Search Publications
Electron acoustic solitons in the presence of an electron beam and superthermal electrons
Lakhina, G. S.; Singh, S. V.; Bharuthram, R. +1 more
Arbitrary amplitude electron acoustic solitons are studied in an unmagnetized plasma having cold electrons and ions, superthermal hot electrons and an electron beam. Using the Sagdeev pseudo potential method, theoretical analysis is carried out by assuming superthermal hot electrons having kappa distribution. The results show that inclusion of an …
Evolution of the equatorial oscillation in Saturn's stratosphere between 2005 and 2010 from Cassini/CIRS limb data analysis
Flasar, F. M.; Bézard, B.; Fouchet, T. +2 more
We present an analysis of thermal infrared spectra acquired in limb viewing geometry by Cassini/CIRS in February 2010. We retrieve vertical profiles of Saturn's stratospheric temperature from 20 hPa to 10-2 hPa, at 9 latitudes between 20°N and 20°S. Using the gradient thermal wind equation, we derive a map of the zonal wind field. Both …
The expansion proper motions of the planetary nebula NGC 6302 from Hubble Space Telescope imaging
Walsh, J. R.; Zijlstra, A. A.; Szyszka, C.
Planetary nebulae expand on time-scales of 103- 104 yr. For nearby objects, their expansion can be detected within years to decades. The pattern of expansion probes the internal velocity field and provides clues to the nebula ejection mechanism. In the case of non-symmetric nebulae, and bipolar nebulae in particular, it can a…
Compositional interpretation of PFS/MEx and TES/MGS thermal infrared spectra of Phobos
Duxbury, T.; Geminale, A.; Formisano, V. +4 more
The origin of the Martian satellites presents a puzzle of long standing. Addressing the composition of Phobos will help constrain theories of its formation. Visible and near-infrared spectra of Phobos lack deep absorption features, making the compositional interpretation a tricky task. PFS/MEx and TES/MGS observations in the thermal infrared show …
Detection of Supergranulation Alignment in Polar Regions of the Sun by Helioseismology
Zhao, Junwei; Kosovichev, Alexander G.; Sekii, Takashi +1 more
We report on a new phenomenon of "alignment" of supergranulation cells in the polar regions of the Sun. Recent high-resolution data sets obtained by the Solar Optical Telescope on board the Hinode satellite enabled us to investigate supergranular structures in high-latitude regions of the Sun. We have carried out a local helioseismology time-dista…
Water Production by Comet 103P/Hartley 2 Observed with the SWAN Instrument on the SOHO Spacecraft
Bertaux, J. -L.; Combi, M. R.; Quémerais, E. +2 more
Global water production rates were determined from the Lyα emission of hydrogen around comet 103P/Hartley 2, observed with the SWAN (Solar Wind Anisotropies) all-sky camera on the SOHO spacecraft from 2010 September 14 through December 12. This time period included the November 4 flyby by the EPOXI spacecraft. Water production was three times lowe…
First detection of hydrogen isocyanide (HNC) in Titan's atmosphere
Lara, L. M.; Hartogh, P.; Lellouch, E. +7 more
We report on the first identification of hydrogen isocyanide (HNC) in Titan's atmosphere, from observations using the HIFI instrument on the Herschel Space Observatory. An emission line from the HNC J = 6 → 5 rotational transition at 543.897 GHz was measured in Titan on June 14 and December 31, 2010. Radiative transfer modeling indicates that the …
Monitoring a high-amplitude δ Scuti star for 152 days: discovery of 12 additional modes and modulation effects in the light curve of CoRoT 101155310
Auvergne, M.; Baudin, F.; Poretti, E. +12 more
Aims: The detection of small-amplitude nonradial modes in high-amplitude δ Sct (HADS) variables has been very elusive until at least five of them were detected in the light curve of V974 Oph obtained from ground-based observations. The combination of radial and nonradial modes has a high asteroseismic potential, thanks to the strong constrain…
Study of the many fluorescent lines and the absorption variability in GX 301-2 with XMM-Newton
Wilms, J.; Ferrigno, C.; Pottschmidt, K. +7 more
We present an in-depth study of the high mass X-ray binary (HMXB) GX 301-2 during its pre-periastron flare using data from the XMM-Newton satellite. The energy spectrum shows a power law continuum absorbed by a large equivalent hydrogen column on the order of 1024 cm-2 and a prominent Fe Kα fluorescent emission line. Besides …
Electron dynamics in two-dimensional asymmetric anti-parallel reconnection
Pritchett, P. L.; Egedal, J.; Daughton, W. +1 more
Kinetic simulations and spacecraft observations have documented strong anisotropy in the electron distribution function during magnetic reconnection. The level and role of electron pressure anisotropy is investigated for asymmetric geometries applicable to reconnection in the day-side magnetopause. A previously derived analytic model for the press…