Search Publications
Classification of F ring features observed in Cassini UVIS occultations
Esposito, Larry W.; Sremčević, Miodrag; Meinke, Bonnie K. +1 more
The Cassini Ultraviolet Imaging Spectrograph (UVIS) has detected 27 statistically significant features in 101 occultations by Saturn’s F ring since July 2004. This work nearly doubles the number of features reported by Esposito et al. (Esposito, L.W. et al. [2008]. Icarus 194, 278-289). As the number of statistically significant features has grown…
Pickup protons: Comparisons using the three-dimensional MHD HHMS-PI model and Ulysses SWICS measurements
Sun, Wei; Intriligator, Devrie S.; Detman, Thomas +5 more
We report the first comparisons of pickup proton simulation results with in situ measurements of pickup protons obtained by the SWICS instrument on Ulysses. Simulations were run using the three dimensional (3D) time-dependent Hybrid Heliospheric Modeling System with Pickup Protons (HHMS-PI). HHMS-PI is an MHD solar wind model, expanded to include …
A Spitzer Space Telescope survey of massive young stellar objects in the G333.2-0.4 giant molecular cloud
Lo, Nadia; Burton, Michael G.; Cunningham, Maria R. +3 more
The G333 giant molecular cloud contains a few star clusters and H II regions, plus a number of condensations currently forming stars. We have mapped 13 of these sources with the appearance of young stellar objects (YSOs) with the Spitzer Infrared Spectrograph in the Short-Low, Short-High and Long-High modules (5-36 µm). We use these spectra …
Detection of Accretion X-Rays from QS Vir: Cataclysmic or a Lot of Hot Air?
Drake, Jeremy J.; Steeghs, Danny; Kashyap, Vinay +1 more
An XMM-Newton observation of the nearby "pre-cataclysmic" short-period (P orb = 3.62 hr) binary QS Vir (EC 13471-1258) revealed regular narrow X-ray eclipses when the white dwarf passed behind its M2-4 dwarf companion. The X-ray emission provides a clear signature of mass transfer and accretion onto the white dwarf. The low-resolution X…
Soft Coronal X-Rays from β Pictoris
Schmitt, J. H. M. M.; Robrade, J.; Günther, H. M. +3 more
A-type stars are expected to be X-ray dark, yet weak emission has been detected from several objects in this class. We present new Chandra/HRC-I observations of the A5 V star β Pictoris. It is clearly detected with a flux of (9 ± 2) × 10-4 counts s-1. In comparison with previous data this constrains the emission mechanism and…
New insights on Stephan's Quintet: exploring the shock in three dimensions
Vílchez, J. M.; Petropoulou, V.; López-Martín, L. +2 more
Aims: We study the ionized gas emission from the large scale shock region of Stephan's Quintet (SQ).
Methods: We carried out integral field unit (IFU) optical spectroscopy on three pointings in and near the SQ shock. We used Potsdam MultiAperture Spectrometer (PMAS) on the 3.5 m Calar Alto telescope to obtain measures of emission lines t…
Working models for the gravitational field of Phobos
Shi, Xian; Willner, Konrad; Oberst, Jürgen +2 more
Models for the gravitational field of Mars moon Phobos were developed using the latest shape model and assuming homogeneous density distribution. Three methods were applied in our study. Comparisons were made between these methods and all were shown to yield consistent results. Notably, the most accurate shape model of Phobos to date, complete up …
NGC 2207/IC 2163: A Grazing Encounter with Large-scale Shocks
Brinks, Elias; Struck, Curtis; Elmegreen, Bruce G. +3 more
Radio continuum, Spitzer infrared, optical, and XMM-Newton X-ray and ultraviolet observations (UVW1 and UVM2) are used to study large-scale shock fronts, young star complexes, and the galactic nuclei in the interacting galaxies NGC 2207/IC 2163. There are two types of large-scale shock fronts in this galaxy pair. The large-scale shock front along …
Scattering of the f-mode by Small Magnetic Flux Elements from Observations and Numerical Simulations
Felipe, T.; Braun, D.; Crouch, A. +1 more
The scattering of f-modes by magnetic tubes is analyzed using three-dimensional numerical simulations. An f-mode wave packet is propagated through a solar atmosphere embedded with three different flux tube models that differ in radius and total magnetic flux. A quiet-Sun simulation without a tube present is also performed as a reference. Waves are…
Global Modeling of X-Ray Spectra Produced in O-type Star Winds
Nazé, Y.; Rauw, G.; Hervé, A. +1 more
High-resolution X-ray spectra of O-type stars revealed less wind absorption than expected from smooth winds with conventional mass-loss rates. Various solutions have been proposed, including porous winds, optically thick clumps, or an overall reduction of the mass-loss rates. The latter has a strong impact on the evolution of the star. Our final g…