* Astronomy

Blobrana · L

M-5 Rocket body Re-entry

Blobrana · L

A Japanese M-5 Rocket body that was launched on the 22nd September, 2006, from the Kagoshima Space Centre, on the Hinode (SOLAR B) mission, is predicted to re-enter the Earths atmosphere on the 1st October, 2009.

TLE Data

M-5 RB
1 29480U 06041B   09245.82351863 +.00119519 +86297-5 +18523-3 0 09760
2 29480 098.2657 084.8379 0060670 187.5484 172.4887 16.00565122167512

Period:        89.97 minutes
Inclination: 98.27°
Apogee:     313 km
Perigee:      233 km
Size:            9 metres

Blobrana · L

RE: SOLAR-B Satellite

Blobrana · L

Title: Hinode Observations of Magnetic Elements in Internetwork Areas
Authors: A.G. de Wijn, B.W. Lites, T.E. Berger, Z.A. Frank, T.D. Tarbell, R. Ishikawa

We use sequences of images and magnetograms from Hinode to study magnetic elements in internetwork parts of the quiet solar photosphere. Visual inspection shows the existence of many long-lived (several hours) structures that interact frequently, and may migrate over distances ~7 Mm over a period of a few hours. About a fifth of the elements have an associated bright point in G-band or Ca II H intensity. We apply a hysteresis-based algorithm to identify elements. The algorithm is able to track elements for about 10 min on average. Elements intermittently drop below the detection limit, though the associated flux apparently persists and often reappears some time later. We infer proper motions of elements from their successive positions, and find that they obey a Gaussian distribution with an rms of 1.57±0.08 km/s. The apparent flows indicate a bias of about 0.2 km/s toward the network boundary. Elements of negative polarity show a higher bias than elements of positive polarity, perhaps as a result of to the dominant positive polarity of the network in the field of view, or because of increased mobility due to their smaller size. A preference for motions in X is likely explained by higher supergranular flow in that direction. We search for emerging bipoles by grouping elements of opposite polarity that appear close together in space and time. We find no evidence supporting Joy's law at arcsecond scales.

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Blobrana · L

Title: Intensity oscillations observed with Hinode near the south pole of the Sun: leakage of low frequency magneto-acoustic waves into the solar corona
Authors: A.K. Srivastava, D. Kuridze, T.V. Zaqarashvili

Aims. To study intensity oscillations in the solar chromosphere/corona above a quiet-Sun magnetic network.
Methods. We analyse the time series of He II 256.32, Fe XI 188.23 and Fe XII 195.12 spectral lines observed by EUV Imaging Spectrometer (EIS) on board Hinode near the south pole. Then we use a standard wavelet tool to produce power spectra of intensity oscillations above the magnetic network.
Results. We get ~7 min intensity oscillations in all spectral lines and ~13 min intensity oscillations only in He II with the probability of ~96-98 %, which probably reflects the process of magneto-acoustic wave propagation above the network.
Conclusions. We suggest that field-free cavity areas under bipolar magnetic canopies in the vicinity of magnetic network may serve as resonators for the magneto-acoustic waves. The cavities with photospheric sound speed and granular dimensions may produce the waves with the observed periods. The waves may propagate upwards in the transition region/corona and cause observed intensity oscillations.

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Blobrana · L

Title: Penumbral models in the light of Hinode spectropolarimetric observations
Authors: J. Jurcak, L.R. Bellot Rubio
(Version v2)

The realism of current models of the penumbra is assessed by comparing their predictions with the plasma properties of penumbral filaments as retrieved from spectropolarimetric observations. The spectropolarimeter onboard Hinode allows us to distinguish for the first time the fine structure of the penumbra. Therefore, we can use one-component inversions to obtain the stratifications of plasma parameters in each pixel. The correlations between the plasma parameters and the continuum intensity are studied. We find that, in the outer penumbra, the stronger flows and higher values of magnetic field inclination tend to be located in dark filaments. This finding does not seem to be compatible with the scenario of a field-free gappy penumbra.

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Blobrana · L

Title: Umbral Fine Structures in Sunspots Observed with Hinode Solar Optical Telescope
Authors: Reizaburo Kitai, Hiroko Watanabe, Tahei Nakamura, Ken-ichi Otsuji, Takuma Matsumoto, Satoru UeNo, Shin-ichi Nagata, Kazunari Shibata, Richard Muller, Kiyoshi Ichimoto, Saku Tsuneta, Yoshinori Suematsu, Yukio Katsukawa, Toshifumi Shimizu, Theodore D. Tarbell, Richard A. Shine, Alan M. Title, Bruce W. Lites

High resolution imaging observation of a sunspot umbra was done with Hinode Solar Optical Telescope (SOT). Filtergrams in wavelengths of blue and green continuum were taken during three consecutive days. The umbra consisted of a dark core region, several diffuse components and numerous umbral dots. We derived basic properties of umbral dots (UDs), especially their temperatures, lifetimes, proper motions, spatial distribution and morphological evolution. Brightness of UDs is confirmed to depend on the brightness of their surrounding background. Several UDs show fission and fusion. Thanks to the stable condition of space observation, we could first follow the temporal behaviour of these events. The derived properties of internal structure of the umbra are discussed in viewpoint of magnetoconvection in a strong magnetic field.

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Blobrana · L

Title: Initial Helioseismic Observations by Hinode/SOT
Authors: Takashi Sekii, Alexander G. Kosovichev, Junwei Zhao, Saku Tsuneta, Hiromoto Shibahashi, Thomas E. Berger, Kiyoshi Ichimoto, Yukio Katsukawa, Bruce W. Lites, Shin'ichi Nagata, Toshifumi Shimizu, Richard A. Shine, Yoshinori Suematsu, Theodore D. Tarbell, Alan M. Title

Results from initial helioseismic observations by Solar Optical Telescope onboard Hinode are reported. It has been demonstrated that intensity oscillation data from Broadband Filter Imager can be used for various helioseismic analyses. The k-omega power spectra, as well as corresponding time-distance cross-correlation function that promises high-resolution time-distance analysis below 6-Mm travelling distance, were obtained for G-band and CaII-H data. Subsurface supergranular patterns have been observed from our first time-distance analysis. The results show that the solar oscillation spectrum is extended to much higher frequencies and wavenumbers, and the time-distance diagram is extended to much shorter travel distances and times than they were observed before, thus revealing great potential for high-resolution helioseismic observations from Hinode.

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Blobrana · L

Title: Hinode EUV Imaging Spectrometer Observations of Solar Active Region Dynamics
Authors: John T. Mariska, Harry P. Warren, Ignacio Ugarte-Urra, David H. Brooks, David R. Williams, Hirohisa Hara

The EUV Imaging Spectrometer (EIS) on the Hinode satellite is capable of measuring emission line centre positions for Gaussian line profiles to a fraction of a spectral pixel, resulting in relative solar Doppler-shift measurements with an accuracy of less than a km/s for strong lines. We show an example of the application of that capability to an active region sit-and-stare observation in which the EIS slit is placed at one location on the Sun and many exposures are taken while the spacecraft tracking keeps the same solar location within the slit. For the active region examined (NOAA 10930), we find that significant intensity and Doppler-shift fluctuations as a function of time are present at a number of locations. These fluctuations appear to be similar to those observed in high-temperature emission lines with other space-borne spectroscopic instruments. With its increased sensitivity over earlier spectrometers and its ability to image many emission lines simultaneously, EIS should provide significant new constraints on Doppler-shift oscillations in the corona.

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-- Edited by Blobrana at 12:19, 2007-09-03

Blobrana · L

A year after launch, scientists working with Hinode, a Japanese mission with ESA participation, are meeting at Trinity College, Dublin, to discuss latest findings on solar mysteries - including new insights on solar flares and coronal heating.
Highlights include new insights on the workings of solar flares and on the mechanism behind coronal heating.

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