Search Publications
Large Doppler Shifts in X-Ray Plasma: An Explosive Start to Coronal Mass Ejection
Schwenn, R.; Curdt, W.; Innes, D. E. +3 more
We report observations, taken with the Solar Ultraviolet Measurements of Emitted Radiation spectrometer, of spatially resolved high red and blue Doppler shifts (up to 650 km s-1) from X-ray-emitting plasma in the corona above a flare. The high Doppler shifts are seen minutes after a fast, faint optical front is seen racing through the s…
Constraints on the O+5 Anisotropy in the Solar Corona
Ofman, L.; Gary, S. P.; Viñas, A.
Velocity distributions of O+5 ions derived from Ultraviolet Coronagraph Spectrometer (UVCS) observations in coronal holes indicate that the O+5 ions are highly anisotropic (T⊥i/T∥i~30-300 at 3.5 Rsolar). The observations provide empirical values for the electron density and the ion temperature…
A Search for the Damped Lyα Absorber at z=1.86 toward QSO 1244+3443 with NICMOS
Schneider, Glenn; Rieke, Marcia J.; Kulkarni, Varsha P. +5 more
We have carried out a high-resolution imaging search for the galaxy associated with the damped Lyα absorber (DLA) at z=1.859 toward the zem=2.48 quasar QSO 1244+3443, using the Hubble Space Telescope (HST) and the near-infrared camera and multiobject spectrometer (NICMOS). Images were obtained in the broad filter F160W and the narrow fi…
FUSE Observations of U Geminorum during Outburst and Decline
Long, Knox S.; Drew, Janet E.; Froning, Cynthia S. +2 more
We have obtained far-ultraviolet (904-1187 Å) spectra of U Gem in outburst with the Far Ultraviolet Spectroscopic Explorer. Three of the observations were acquired during the plateau phase of the outburst, while the fourth was obtained during late outburst decline. The plateau spectra have continuum shapes and fluxes that are approximated by stead…
Investigation of USNO-A2.0 Catalog Positions
Teixeira, R.; Assafin, M.; Camargo, J. I. B. +4 more
We present an investigation of the USNO-A2.0 Catalog positions. We have compared USNO-A2.0 positions with the Astrographic Catalogue-Tycho, with improved HST Guide Star Catalog positions in the ACT frame, and with International Celestial Reference Frame source positions and observational data from Valinhos CCD Meridian Circle, covering all the USN…
Comparison of Empirical Models for Polar and Equatorial Coronal Holes
Romoli, M.; Cranmer, S. R.; Kohl, J. L. +2 more
We present a self-consistent empirical model for several plasma parameters of a large equatorial coronal hole observed on 1999 November 12 near solar maximum. The model was derived from observations with the Ultraviolet Coronagraph Spectrometer on the Solar and Heliospheric Observatory. In this Letter, we compare the observations of O VI λλ1032, 1…
WFPC2 Observations of Massive and Compact Young Star Clusters in M31
Williams, Benjamin F.; Hodge, Paul W.
We present color-magnitude diagrams of four blue massive and compact star clusters in M31: G38, G44, G94, and G293. The diagrams of the four clusters reveal a well-populated upper main sequence and various numbers of supergiants. The U-B and B-V colors of the upper main sequence stars are used to determine reddening estimates of the different line…
Photoevaporating Flows from the Cometary Knots in the Helix Nebula (NGC 7293)
Henney, W. J.; Raga, A. C.; López-Martín, L. +2 more
We explain the Hα emission of the cometary knots in the Helix Nebula (NGC 7293) with an analytical model that describes the emission of the head of the globules as a photoevaporated flow produced by the incident ionizing radiation of the central star. We compare these models with the Hα emission obtained from the Hubble Space Telescope (HST) archi…
Infrared Space Observatory Spectra of R Coronae Borealis Stars. I. Emission Features in the Interval 3-25 Microns
Rao, N. Kameswara; Lambert, David L.; Pandey, Gajendra +1 more
Infrared Space Observatory 3-25 µm spectra of the R Coronae Borealis stars V854 Cen, R CrB, and RY Sgr are presented and discussed. Sharp emission features coincident in wavelength with the well-known unidentified emission features are present in the spectrum of V854 Cen but not in the spectra of R CrB and RY Sgr. Since V854 Cen is not parti…
Coronal Inflows and Sector Magnetism
Sheeley, N. R., Jr.; Wang, Y. -M.
We have remeasured the rate of coronal inflows during 1996-2001, taking into account multiple occurrences per day, and have displayed the results in Carrington stack plots to study their long-term behavior. The stack plots show long-lived recurrence patterns related to the sectorial component of the Sun's large-scale field. In particular, most inf…