Search Publications
Ultraviolet spectral properties of magellanic and non-magellanic irregulars, H BT II and starburst galaxies
Alloin, D.; Pastoriza, M. G.; Bonatto, C. +1 more
This paper presents the results of a stellar population analysis performed on nearby (V_R<=5 000 km s^{-1}) star-forming galaxies, comprising magellanic and non-magellanic irregulars, H Ii and starburst galaxies observed with the IUE satellite. Before any comparison of galaxy spectra, we have formed subsets according to absolute magnitude and m…
Parameters of the Galactic rotation curve and spiral pattern from Cepheid kinematics
Mishurov, Yu. N.; Zenina, I. A.
A method is developed for analyzing stellar velocity fields in our Galaxy, with allowance for spiral-density-wave perturbations. The parameters of the Galactic rotation curve, spiral pattern, and mean solar motion are inferred using new Cepheid radial velocities and proper motions measured by the HIPPARCOS space telescope. The Sun is very close to…
CCD photometry and astrometry of visual double and multiple stars of the HIPPARCOS Catalogue. II. CCD photometry and differential astrometry of 288 southern ``Intermediate'' systems
Cuypers, J.; Seggewiss, W.
We present photometric and astrometric data of about 280 visual double stars of the ``intermediate'' class, i.e. with angular separations mainly in the range 2arcsec < rho < 12arcsec . The observations have been obtained in 1991-92 with a CCD camera attached to the 91 cm Dutch telescope at ESO La Silla, Chile. Differential magnitudes of the …
Adaptive Optics Observations of Arcturus using the Mount Wilson 100 Inch Telescope
Mason, Brian D.; ten Brummelaar, Theo A.; Turner, Nils H.
Upon inspection of the multiple-star results in the Hipparcos catalog, the flag for entry number 69673 particularly stands out; it is Arcturus, for which no companion has been reported previously. The Hipparcos companion is reported to be at a separation of 0.255"+/-0.039" with a magnitude difference in a broadband filter (peaked near 460 nm) of 3…
New spectroscopic components in 8 multiple systems
Tokovinin, A. A.
New close sub-systems are discovered in 8 visual late-type double stars. Elements of spectroscopic orbits (4 double-lined and 4 single-lined) are given for the components of quadruple systems ADS 1134 and 11163, for the components of triple systems ADS 455, 497, 5436, 8236, 10044, and for the primary of the optical pair ADS 9444. Magnitudes, color…
The Early Palomar Program (1950-1955) for the Discovery of Classical Novae in M81: Analysis of the Spatial Distribution, Magnitude Distribution, and Distance Suggestion
Zurek, David R.; Shara, Michael M.; Sandage, Allan
Data obtained in the 1950-1955 Palomar campaign for the discovery of classical novae in M81 are set out in detail. Positions and apparent B magnitudes are listed for the 23 novae that were found. There is modest evidence that the spatial distribution of the novae does not track the B brightness distribution of either the total light or the light b…
Post-Impulsive-Phase Acceleration in a Wide Range of Solar Longitudes
Kocharov, Leon; Torsti, Jarmo; Laitinen, Timo +1 more
We have analyzed five solar energetic particle (SEP) events observed aboard the SOHO spacecraft during 1996-1997. All events were associated with impulsive soft X-ray flares, Type II radio bursts and coronal mass ejections (CMEs). Most attention is concentrated on the SEP acceleration during the first 100 minutes after the flare impulsive phase, p…
Hubble Space Telescope observations of the black hole X-ray transient GRO J0422+32 near quiescence
Haswell, C. A.; Hynes, R. I.
We present HST/FOS ultraviolet and optical spectroscopy of the black hole X-ray transient GRO J0422+32 shortly before the system reached quiescence. We find that the accretion spectrum from 2500 to 9000 A can be very well fitted by a self-absorbed synchrotron model, with superposed H I and Mg II emission lines. The explanations that we suggest for…
The Search for Solar Gravity-Mode Oscillations: an Analysis Using ULYSSES Magnetic Field Data
Denison, David G. T.; Walden, Andrew T.
In 1995 Thomson, Maclennon, and Lanzerotti (TML) reported on work where they carried out a time-series analysis of energetic particle fluxes measured by Ulysses and Voyager 2 and concluded that solar g-mode oscillations had been detected. The approach is based on finding significant peaks in spectra using a statistical F-test. Using three sets of …
IRAS 03313+6058: an AGB star with 30 micron emission
Szczerba, R.; Jiang, B. W.; Deguchi, S.
This paper reports a detection of the 30 micron emission feature from the C-rich Asymptotic Giant Branch (AGB) star IRAS 03313+6058 based on the ISO-SWS observation. Modeling of the spectral energy distribution shows that this emission starts at about 20 micron and possibly extends to the limit (45 micron) of the observation. By assuming MgS as th…