Search Publications
Incorporation of a gravity wave momentum deposition parameterization into the Venus Thermosphere General Circulation Model (VTGCM)
Brecht, A. S.; Bougher, S. W.; Rafkin, S. +2 more
The gravity wave-drag parameterization of Alexander and Dunkerton (1999) was implemented into a Venus Thermosphere General Circulation Model (VTGCM) to investigate breaking gravity waves as a source of momentum deposition in Venus' thermosphere. Previously, deceleration of zonal jets on the morning and evening terminators in models was accomplishe…
Plasma Heating in a Post Eruption Current Sheet: A Case Study Based on Ultraviolet, Soft, and Hard X-Ray Data
Krucker, Säm; Bemporad, A.; Susino, R.
Off-limb observations of the solar corona after coronal mass ejections (CMEs) often show strong, compact, and persistent UV sources behind the eruption. They are primarily observed by the SOHO/UVCS instrument in the "hot" [Fe XVIII] λ974 line and are usually interpreted as a signature of plasma heating due to magnetic reconnection in the post-CME …
Comparison between hybrid and fully kinetic models of asymmetric magnetic reconnection: Coplanar and guide field configurations
Hesse, Michael; Aunai, Nicolas; Zenitani, Seiji +4 more
Magnetic reconnection occurring in collisionless environments is a multi-scale process involving both ion and electron kinetic processes. Because of their small mass, the electron scales are difficult to resolve in numerical and satellite data, it is therefore critical to know whether the overall evolution of the reconnection process is influenced…
Modeling of meteoroid streams: The velocity of ejection of meteoroids from comets (a review)
Ryabova, G. O.
An analytical review of the models of ejection of meteoroids from cometary nuclei is presented. Different formulas for the ejection velocity of meteoroids and the corresponding parameters are discussed and compared with the use of comet Halley and the Geminids meteoroid stream as examples. The ejection velocities obtained from observations of the …
A Comparison of Solar Cycle Variations in the Equatorial Rotation Rates of the Sun's Subsurface, Surface, Corona, and Sunspot Groups
Javaraiah, J.
Using the Solar Optical Observing Network (SOON) sunspot-group data for the period 1985 - 2010, the variations in the annual mean equatorial-rotation rates of the sunspot groups are determined and compared with the known variations in the solar equatorial-rotation rates determined from the following data: i) the plasma rotation rates at 0.94R…
Flexion measurement in simulations of Hubble Space Telescope data
Massey, Richard; Rhodes, Jason; Heymans, Catherine +5 more
We present a simulation analysis of weak gravitational lensing flexion and shear measurement using shapelet decomposition, and identify differences between flexion and shear measurement noise in deep survey data. Taking models of galaxies from the Hubble Space Telescope Ultra Deep Field (HUDF) and applying a correction for the HUDF point spread fu…
The Metallicity Dependence of the Cepheid P - L Relation in M101
Madore, Barry F.; Freedman, Wendy L.; Mager, Violet A.
The impact of metallicity on the Cepheid period-luminosity (P - L) relation is investigated using Hubble Space Telescope Advanced Camera for Surveys V and I images of M101. Variations in the reddening-free Wesenheit parameter (W), which is employed as a proxy for luminosity, are examined as a function of the radial distance from the center of M101…
New nitric oxide (NO) nightglow measurements with SPICAM/MEx as a tracer of Mars upper atmosphere circulation and comparison with LMD-MGCM model prediction: Evidence for asymmetric hemispheres
Montmessin, Franck; Bertaux, Jean-Loup; González-Galindo, Francisco +3 more
We report observations of NO nightglow with the Spectroscopy for the Investigation of the Characteristics of the Atmosphere of Mars (SPICAM) experiment on board the Mars Express (MEx) spacecraft. NO molecules emit an ultraviolet photon when N and O atoms (produced at high altitude in the thermosphere) recombine. Therefore, this emission is a trace…
Active asteroid belt causes the UXOR phenomenon in RZ Piscium
Grinin, V. P.; Müller, A.; de Wit, W. J. +3 more
We report the discovery of mid-infrared excess emission in the young object RZ Psc. The excess constitutes ~8% of its Lbol and is well fit by a single 500 K blackbody, implying a dust-free region within ~0.7 AU for optically thick dust. The object displays dust obscuration events (UXOR behaviour) on a time scale that suggests dusty mate…
First identification and absolute magnitudes of the red clump stars in the Solar neighbourhood for WISE
Bilir, S.; Ak, T.; Karaali, S. +4 more
We present the first determination of absolute magnitudes for the red clump (RC) stars with the Wide-field Infrared Survey Explorer (WISE). We used recently reduced parallaxes taken from the Hipparcos catalogue and identified 3889 RC stars with the WISE photometry in the Solar neighbourhood. Mode values estimated from the distributions of absolute…