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Possible origin of the Saturn satellite, Phoebe

Brunini, A.; Di Sisto, R. P.

The orbit of the outermost Saturn's irregular moon, Phoebe, suggests that it was captured by Saturn rather than formed in situ. The Cassini-Huygens mission results allowed to find that Phoebe's composition is similar to that derived for the outer solar system bodies and very different from the composition of the Saturn regular satellites. In this …

Recent studies in satellite observations of three-dimensional magnetic reconnection

Zhao, H.; Liu, Z. X.; Pu, Z. Y. +5 more

An M1.5 Flare Triggered by a Multireconnection Process

Romano, P.; Contarino, L.; Zuccarello, F.

We studied the magnetic configuration of active region NOAA 10672, where two different mechanisms seem to contribute to its instability, to the subsequent M1.5 flare, and to a halo CME. The analysis of full-disk SOHO/MDI magnetograms and of WL and 171 Å TRACE images shows in fact that both flux emergence and horizontal displacements of photospheri…

Properties of the dust cloud caused by the Deep Impact experiment

Jorda, L.; Lara, L. M.; Lamy, P. +7 more

We present an analysis of the observations of the Deep Impact event performed by the OSIRIS narrow angle camera aboard the Rosetta spacecraft over two weeks, in an effort to characterize the cometary dust grains ejected from the nucleus of Comet 9P/Tempel 1. We adopt a Monte Carlo approach to generate calibrated synthetic images, and a linear comb…

Red giants in the blue compact galaxy IZw18

Tikhonov, N. A.

Archival Hubble Space Telescope (HST) data have been used for the photometry of stars in blue compact dwarf (BCD) galaxies of the IZw18 system. Applying the spatial selection of stars, we have detected red giants, stars older than 1 2 Gyr, in the galaxies. These red giants have allowed the distance to IZw18 to be reliably determined for the first …

A Method to Improve Binary Orbits by Incorporating Long-term Observational Data

Ren, Shu-lin; Fu, Yan-ning

Early ground-based observations have accumulated a large volume of data on binary stellar systems. Compared to the more recent data obtained by various new techniques, these older data have both the disadvantage of low precision and the advantage of long time-span. For long-period binary systems having available both long-term data and Hipparcos d…

Several problems in measuring solar vector magnetic fields

Zhang, H. Q.; Ruan, G. P.; Su, J. T. +1 more

Observations of solar photosphere vector magnetic fields with a magnetograph are subjected to many difficulties, such as azimuth ambiguity, magnetic saturation, Faraday rotation, scattered light, polarization crosstalk, and wavelength shift, and so on. Among these issues, Faraday rotation and scattered light are obvious in local-region vector magn…

Precession Constant Correction and Proper Motion Systems of FK5 and Hipparcos

Zhu, Zi

Results of many researches have shown that the relation between the proper motion systems of FK5 and Hipparcos is not consistent with the precession constant corrections determined by VLBI and LLR. We analysed proper motion data of PPM and ACRS based on the FK5 system for many different sub-samples and found that consistent values of the precessio…

Wavelet analysis of fine-scale structures in the Saturnian B and C rings using data from the Cassini spacecraft

Postnikov, E. B.; Loskutov, A. Yu.

A continuous wavelet transform with a complex Morlet basis offers an effective method for the analysis of an instant variable periodicity in the spatially inhomogeneous matter density in the radial structure of Saturn’s rings. An original algorithm that reduces the integral transform to solving a Cauchy problem for a partial differential equation …

Hot and Cool Loops Composing the Corona of the Quiet Sun

Hara, Hirohisa; Culhane, Len; Watanabe, Tetsuya +3 more

We performed a raster scan observation of the quiet Sun with the EUV Imaging Spectrometer (EIS) aboard Hinode and simultaneously analyzed observed emission lines of Fe VIII to XV. From a combined analysis, radiance maps from the observed emission lines were deconvolved into plasma components at five representative temperatures between 0.40MK and 2…