Search Publications

On the Reliability of Ring Diagram Analysis
DOI: 10.1086/305819 Bibcode: 1998ApJ...501..408G

Chou, Dean-Yi; Gonzalez Hernandez, I.; Patron, J. +1 more

A comparison between the results of applying a ring diagram analysis to two data sets is described in order to check the quality of the two sets and the reliability of the method. The series used have been obtained with two different helioseismological instruments with the same spatial resolution. A section of 30 × 30 deg2 about the disk center ha…

1998 The Astrophysical Journal
SOHO 7
HST/WFPC2 observation of the core of M 3: Blue objects and the position of the radio source
Bibcode: 1998A&A...332...93L

Ferraro, F. R.; Fusi Pecci, F.; Laget, M. +1 more

HST/WFPC2 images of the central part of the globular cluster M 3 (NGC 5272) in UV (F255W), U (F336W), V (F555W) and I (F814W) are used to search for faint blue stars down to an UV magnitude slightly below the turnoff level. Three low-luminosity blue stars are found in the PC1 field of view; two are new detections. All are within ~ 10arcsec from th…

1998 Astronomy and Astrophysics
eHST 7
Cassini Plasma Spectrometer Investigation
DOI: 10.1029/GM102p0237 Bibcode: 1998GMS...102..237Y

Coates, A. J.; Grande, M.; Johnson, R. E. +22 more

Cassini/Huygens is a joint project of NASA and the European Space Agency designed to explore the Saturnian system in depth during its four-year mission. Cassini, the orbiter spacecraft, will carry twelve hardware investigations while Huygens, the Titan atmospheric probe, will carry an additional six. The Cassini Plasma Spectrometer (CAPS), one of …

1998 Geophysical Monograph Series
Cassini 7
Insights into the accretion flow in QS Telescopii (RE1938-461) from HST observations
Bibcode: 1998A&A...329..571D

Gänsicke, B. T.; de Martino, D.; Mason, K. O. +3 more

We present HST/FOS observations of the polar QS Tel (RE1938-461) revealing new details in its 140min UV orbital variability. A colour-dependent continuum orbital modulation as well as a narrow dip in its light curve, occurring at the same orbital phases as the one detected in the EUVE band, are observed. Their spectral dependence allows us to iden…

1998 Astronomy and Astrophysics
eHST 7
PDRS and Shocks in S106 IR and CEP a East
DOI: 10.1023/A:1001158717379 Bibcode: 1998Ap&SS.255...69V

Waters, L. B. F. M.; Tielens, A. G. G. M.; van den Ancker, M. E. +1 more

We present SWS grating scans of pure H2 rotational lines, as well as several infrared fine-structure lines for two embedded Young Stellar Objects, S106 IR and Cep A East. Excitation temperatures and masses were derived from the low-lying pure rotational levels of H2 and are 490 and 740 K and 0.04 and 0.007 M⊙ for S106 and Cep A, respectively. The …

1998 Astrophysics and Space Science
ISO 7
On the use of HIPPARCOS data for the determination of astrometric positions of outer planets
Bibcode: 1998A&A...335.1111F

Fienga, Agnes

We investigated the improvement of observed astrometric positions of outer planets by use of Hipparcos Catalogue stars and satellite measurements. Positions of Jupiter from photographic plates were obtained, indirectly, from measurements of the Galilean satellites, using the G5 ephemerides of Bureau des Longitudes. The use of Hipparcos data in the…

1998 Astronomy and Astrophysics
Hipparcos 7
Fe II emission lines in the UV spectrum of Sirius-A and VEGA
DOI: 10.48550/arXiv.astro-ph/9803127 Bibcode: 1998A&A...334..633V

Ferlet, R.; Vidal-Madjar, A.; Lanz, T. +4 more

We present high-quality HST/GHRS spectra in the Hydrogen Lalpha spectral region of Vega and Sirius-A. Thanks to the signal-to-noise ratio achieved in these observations and to the similarity of the two spectra, we found clear evidence of emission features in the low flux region, lambda lambda 1190-1222 Angstroms. These emission lines can be attrib…

1998 Astronomy and Astrophysics
eHST 7
The IUE Spectrum, Electron Density, and Terminal Wind Velocity of the ``O VI Sequence'' Planetary Nebula NGC 5315
DOI: 10.1086/306281 Bibcode: 1998ApJ...506..773F

Feibelman, Walter A.

Extensive archival and new IUE data obtained during the last (19th) year episode of the ``O VI sequence'' planetary nebula NGC 5315 and its central star have been analyzed. A large number of high-excitation emission lines have been identified, and their fluxes were determined. These yield electron densities from C III], Si III], and N III], and te…

1998 The Astrophysical Journal
IUE 7
Ulysses observations of field-perpendicular plasma flows in the Jovian magnetosphere: comparison of ExB velocity vectors derived from energetic ion and thermal electron data
DOI: 10.1016/S0032-0633(98)00084-1 Bibcode: 1998P&SS...47..205L

Balogh, A.; McComas, D. J.; Dunlop, M. W. +4 more

The ExB velocity vectors which correspond to the field-perpendicular flow of the low-energy plasma have been independently derived for the Ulysses flyby of Jupiter using energetic ion and thermal electron data. In this paper these measurements are compared. It is shown that reasonable quantitative agreement exists during the prenoon inbound pass, …

1998 Planetary and Space Science
Ulysses 7
The O V 1213.9 Angstroms forbidden line in the quiet Sun
Bibcode: 1998A&A...340L..15P

Curdt, W.; Mathioudakis, M.; Keenan, F. P. +2 more

We present the first unambiguous detection of the O v 1213.9 Angstrom (2s(2) (1) S_0 -> 2s2p (3) P_2) forbidden line in the solar spectrum, using observations obtained with the SUMER instrument on board SOHO. The wavelength separation of the forbidden to the (2s(2) (1) S_0 -> 2s2p (3) P_1) intercombination line at 1218.35 Angstroms is 4.5+/-…

1998 Astronomy and Astrophysics
SOHO 7