Search Publications
Vertical motion and expansion of the Gould Belt
Comerón, F.
The kinematics of the Gould Belt is considered taking into account its orientation in space and the motions of its member stars parallel and perpendicular to the galactic plane. An analysis of Hipparcos data for these stars, complemented with published radial velocities, shows that there is a mild gradient along the galactic plane in the velocity …
ISO spectroscopy of shocked gas in the vicinity of T Tauri
Spinoglio, L.; van Dishoeck, E. F.; Tielens, A. G. G. M. +2 more
We present the results of ISO SWS and LWS spectroscopy of the young binary system T Tau. The spectrum shows absorption features due to H_2O ice, CO_2 ice, gas-phase CO and amorphous silicate dust, which we attribute to the envelope of T Tau S. We derive an extinction of A_V = 17.4m +/- 0.6m towards this source. Detected emission lines from H i ari…
ISO. Monitoring the mass loss of a very late Helium flash star
Blommaert, J. A. D. L.; Asplund, M.; Kimeswenger, S. +3 more
We present ISOCAM observations of Sakurai's object (V4334 Sgr) covering the wavelength range of 4 to 15 mu m in seven filters. The photometry shows that in the period from February 1997 to February 1998 the flux over the whole wavelength range has increased by a factor of about ten. Combined with ground-based data we conclude that this increase is…
New Zr II oscillator strengths and the zirconium conflict in the HgMn star chi LUPI
Leckrone, D. S.; Sikström, C. M.; Lundberg, H. +4 more
Lifetimes on the sub-nanosecond scale for the levels v(2) D_{3/2}, v(2) F_{3/2} and v(2) F_{5/2} in the 4d5s5p configuration in Zr II have been measured, using the method of laser-induced fluorescence. Combined with branching fractions obtained with the Lund Ultraviolet (UV) Fourier Transform Spectrometer (FTS), experimental oscillator strengths h…
Center-to-limb variation of the solar oscillation. New results from MDI data
Schmidt, W.; Stix, M.; Wöhl, H.
{Using 17 hours of full-disk MDI Doppler data we have investigated the center-to-limb variation of the oscillatory wave spectrum of the solar photosphere. Power distributions in the k_hnu -plane are calculated for fields of 20(deg) x 20(deg) on the Sun, centered at every 10(deg) heliographic latitude. From the center-to-limb variation of the power…
The ``Papillon'' nebula: a compact H bt II blob in the LMC resolved by it HST
Heydari-Malayeri, M.; Charmandaris, V.; Zinnecker, H. +2 more
We present high spatial resolution HST imaging of the LMC compact {H ii} region N159-5. This high excitation blob is revealed to be a ``papillon'' or butterfly-shaped ionized nebula with the ``wings'' separated by { ~ },2''.3 (0.6 pc). Two subarcsecond features resembling a ``smoke ring'' and a ``globule'' are detected in the wings, the origin of …
The absolute magnitudes of RR Lyrae stars from BT HIPPARCOS parallaxes parallaxes
Salaris, M.; Groenewegen, M. A. T.
Using the method of ``reduced parallaxes'' for the Halo RR Lyrae stars in the hipparcos catalogue we derive a zero point of 0.77 +/- 0.26 mag for an assumed slope of 0.18 in the M_V-[Fe/H] relation. This is 0.28 magnitude brighter than the value Fernley et al. (1998a) derived by employing the method of statistical parallax for the identical sample…
Infrared spectra of young stars in Chamaeleon
Henning, Th.; Lemke, D.; Pfau, W. +2 more
We present infrared spectra covering the wavelength ranges 3.1-5.0 mu m and 5.8-11.6 mu m for 9 young stars located in the Chamaeleon I dark cloud. The spectra were taken with the spectrophotometer of ISO (ISOPHOT-S). The spectra of three stars which illuminate reflection nebulae are dominated by the series of strong emission features generally as…
ISO-SWS spectroscopy of IC443 and the origin of the IRAS 12 and 25 MU M emission from radiative supernova remnants
Lutz, D.; Oliva, E.; Moorwood, A. F. M. +1 more
ISO-SWS spectral observations of the supernova remnant IC443 are presented. Like other radiative SNRs, this object is characterized by prominent line-emitting filaments and relatively strong IRAS 12 and 25 mu m emission which is commonly interpreted as thermal radiation from very small grains stochastically heated by collisions with the hot plasma…
A search for star formation in the translucent clouds MBM7 and MBM55
Schmitt, J. H. M. M.; Neuhäuser, R.; Caillault, J. -P. +3 more
The star formation capability of two molecular clouds at high galactic latitude ( | b | > 30(deg) ) is investigated. Possible pre-main sequence stars in and around the translucent clouds MBM7 and MBM55 have been identified via their X-ray emission by inspecting ROSAT All-Sky Survey observations of the clouds and environs and ROSAT pointed obser…