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Physical Sciences and Mathematics Commons™
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Full-Text Articles in Physical Sciences and Mathematics
Statistical Characteristics Ofsprite Halo Events Using Coincident Photometric And Imaging Data, R. Miyasato, Michael J. Taylor, H. Fukunishi, Y. Takahashi, H. Nielsen
Statistical Characteristics Ofsprite Halo Events Using Coincident Photometric And Imaging Data, R. Miyasato, Michael J. Taylor, H. Fukunishi, Y. Takahashi, H. Nielsen
All Physics Faculty Publications
Sprite halos are brief, diffuse flashes, which occur at the top of a sprite and precede the development of streamer structures at lower altitudes. We have investigated the characteristics of sprite halos in detail using coincident photometric and imaging data obtained during the Sprites'96 and '99 campaign in Colorado and Wyoming, USA. It is found that the average altitude of the centroid of the halo emission and the mean horizontal diameter of the halo events are ∼80 and ∼86 km, respectively, while the average speed of the descending motion of the sprite halos was ∼4.3 × 107 m/s. It …
Identification Of Cool White Dwarfs In The Noao Deep Wide-Field Survey, M. Kilic, Don E. Winget, T. Von Hippel, C.F. Claver
Identification Of Cool White Dwarfs In The Noao Deep Wide-Field Survey, M. Kilic, Don E. Winget, T. Von Hippel, C.F. Claver
Publications
The chronology of star formation is recorded in the white dwarf luminosity function (WDLF). White dwarf (WD) structure implies a relatively simple connection between WD luminosity and age. First attempts to exploit WDs as chronometers [3,4,6] showed that the WDLF was a map of the history of star formation in the disk, and a significant shortfall of low-luminosity degenerates–the inevitable consequence of the finite age of the disk. The shortfall near log(L/L⊙)≈−4.5 implies a disk age of 6.5–9.5 Gyr [2]. The WDLF from wide common proper motion binaries [5] does not show the shortfall seen by Liebert et al. (1988). …