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On the outflow in an equatorial coronal hole
Marsch, E.; Curdt, W.; Xia, L. D.
We report new observations concerning the source of the fast solar wind by directly comparing Doppler-shift maps of Ne7+ with charts of the photospheric magnetic field in an equatorial coronal hole, which was observed by SUMER/SOHO and NSO/Kitt Peak on November 5, 1999. The relationship between the velocity field, line intensity and mag…
Target Selection for SETI. I. A Catalog of Nearby Habitable Stellar Systems
Turnbull, Margaret C.; Tarter, Jill C.
In preparation for the advent of the Allen Telescope Array, the SETI Institute has the need to greatly expand its former list of ~2000 targets compiled for Project Phoenix, a search for extraterrestrial technological signals. In this paper we present a catalog of stellar systems that are potentially habitable to complex life forms (including intel…
ULF wave identification in the magnetosheath: The k-filtering technique applied to Cluster II data
Balogh, A.; Belmont, G.; Sahraoui, F. +8 more
The magnetic fluctuations in the magnetosheath are studied, thanks to Cluster II data. The k-filtering technique is applied to explore ULF magnetic fluctuations using STAFF (Spatio-Temporal Analysis of a Field Fluctuations) data. Based on multipoint measurements, the k-filtering technique allows, for the first time, to estimate the Magnetic Field …
The Observation of Sunspot Light-Bridge Structure and Dynamics
Berger, T. E.; Berdyugina, S. V.
We present very high resolution multiwavelength images of a sunspot light bridge in NOAA Active Region 10132 taken at the Swedish 1 m Solar Telescope on La Palma on 2002 September 25. The adaptive optics-corrected images resolve 100 km scale bright grains on either side of an approximately 380 km dark lane in the center of the bridge. Movies of th…
Observational Constraints on Disk Heating as a Function of Hubble Type
Shapiro, Kristen L.; Gerssen, Joris; van der Marel, Roeland P.
Current understanding of the secular evolution of galactic disks suggests that this process is dominated by two or more ``heating'' mechanisms, which increase the random motions of stars in the disk. In particular, the gravitational influence of giant molecular clouds and irregularities in the spiral potential have been proposed to explain the obs…
Rotation, pulsations and magnetic field in V 2052 Ophiuchi : A new He-strong star
Frémat, Y.; Neiner, C.; Jankov, S. +7 more
Three years in the coronal life of AB Dor. I. Plasma emission measure distributions and abundances at different activity levels
Sanz-Forcada, J.; Micela, G.; Maggio, A.
The young active star AB Dor (K1 IV-V) has been observed 16 times in the last three years with the XMM-Newton and Chandra observatories, totalling 650 ks of high-resolution X-ray spectra. The XMM/RGS observations with the highest and lowest average emission levels have been selected to study the coronal properties of AB Dor in two different activi…
Imaging and Spectroscopic Investigations of a Solar Coronal Wave: Properties of the Wave Front and Associated Erupting Material
Harra, Louise K.; Sterling, Alphonse C.
Using spectral data from the Coronal Diagnostic Spectrometer (CDS) instrument on the Solar and Heliospheric Observatory spacecraft, we observe a coronal wave feature (often referred to as an EIT wave) that occurred in association with a solar eruption and flare on 1998 June 13. EUV images from the Transition Region and Coronal Explorer (TRACE) sat…
An Extensive Census of Hubble Space Telescope Counterparts to Chandra X-Ray Sources in the Globular Cluster 47 Tucanae. II. Time Series and Analysis
Heinke, Craig O.; Gilliland, Ronald L.; Edmonds, Peter D. +1 more
We report time series and variability information for the optical identifications of X-ray sources in 47 Tucanae reported in Paper I (at least 22 cataclysmic variables [CVs] and 29 active binaries). The radial distribution of the CVs is indistinguishable from that of the millisecond pulsars (MSPs) detected by Freire et al. A study of the eight CVs…
Oxygen Gas-Phase Abundance Revisited
Moos, H. W.; André, M. K.; Ferlet, R. +7 more
We present new measurements of the interstellar gas-phase oxygen abundance along the sight lines toward 19 early-type Galactic stars at an average distance of 2.6 kpc. We derive O I column densities from Hubble Space Telescope/Space Telescope Imaging Spectrograph (HST/STIS) observations of the weak 1355 Å intersystem transition. We derive total hy…