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Challenging the Carbon Star Dust Condensation Sequence: Anarchist C Stars
Speck, Angela K.; Corman, Adrian B.; Thompson, Grant D. +1 more
There have been several investigations of the evolution of the mid-infrared (IR) dust features in carbon star spectra based on IRAS LRS data, but these studies are somewhat contradictory. In order to understand these differences in interpretations and to develop an understanding of the carbon star dust sequence, we have reexamined 26 IRAS LRS spec…
Improved oscillator strengths and wavelengths in Hf II, with applications to stellar elemental abundances
Nilsson, H.; Leckrone, D. S.; Lundberg, H. +4 more
Aims. We present new and improved radiative lifetimes for eight levels in Hf I and 18 levels in Hf II, along with oscillator strengths and wavelengths for 195 transitions in Hf II. With these data we determine the abundance of hafnium in two chemically peculiar stars: the hot-Am star HR 3383 and the HgMn star χ Lupi, and discuss the implications o…
A multi-satellite study of accelerated ionospheric ion beams above the polar cap
Balogh, A.; Rème, H.; Grigorenko, E. +7 more
This paper presents a study of nearly field-aligned outflowing ion beams observed on the Cluster satellites over the polar cap. Data are taken at geocentric radial distances of the order of 5-9 RE. The distinction is made between ion beams originating from the polar cusp/cleft and beams accelerated almost along the magnetic field line p…
Adaptive Optics Imaging of Low-Redshift Damped Lyα Quasar Absorbers
Kulkarni, Varsha P.; Chun, Mark R.; Gharanfoli, Soheila +1 more
We have carried out a high angular resolution near-infrared imaging study of the fields of six quasars with seven strong absorption-line systems at z<0.5, using the Hokupa'a adaptive optics system and the Quick Infrared Camera on the Gemini North telescope. These absorption systems include four classical damped Lyα absorbers (DLAs), two sub-DLA…
Magnetic structure of the solar transition region as observed in various ultraviolet lines emitted at different temperatures
Tu, C. -Y.; Marsch, E.; He, J. -S. +1 more
Aims.The structure of the solar transition region (TR) in a polar coronal hole of the Sun is studied. In particular, the detailed association of the coronal magnetic field (carpet) with the radiance patterns of the TR, when seen in various far ultraviolet (FUV) emission lines, is investigated.
Methods: .A detailed comparison is made of the cor…
The Inner Resonance Ring of NGC 3081. II. Star Formation, Bar Strength, Disk Surface Mass Density, and Mass-to-Light Ratio
Byrd, Gene G.; Freeman, Tarsh; Buta, Ronald J.
We complement our Hubble Space Telescope (HST) observations of the inner ring of the galaxy NGC 3081 using an analytical approach and n-body simulations. We find that a gas cloud inner (r) ring forms under a rotating bar perturbation with very strong azimuthal cloud crowding where the ring crosses the bar major axis. Thus, star formation results n…
FAST TRACK PAPER: The SGR 1806-20 magnetar signature on the Earth's magnetic field
Mandea, M.; Balasis, G.
SGRs denote `soft γ-ray repeaters', a small class of slowly spinning neutron stars with strong magnetic fields. On 2004 December 27, a giant flare was detected from magnetar SGR 1806-20. The initial spike was followed by a hard-X-ray tail persisting for 380 s with a modulation period of 7.56 s. This event has received considerable attention, parti…
Luminosity Function of Faint Globular Clusters in M87
Zepf, Stephen E.; Lauer, Tod R.; Waters, Christopher Z. +2 more
We present the luminosity function to very faint magnitudes for the globular clusters in M87, based on a 30 orbit Hubble Space Telescope (HST) WFPC2 imaging program. The very deep images and corresponding improved false source rejection allow us to probe the mass function further beyond the turnover than has been done before. We compare our lumino…
Near-infrared adaptive optics dissection of the core of NGC 1068 with NAOS-CONICA
Rouan, D.; Gendron, E.; Fusco, T. +4 more
We present an update analysis of recent near-infrared adaptive optics observations of
Ulysses jovian latitude scan of high-velocity dust streams originating from the jovian system
Flandes, Alberto; Krüger, Harald; Hamilton, Douglas P. +4 more
In February 2004 the Ulysses spacecraft had its second flyby at Jupiter at 0.8 AU distance from the planet. Twenty-eight dust streams emanating from the jovian system were measured between November 2002 and August 2005 while the spacecraft was within 4 AU of the planet, scanning jovigraphic latitudes from +75∘ to -25∘. The hi…