Search Publications
HST Spectroscopy of PG 1159 Stars: the Boundary of the GW VIR Instability Strip
Dreizler, S.
Our recent analysis of PG 1159 stars, mainly based on the HST spectroscopy, is presented. The results allow several conclusions regarding the boundary of the GW Vir instability strip and the driving mechanism for these pulsations.
Weak lensing analysis of CL 1358+62
Franx, Marijn; Hoekstra, Henk; Kuijken, Konrad +1 more
We report on the detection of weak gravitational lensing of faint, distant background objects by Cl 1358+62, a rich cluster of galaxies at a redshift of z = 0.33. The observations consist of a multicolor mosaic of 12 WFPC2 pointings of the Hubble Space Telescope (HST). We find a projected mass of (4.4±0.6) × 10 14 M ⊙ within …
Hubble Space Telescope Observations of Planetary Nebulae in the Magellanic Clouds. VI. Cycles 4 and 5 Ultraviolet Spectroscopy Using the Faint Object Spectrograph
Ford, H. C.; Harrington, J. P.; Wood, P. R. +6 more
The Faint Object Spectrograph on board the Hubble Space Telescope (HST) is used to obtain spectra in the wavelength range λλ1150-4800 of three planetary nebulae in the Small Magellanic Cloud and 10 planetary nebulae in the Large Magellanic Cloud. This sample extends the sample of 12 objects previously observed with HST and reported in the third pa…
The Mass of the Cepheid Binary V636 Scorpii
Albrow, Michael D.; Cottrell, P. L.; Evans, N. R. +4 more
The mass-luminosity relation for Cepheids depends on the degree of mixing in their main-sequence progenitors. Masses of Cepheids can be inferred by using different aspects of pulsation theory. These methods have in the past led to diverging results, showing that something was wrong in either evolution theory or pulsation theory or both. For some b…
High velocity gas and dust evolution in Chamaeleon clouds
Boulanger, Francois; Falgarone, Edith; Gry, Cecile +2 more
We report on GHRS observations which reveal conspicuous differences in the absorption spectra of two nearby stars, close to each other. The star HD102065 lies behind a cloud in Chamaeleon with unusually strong mid-IR emission, indicating a large abundance of very small dust particles. Along this line of sight, 5% of the gas (about 6 10(19) cm(-2) …
CCD photometry of variable stars in the Magellanic Clouds - VI. The eclipsing binary HV982 in the Large Magellanic Cloud
Guinan, E. F.; Pritchard, J. D.; Tobin, W. +1 more
Using improved techniques, high-quality CCD uvbyVI photometry has been obtained for the eclipsing binary HV982 in the Large Magellanic Cloud (LMC). International Ultraviolet Explorer ultraviolet spectrophotometry was also obtained. These data have been analysed using the Wilson-Devinney synthetic light-curve code and Kurucz low-metallicity model a…
Interstellar Absorption Lines in the Spectrum of the Starburst Galaxy NGC 1705
Sahu, M. S.
A Goddard High Resolution Spectrograph archival study of the interstellar absorption lines in the line of sight to the H i-rich, starburst dwarf galaxy NGC 1705 in the 1170 to 1740 Å range at ~120 km s^-1 resolution is presented. The absorption features arising because of photospheric lines are distinctly different from the interstellar lines: the…
UVBY photometry of 33 Tauri, HD 50169, and HR 7786 and an assessment of FCAPT comparison stars
Adelman, S. J.; Pi, C. -L. M.; Rayle, K. E.
Differential Strömgren uvby photometric observations from the Four College Automated Photoelectric Telescope are presented for the ellipsoidal variable 33 Tauri, and the magnetic Chemically Peculiar stars HD 50169 and HR 7786. We confirm that Hube's period of 2.975272 days for 33 Tau is correct. HD 50169 is a constant MCP star. HR 7786 is a large …
Physical properties of the quiescent prominence of 5June 1996, from Hα observations
Schmieder, B.; Roudier, Th.; Malherbe, J. -M. +2 more
The Multichannel Subtractive Double Pass spectrograph (MSDP) is designed to observe line profiles in a 2D field of view with a good spatial and temporal resolution. In order to deal with this unique opportunity, we introduce a new method for fitting the hydrogen Hα line formed in prominences and deriving various plasma parameters from line profile…
Radial evolution of ejecta characteristics and transient shocks: Ulysses in-ecliptic observations
Smith, E. J.; Neugebauer, M.; Phillips, J. L. +1 more
During its travel to Jupiter, Ulysses detected 25 ejecta and 32 transient forward shocks (TFS), and in the first 3 months after the Jupiter flyby Ulysses detected 9 ejecta and 5 TFS. Half of these ejecta (17) were associated with TFS. We identified the ejecta using bidirectional streaming of suprathermal electrons accompanied by other plasma cloud…