Search Publications
The Distance to the Hyades Cluster Based on Hubble Space Telescope Fine Guidance Sensor Parallaxes
Kozhurina-Platais, V.; Benedict, G. F.; Franz, O. G. +24 more
Trigonometric parallax observations made with the Hubble Space Telescope (HST) Fine Guidance Sensor (FGS) 3 of seven Hyades members in six fields of view have been analyzed along with their proper motions to determine the distance to the cluster. Knowledge of the convergent point and mean proper motion of the Hyades is critical to the derivation o…
Comparison of IUE and HST diagnostics of the Jovian Aurorae
Livengood, T.; Harris, W. M.; Prangé, R. +2 more
Analysis of international ultraviolet explorer (IUE) and Voyager ultraviolet spectrometer (UVS) spectra of the Jovian auroral emission indicates that the Jovian auroral brightness is modulated in longitude (brighter near 180° in the north and 20° in the south) and that there is a color ratio asymmetry associated with this brightening. The purpose …
The dynamical mass of the beat cepheid Y carinae and stellar opacities.
Bohm-Vitense, E.; Evans, N. R.; Carpenter, K. +3 more
The beat Cepheid, Y Carinae A, has a B9 V companion, Y Car B. The primary period P0 of the Cepheid is 3.64 days and the secondary, P1, is 2.56 days. Its period ratio P1/P0 is thus 0.703. Y Car is the only beat Cepheid known to be a binary and thus offers us the unique opportunity to determine the dynamic…
The Mount Wilson Halo Mapping Project 1975-1985 I: The UBV(RI)_M_W Photometric System Compared with Other Standard Systems: The Adopted Trigonometric HR Diagram in (R-I)_M_W and (V-I)_M_W
Sandage, A.
Photometry of stars is described that defines a UBV(RI)_M_W photometric system, established between 1975 and 1980 using the Mount Wilson 60-inch and 100-inch reflectors. The MW natural system has been reduced to the UBV(RI)_C Cape-Cousins system by linear equations for stars hotter than M0. Strong non-linear color and magnitude equations exit in R…
Particle acceleration at corotating reverse shocks in the southern hemisphere: Ulysses results
Balogh, A.; Forsyth, R. J.; Desai, M. I. +3 more
We have correlated the ∼1 MeV proton intensity (J) measured at corotating reverse shocks detected by Ulysses in the southern hemisphere with two parameters that characterise the strength of the shock. Between 6°-29°S J is essentially independent of the shock strength, whereas between 29°-41°S J is well correlated with the same. The poor correlatio…
Hubble Space Telescope Faint Object Camera calculated point-spread functions
Hollis, J. M.; Dorband, J. E.; Lyon, R. G.
A set of observed noisy Hubble Space Telescope Faint Object Camera point-spread functions is used to recover the combined Hubble and Faint Object Camera wave-front error. The low-spatial-frequency wave-front error is parameterized in terms of a set of 32 annular Zernike polynomials. The midlevel and higher spatial frequencies are parameterized in …
Astrometry of the globular cluster 47 Tucanae and possible optical identification of X-ray sources.
Koch-Miramond, L.; Auriere, M.; Geffert, M.
Positions of stars of 47 Tuc have been derived by the use of photographic plates and CCD frames (ESO La Silla) and data from the Hubble Space Telescope (HST). The positions have been determined with respect to the PPM, which is based on the FK5 system. We have compared the positions of variable and blue stars in the core of 47 Tuc with those of th…
Astronomical Search and Laboratory Spectroscopy of the FeCO Radical
Kagi, Eriko; Kasai, Yasuko; Ungerechts, Hans +1 more
The millimeter and submillimeter spectrum of the FeCO radical in the 3Σ- ground electronic state has been observed in the laboratory. The radical was generated by a DC glow discharge in a mixture of Fe(CO)5 and argon. A total of 33 rotational transitions in the three spin sublevels with Ω = 1, 0 were observed in th…
Recurrence of Energetic Particle Flux Anisotropy as Observed by ERNE on 9 July 1996
Laitinen, T.; Vainio, R.; Valtonen, E. +3 more
A solar energetic particle event was observed on 9 July 1996, by the ERNE sensors LED and HED on board the SOHO spacecraft. The arrival of the first protons in the energy range >20 MeV took place at 09:55 UT, 43 min after the maximum in the X-ray and Hα radiation of a flare located at S10 W30. The rise phase of the particle intensities at all e…
Statistical Properties of the Big Blue Bump in Active Galactic Nuclei
Wang, J. M.; Zhou, Y. Y.; Yu, K. N. +2 more
The shape is the most important characteristic of the big blue bump (bbb). By employing the sample from Walter & Fink, and supplementing it with medium energy X-ray data, we have been successful in separating the bbb component from the nonthermal component for the soft X-ray region and thus obtaining the cutoff energy Ecut of the bi…