Search Publications
Isotopic lithium abundances in five metal-poor disk stars
Lambert, D. L.; Nissen, P. E.; Primas, F. +1 more
High resolution (R =~ 110 000), very high S/N spectra centered on the 6707.8 Ä Li I line have been obtained with the ESO Coudé Echelle Spectrometer for five, metal-poor (-0.8 < [Fe/H] < -0.6) disk stars in the turnoff region of the HR-diagram. The instrumental and stellar atmospheric line broadening have been determined from two unblended ir…
Doppler imaging of stellar surface structure. XI. The super starspots on the K0 giant HD 12545: larger than the entire Sun
Strassmeier, K. G.
The active K0 giant HD 12545 is the star with the largest starspots ever observed. We report a record light-curve amplitude of 0\fm63 in V and 0\fm17 in V-I in January 1998. At the same time, HD 12545 was at its brightest magnitude since the discovery of its light variability in 1985. We present the first Doppler image of HD 12545 from observation…
ORFEUS spectroscopy of the O BT VI lines in symbiotic stars and the Raman scattering process
Schmutz, W.; Grewing, M.; Schild, H. +16 more
We present orfeus spectra of the O vi lambda lambda 1032,1038 emission lines in the symbiotic stars AG Dra, V1016 Cyg, RR Tel, CD-43(deg) 14304, AG Peg and Z And. The O vi emission lines can convert into broad and highly polarized emission lines at lambda 6825 and lambda 7082 in a Raman scattering process by neutral hydrogen. From a comparison of …
Interstellar dust and magnetic field at the boundaries of the Local Bubble. Analysis of polarimetric data in the light of HIPPARCOS parallaxes
Leroy, J. L.
Hipparcos stellar parallaxes have been used to reanalyse existing interstellar polarization data. The main results are: The nearest interstellar dust patches are at about 70 pc in some directions, in others beyond 150 pc. Thus the region devoid of dust, commonly identified with the Local Hot Bubble, is irregular in shape. The interstellar magnetic…
Two multiple-imaged Z = 4.05 galaxies in the cluster-lens Abell 2390
Smail, I.; Pelló, R.; Kneib, J. P. +8 more
We present the first results on the identification and study of very distant field galaxies in the core of cluster-lenses, using a selection criterium based on both lens modelling and photometric redshifts. We concentrate on two multiple-imaged sources at z = 4.05 in the cluster Abell 2390. The two objects presented in this paper, namely H3 (cusp …
Very cold dust in galaxies
Siebenmorgen, R.; Chini, R.; Krügel, E.
We present multi-filter far infrared photometry of active and inactive galaxies obtained with ISOPHOT. We find that the far infrared and submillimeter spectrum of the active galaxies can be described by a single modified black-body at a color temperature of 31.5 +/- 2.8 K. The ratio of infrared luminosity to gas mass, L_IR/M_gas, where the latter …
Water line emission in low-mass protostars
Liseau, R.; Ceccarelli, C.; White, G. +7 more
Using the Long Wavelength Specrometer aboard ISO, we have detected far infrared rotational H_2O emission lines in five low-mass young stellar objects in a survey of seven such sources. The total H_2O fluxes are well correlated with the 1.3 mm continuum fluxes, but - surprisingly - not with the SiO millimeter emission originating in the outflows, s…
ISO observations of the environment of the soft gamma-ray repeater SGR 1806-20
Chaty, S.; Fuchs, Y.; Claret, A. +3 more
Observations at near and mid-infrared wavelengths (1-18 mu m) of SGR 1806-20 suggest that it is associated with a cluster of giant massive stars which are enshrouded in a dense cloud of dust. The centre of the best sky position of the gamma-ray source (Hurley et al. \cite{hurley99}) lies on top of the dust cloud at only 7 arcsec ( ~ 0.5 pc at a di…
The HIPPARCOS HR diagram of nearby stars in the metallicity range: -1.0 < [Fe/H] < 0.3. A new constraint on the theory of stellar interiors and model atmospheres
Baglin, A.; Lebreton, Y.; Cayrel, R. +2 more
The Hipparcos mission has provided very high quality parallaxes of a sample of a hundred nearby disk stars, of spectral types F to K. In parallel, bolometric fluxes, effective temperatures, and accurate Fe/H ratios of many of these stars became available through infrared photometry and detailed spectroscopic analyses. These new accurate data allow…
AgapeZ1: a large amplification microlensing event or an odd variable star towards the inner bulge of M31
Giraud-Héraud, Y.; Bouquet, A.; Soucail, G. +14 more
AgapeZ1 is the brightest and the shortest duration microlensing candidate event found to date in the Agape experiment. It occurred only 42'' from the centre of M31 at RA=0(h) 42(m) 41.47(s) and Dec=41(deg) 16' 39.1'' (J2000). Our photometry shows that the half intensity duration of the event is 5.3 days and at maximum brightness its magnitude is R…