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Updated ephemeris of Phoebe, ninth satellite of Saturn
Emelyanov, N. V.
Context: The theoretical model of natural satellite motion may need improvement each time new observations of a considerable amount are accumulated over a significant time interval.
Aims: The goal of our work is to elaborate the ephemeris of Phoebe based on all ground-based observations available to date and readily accessible for any user via…
Helical Eruptive Prominence Associated with a Pair of Overlapping CMEs on 21 April 2001
Vršnak, Bojan; Uddin, Wahab; Chandra, Ramesh +2 more
The eruption of limb prominence on 21 April 2001 associated with two coronal mass ejections (CMEs) is investigated. Hα images reveal two large-scale eruptions (a prominence body and a southern foot-point arch), both showing helical internal structure. These two eruptions are found to be spatially and temporally associated with the corresponding CM…
Resolving LB 11146 with Hubble Space Telescope's Fine Guidance Sensor
Nelan, Edmund P.
On the basis of its observed spectra, LB 11146 was identified as a binary system composed of pair of massive (~0.9 Modot) white dwarf stars. However, observations with the Hubble Space Telescope (HST) Faint Object Camera did not resolve the system, and searches for radial velocity variations yielded null results. Subsequent observations…
On the dynamical stability of the Rosetta orbiter. II.
Mysen, E.; Aksnes, K.
In an orbit around a comet, a spacecraft is subject to several spin-orbit resonances. These enhanced couplings, induced by the rotation of the nucleus, by temporal variations in the outgassing pressure field and, at last, by a rotation of the probe's solar cell arrays, are systematically mapped in this paper. Using the simplified pendulum model, e…
The Self-Inversion of the Sign of Circular Polarization in ``Halo'' Microwave Sources
Korzhavin, A. N.; Peterova, N. G.; Kaltman, T. I.
The large active region AR NOAA 5200 from October 1988 is used to investigate the concept of the "halo," a magnetosphere-like structure above the active region. This structure is studied by using radio spectral polarization observations with high spatial resolution obtained mainly with the radio telescope RATAN-600. In the case of AR 5200 the halo…
Keck NIRC2 photometry of Uranus, uranian satellites, and Triton in August 2004
Sromovsky, L. A.; Fry, P. M.
On August 11, 2004, we made adaptive optics observations of the Uranus and Neptune systems with the Keck II Near Infrared Camera. Uranus and Triton were observed in three broadband filters (J, H, and K-prime) and four narrowband filters [Hcont, FeII, He1_B, and H2(v=1-0)]. Miranda, Ariel, Umbriel, and Oberon were observed in the four narrowband fi…
Automated Selection and Characterization of Emission-Line Sources in Advanced Camera for Surveys Wide Field Camera Grism Data
Ford, H. C.; Meurer, Gerhardt R.; Capak, P. +10 more
We present complementary techniques to find emission-line targets and measure their properties in a semi-automated fashion from grism observations obtained with the Advanced Camera for Surveys aboard the Hubble Space Telescope (HST). The first technique is to find all likely sources in a direct image, extract their spectra, and search them for emi…
Understanding the origin of the solar cyclic activity for an improved earth climate prediction
Turck-Chièze, Sylvaine; Lambert, Pascal
This review is dedicated to the processes which could explain the origin of the great extrema of the solar activity. We would like to reach a more suitable estimate and prediction of the temporal solar variability and its real impact on the Earth climatic models. The development of this new field is stimulated by the SoHO helioseismic measurements…
Electromagnetic measurements on Martian soil analogs: Implications for MARSIS and SHARAD radars in detecting subsoil water
Pettinelli, Elena; Vannaroni, Giuliano; Cereti, Annamaria +1 more
In this work a laboratory investigation on the electrical and magnetic properties of magnetite-bearing and water-bearing granular mixtures, selected as Martian soil simulants, is presented. The objective of these measurements is the estimation of the performance of space-borne ground penetrating radars for detection of subsurface water (both solid…
An On-Orbit Determination of the On-Axis Point Spread Function of the Hinode X-Ray Telescope
Golub, Leon; Narukage, Noriyuki; Sakao, Taro +5 more
The Hinode X-ray Telescope provides unprecedented observations of the solar corona in X-rays, due in part to its fine resolution. The X-ray point spread function (PSF) was measured before launch at the NASA X-ray Calibration Facility to have a FWHM of 0.8''. This paper describes the work to verify the PSF measurements using on-orbit observations o…