Search Publications
Anisotropy of the Taylor scale and the correlation scale in plasma sheet and solar wind magnetic field fluctuations
Kistler, L. M.; Dasso, S.; Mouikis, C. +3 more
Magnetic field data from nine spacecraft in the magnetospheric plasma sheet and the solar wind are employed to determine the correlation scale and the magnetic Taylor microscale from simultaneous multiple-point measurements for multiple intervals with a range of mean magnetic field directions. We have determined that in the solar wind the Taylor s…
Red Supergiants in the Andromeda Galaxy (M31)
Massey, Philip; Clayton, Geoffrey C.; Levesque, Emily M. +5 more
Red supergiants (RSGs) are a short-lived stage in the evolution of moderately massive stars (10-25 M sun), and as such their location in the H-R diagram provides an exacting test of stellar evolutionary models. Since massive star evolution is strongly affected by the amount of mass loss a star suffers, and since the mass-loss rates depe…
Evidence for a Pre-Eruptive Twisted Flux Rope Using the Themis Vector Magnetograph
Aulanier, G.; Canou, A.; Amari, T. +3 more
Although there is evidence that twisted structures form during large-scale eruptive events, it is not yet clear whether these exist in the pre-eruptive phase as twisted flux ropes (TFRs) in equilibrium. This question has become a major issue since several theoretical mechanisms can lead to the formation of TFRs. These models consider either the ev…
High-Speed Transition Region and Coronal Upflows in the Quiet Sun
De Pontieu, Bart; McIntosh, Scott W.
We study the line profiles of a range of transition region (TR) emission lines observed in typical quiet-Sun regions. In magnetic network regions, the Si IV 1402 Å, C IV 1548 Å, N V 1238 Å, O VI 1031 Å, and Ne VIII 770 Å spectral lines show significant asymmetry in the blue wing of the emission line profiles. We interpret these high-velocity upflo…
Heavy negative ions in Titan's ionosphere: Altitude and latitude dependence
Lewis, G. R.; Coates, A. J.; Jones, G. H. +4 more
One of the unexpected results of the Cassini mission was the discovery of negative ions at altitudes between 950 and 1400 km in Titan's ionosphere with masses up to 10,000 amu/q [Coates, A.J., Crary, F.J., Lewis, G.R., Young, D.T., Waite Jr., J.H., Sittler Jr., E.C., 2007. Discovery of heavy negative ions in Titan's ionosphere. Geophys. Res. Lett.…
A Quintet of Black Hole Mass Determinations
Filippenko, Alexei V.; Ho, Luis C.; Gebhardt, Karl +11 more
We report five new measurements of central black hole masses based on Space Telescope Imaging Spectrograph and Wide Field Planetary Camera 2 observations with the Hubble Space Telescope (HST) and on axisymmetric, three-integral, Schwarzschild orbit-library kinematic models. We selected a sample of galaxies within a narrow range in velocity dispers…
The correlated colors of transneptunian binaries
Buie, M. W.; Grundy, W. M.; Noll, K. S. +3 more
We report resolved photometry of the primary and secondary components of 23 transneptunian binaries obtained with the Hubble Space Telescope. V-I colors of the components range from 0.7 to 1.5 with a median uncertainty of 0.06 magnitudes. The colors of the primaries and secondaries are correlated with a Spearman rank correlation probability of 99.…
Cometary dust properties retrieved from polarization observations: Application to C/1995 O1 Hale Bopp and 1P/Halley
Lasue, J.; Levasseur-Regourd, A. C.; Hadamcik, E. +1 more
The analysis of the polarized light scattered by cometary dust particles provides information on the physical properties of the solid component of cometary comae for C/1995 O1 Hale-Bopp and 1P/Halley. A model of light scattering by a size distribution of aggregates of up to 256 submicron-sized grains (spherical or spheroidal) mixed with single sph…
An auroral oval at the footprint of Saturn's kilometric radio sources, colocated with the UV aurorae
Cecconi, B.; Lamy, L.; Nichols, J. D. +3 more
Similarly to other magnetized planets, Saturn displays auroral emissions generated by accelerated electrons gyrating around high-latitude magnetic field lines. They mainly divide in ultraviolet (UV) and infrared (IR) aurorae, excited by electron collisions with the upper atmosphere, and Saturn's kilometric radiation (SKR), radiated from higher alt…
An Empirical Reconstruction of the 2008 April 26 Coronal Mass Ejection
Howard, R. A.; Wood, B. E.
We present a three-dimensional model of the density distribution of a coronal mass ejection (CME) from 2008 April 26. This CME was observed by the two spacecraft composing the Solar Terrestrial Relations Observatory (STEREO), which tracked the CME from near the Sun, into the interplanetary medium (IPM), and all the way to 1 AU. The CME was directe…