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Central Stars of Planetary Nebulae in the Large Magellanic Cloud: A Far-Ultraviolet Spectroscopic Analysis
Bianchi, L.; Herald, J. E.
We observed seven central stars of planetary nebulae (PNe) in the Large Magellanic Cloud (LMC) with the Far Ultraviolet Spectroscopic Explorer and performed a model-based analysis of these spectra in conjunction with Hubble Space Telescope spectra in the UV and optical range to determine the stellar and nebular parameters. Most of the objects show…
Studies of orbital parameters and pulse profile of the accreting millisecond pulsar XTE J1807-294
Freyberg, M. J.; Kendziorra, E.; Smith, M. J. S. +4 more
The accreting millisecond pulsar XTE J1807-294 was observed as a Target of Opportunity (ToO) by XMM-Newton on March 22, 2003 after its discovery on February 21, 2003 by RXTE. The source was detected in its bright phase with an observed average count rate of 33.3 cts s-1 in the EPIC-pn camera in the 0.5-10 keV energy band (3.7 mCrab). Us…
Resolving the Nature of the Large Magellanic Cloud Microlensing Event MACHO-LMC-5
Cook, K. H.; Drake, A. J.; Keller, S. C.
We present the results from an analysis of Hubble Space Telescope high-resolution camera data for the Large Magellanic Cloud microlensing event MACHO-LMC-5. By determining the parallax and proper motion of this object, we find that the lens is an M dwarf star at a distance of 578+65-53 pc with a proper motion of 21.39+/-0.04 …
Orientation and motion of a discontinuity from Cluster curlometer capability: Minimum variance of current density
Klecker, B.; Vaivads, A.; Dunlop, M. W. +4 more
A new technique to derive magnetopause key parameters such as orientation, velocity and thickness from multi-spacecraft observations is presented. The method is based on four-spacecraft determination of the current density, variance analysis to estimate the orientation and thereafter integration of the current density across the magnetopause to fi…
Dynamical mass estimates for two luminous young stellar clusters in Messier 83
Larsen, S. S.; Richtler, T.
Using new data from the UVES spectrograph on the ESO Very Large Telescope and archive images from the Hubble Space Telescope, we have measured projected velocity dispersions and structural parameters for two bright young star clusters in the nearby spiral galaxy
Effects of Metallicity on the Rotational Velocities of Massive Stars
Gies, Douglas R.; Penny, Laura R.; Sprague, Amanda J. +1 more
Recent theoretical predictions for low-metallicity massive stars predict that these stars should have drastically reduced equatorial winds (mass loss) while on the main sequence, and so should retain most of their angular momentum. Observations of both the Be/(B+Be) ratio and the blue-to-red supergiant ratio appear to have a metallicity dependence…
The strange physics of low frequency mirror mode turbulence in the high temperature plasma of the magnetosheath
Nakamura, R.; Constantinescu, O. D.; Treumann, R. A. +3 more
Mirror mode turbulence is the lowest frequency perpendicular magnetic excitation in magnetized plasma proposed already about half a century ago by Rudakov and Sagdeev (1958) and Chandrasekhar et al. (1958) from fluid theory. Its experimental verification required a relatively long time. It was early recognized that mirror modes for being excited r…
Visible spectral properties of asteroid 21 Lutetia, target of Rosetta Mission
Barbieri, C.; Lazzarin, M.; Marchi, S. +1 more
Rosetta spacecraft was successfully launched on March 2nd 2004 after its launch postponement in January 2003. Owing to this delay all the original targets, comet and asteroids, have been changed. In particular, on its 10 years journey to the new comet 67P/Churyumov-Gerasimenko, the spacecraft will pass close to the asteroid 21 Lutetia. In this pap…
The Galactic Inner Halo: Searching for White Dwarfs and Measuring the Fundamental Galactic Constant, Θ0/R0
Rich, R. Michael; Gibson, Brad K.; Stetson, Peter B. +9 more
We establish an extragalactic, zero-motion frame of reference within the deepest optical image of a globular star cluster, a Hubble Space Telescope (HST) 123 orbit exposure of M4 (GO 8679, Cycle 9). The line of sight beyond M4 (l,b=351deg,16deg) intersects the inner halo (spheroid) of our Galaxy at a tangent-point distance of…
An Erupting Classical Nova in a Globular Cluster of M87
Zurek, David R.; Lauer, Tod R.; Shara, Michael M. +2 more
Only one certain classical nova eruption has ever been detected inside a globular cluster-nova T Sco (observed in A.D. 1860) in M80. During a survey of M87 we have detected an erupting star coincident (to within 0.08 pixels) with a globular cluster of that giant elliptical galaxy. We are able to discount variables in the foreground or background o…