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Short-Period Variable Be Stars Discovered or Confirmed through Self-Correlation Analysis of Hipparcos Epoch Photometry
Percy, John R.; Harlow, Christopher D. W.; Wu, Alice P. S.
We have surveyed 277 bright Be stars for short-period (0.2-2 day) photometric variability using self-correlation analysis of Hipparcos epoch photometry. This extends the work of Percy et al.; the methods are as described there. We report the discovery, timescale, and amplitude of short-period variability in: HD 7636 (V764 Cas), HD 11606 (V777 Cas)…
A cometary neutral gas simulator for gas dynamic sensor and mass spectrometer calibration
Wurz, P.; Altwegg, K.; Balsiger, H. +6 more
The goal of the European Space Agency's Rosetta mission is a rendezvous with the Edgewood-Kuiper Belt comet 67P/Churyumov-Gerasimenko. After the initial encounter the spacecraft will accompany the comet for one to two years toward the Sun and throughout the perihelion passage. For the calibration of the onboard comet mass spectrometers a calibrati…
The Phoenix Deep Survey: the radio properties of the hard X-ray-selected sample
Georgakakis, A.; Sullivan, M.; Mobasher, B. +3 more
The radio properties of hard (2-8 keV) X-ray-selected sources are explored by combining a single 50-ks XMM-Newton pointing with the ultradeep and homogeneous Phoenix radio (1.4-GHz) survey. A total of 43 sources are detected above the X-ray flux limit fX(2-8 keV) = 7.7 × 10-15 erg s-1 cm-2, with 14 of th…
Numerical Magnetohydrodynamic Experiments for Testing the Physical Mechanisms of Coronal Mass Ejections Acceleration
Liu, Yang; Feng, Xueshang; Zhang, T. X. +3 more
Analysis of observations from both space-borne (LASCO/SOHO, Skylab and Solar Maximum Mission) and ground-based (Mauna Loa Observatory) instruments show that there are two types of coronal mass ejections (CMEs), fast CMEs and slow CMEs. Fast CMEs start with a high initial speed, which remains more or less constant, while slow CMEs start with a low …
Stellar Populations in the Outer Reaches of M31 and M32 from WFPC2 Photometry
Mateo, Mario; Alonso-García, Javier; Worthey, Guy +1 more
Hubble Space Telescope Wide Field Planetary Camera 2 photometry in a field 7 effective radii from the nucleus of M32 and a comparison field in the outer disk of M31, already examined for the presence of RR Lyrae variable stars, are further compared. No relative distance difference between the two fields could be measured using the luminosity of re…
Composite Accretion Disk and White Dwarf Photosphere Analyses of the FUSE and Hubble Space Telescope Observations of EY Cygni
Sion, Edward M.; Orio, M.; Gänsicke, Boris T. +4 more
We explore the origin of FUSE and Hubble Space Telescope STIS far-UV spectra of the dwarf nova EY Cygni during its quiescence using combined high-gravity photosphere and accretion disk models, as well as model accretion belts. The best-fitting single-temperature white dwarf model to the FUSE plus STIS spectrum of EY Cyg has Teff=24,000 …
Shock wave driven by an expanding system of loops
Solanki, S. K.; Mierla, M.; Inhester, B. +5 more
We report on a Coronal Mass Ejection (CME) observed on June 27, 1999 by the UltraViolet Coronagraph Spectrometer (UVCS) telescope operating on board the SOHO spacecraft. The CME was also observed by the Large Angle Spectroscopic Coronagraph (LASCO). Emission of hot material has been recorded by UVCS propagating in front of an opening system of loo…
Kinematics and Parameters of the Gas in the Vicinity of TW Hya
Lamzin, S. A.; Kravtsova, A. S.; Romanova, M. M. +1 more
The following conclusions about the kinematics and parameters of the gas in the vicinity of TW Hya have been drawn from an analysis of optical and ultraviolet line profiles and intensities. The accreting matter rises in the magnetosphere to a distance z>R* above the disk plane and falls to the star near its equator almost perpendicul…
Observations of Nonthermal and Thermal Hard X-Ray Spikes in an M-Class Flare
Qiu, Jiong; Wang, Haimin; Ji, Haisheng +2 more
We report a study of an M2.3 flare, which occurred on 2002 September 9 in NOAA Active Region 0105. The observation was made at Big Bear Solar Observatory (BBSO) at the wavelength of Hα-1.3 Å, with a cadence of 40 ms. The flare was also observed by the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI). Three kernels appear in Hα-1.3 Å i…
Time-resolved photometry and spectroscopy of the new deeply-eclipsing SW Sextantis star HS 0728+6738
Gänsicke, B. T.; Hagen, H. -J.; Engels, D. +2 more
We present time-resolved optical spectroscopy and photometry, and far-ultraviolet spectroscopy of