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Solar Cycle Related Changes at the Base of the Convection Zone
Basu, Sarbani; Baldner, Charles S.
The frequencies of solar oscillations are known to change with solar activity. We use principal component analysis to examine these changes with high precision. In addition to the well-documented changes in solar normal mode oscillations with activity as a function of frequency, which originate in the surface layers of the Sun, we find a small but…
SWAS Observations of Water in Molecular Outflows
Bergin, Edwin A.; Neufeld, David A.; Kaufman, Michael J. +4 more
We present detections of the ground-state 110→ 101 transition of ortho-H2O at 557 GHz in 18 molecular outflows based on data from the Submillimeter Wave Astronomy Satellite (SWAS). These results are combined with ground-based observations of the J = 1-0 transitions of 12CO and 13CO obtained at…
Forced obliquity and moments of inertia of Titan
Nimmo, Francis; Bills, Bruce G.
The obliquity of Titan is small, but certainly non-zero, and may be used to place constraints on Titan's internal structure. The measured gravity coefficients of Titan imply that it is non-hydrostatic and thus the normal Darwin-Radau approach to determining internal structure cannot be applied. However, if the obliquity is assumed to be tidally da…
A global hybrid model for Titan's interaction with the Kronian plasma: Application to the Cassini Ta flyby
Modolo, R.; Chanteur, G. M.
The interaction between the corotating magnetospheric plasma of Saturn and the exosphere of Titan is investigated by means of a three-dimensional and multispecies hybrid simulation model coupling charged and neutral species via three ionizing mechanisms: the absorption of extreme ultraviolet solar photons, the impacts of magnetospheric electrons, …
Adaptive optics imaging and optical spectroscopy of a multiple merger in a luminous infrared galaxy
Östlin, G.; Farrah, D.; Kniazev, A. +16 more
We present near-infrared (NIR) adaptive optics imaging obtained with VLT/NACO and optical spectroscopy from the Southern African Large Telescope of a luminous IR galaxy (LIRG) IRAS 19115-2124. These data are combined with archival Hubble Space Telescope imaging and Spitzer imaging and spectroscopy, allowing us to study this disturbed interacting/m…
Molecular jets driven by high-mass protostars: a detailed study of the IRAS 20126+4104 jet
Eislöffel, J.; Nisini, B.; Giannini, T. +2 more
Context: Protostellar jets from intermediate- and high-mass protostars provide an excellent opportunity to understand the mechanisms responsible for intermediate- and high-mass star-formation. A crucial question is if they are scaled-up versions of their low-mass counterparts. Such high-mass jets are relatively rare and, usually, they are distant …
Titan's Tropical Storms in an Evolving Atmosphere
McKay, Christopher P.; Griffith, Caitlin A.; Ferri, Francesca
The Huygens probe landed in a damp lake bed fed by fluvial channels, indicative of past rainfall. Such washes, interspersed with vast dunes, are typical of Titan's tropical landscape. Yet, Cassini-Huygens measurements reveal a highly stable tropical atmosphere devoid of deep convective storms, and the formation of washes in dune fields is not unde…
Observing the Unobservable? Modeling Coronal Cavity Densities
de Toma, G.; Gibson, S. E.; Fan, Y. +1 more
Prominence cavities in coronal helmet streamers are readily detectable in white-light coronagraph images, yet their interpretation may be complicated by projection effects. In order to determine a cavity's density structure, it is essential to quantify the contribution of noncavity features along the line of sight. We model the coronal cavity as a…
Absorption features in the spectra of X-ray bursting neutron stars
Rauch, T.; Werner, K.; Suleimanov, V.
Context: The discovery of photospheric absorption lines in XMM-Newton spectra of the X-ray bursting neutron star in
Seismic Halos around Active Regions: A Magnetohydrodynamic Theory
Hanasoge, Shravan M.
Comprehending the manner in which magnetic fields affect propagating waves is a first step toward constructing accurate helioseismic models of active region subsurface structure and dynamics. Here we present a numerical method for computing the linear interaction of waves with magnetic fields embedded in a solar-like stratified background. The ide…