a series of…
γ2 Velorum: orbital solution and fundamental parameter determination with SUSI
Tuthill, P. G.; Davis, J.; Tango, W. J. +1 more
The first complete orbital solution for the double-lined spectroscopic binary system γ2 Velorum, obtained from measurements with the Sydney University Stellar Interferometer (SUSI), is presented. This system contains the closest example of a Wolf-Rayet star and the promise of full characterization of the basic properties of this exotic …
Where the Blue Stragglers Roam: Searching for a Link between Formation and Environment
Sills, Alison; Knigge, Christian; Leigh, Nathan
The formation of blue stragglers is still not completely understood, particularly the relationship between formation environment and mechanism. We use a large, homogeneous sample of blue stragglers in the cores of 57 globular clusters to investigate the relationships between blue straggler populations and their environments. We use a consistent de…
The Stellar Population of Lyα-emitting Galaxies at z ~ 5.7
Cowie, Lennox L.; Huang, Jia-Sheng; Hu, Esther M. +3 more
We present a study of three Lyα-emitting galaxies (LAEs), selected via a narrowband survey in the GOODS northern field and spectroscopically confirmed to have redshifts of z~5.65. Using HST ACS and Spitzer IRAC data, we constrain the rest-frame UV-to-optical spectral energy distributions (SEDs) of the galaxies. Fitting stellar population synthesis…
Lightning on Venus inferred from whistler-mode waves in the ionosphere
Russell, C. T.; Wei, H. Y.; Zhang, T. L. +3 more
The occurrence of lightning in a planetary atmosphere enables chemical processes to take place that would not occur under standard temperatures and pressures. Although much evidence has been reported for lightning on Venus, some searches have been negative and the existence of lightning has remained controversial. A definitive detection would be t…