Search Publications
Molecular and dust features of 29 SiC carbon AGB stars
He, Jinhua; Yang, Xiaohong; Chen, Peisheng
We have reduced and analyzed the Infrared Space Observatory (ISO) Short-Wavelength Spectrometer (SWS) spectra of 29 infrared carbon stars with a silicon carbide feature at 11.30 µm, 17 of which have not been previously published. Absorption or emission features of C2, HCN, C2H2, C3 and silicon carb…
On the Hipparcos parallaxes of O stars
Kaper, L.; Schröder, S. E.; Brown, A. G. A. +1 more
We compare the absolute visual magnitude of the majority of bright O stars in the sky as predicted from their spectral type with the absolute magnitude calculated from their apparent magnitude and the Hipparcos parallax. We find that many stars appear to be much fainter than expected, up to five magnitudes. We find no evidence for a correlation be…
A young binary brown dwarf in the R-CrA star formation region
Demarco, R.; Martín, E. L.; Bouy, H. +5 more
We present imaging and spectroscopic observations with HST (WFPC2, ACS/HRC and STIS), VLT (FORS2) and Keck (HIRES) of the dM 8 ultra-cool dwarf
XMM-Newton spectral and timing analysis of the faint millisecond pulsars PSR J0751+1807 and PSR J1012+5307
Kramer, M.; Webb, N. A.; Barret, D. +3 more
We present XMM-Newton MOS imaging and PN timing data of the faint millisecond pulsars
New membership determination and proper motions of NGC 1817. Parametric and non-parametric approach
Jordi, C.; Balaguer-Núñez, L.; Galadí-Enríquez, D. +1 more
We have calculated proper motions and re-evaluated the membership probabilities of 810 stars in the area of two NGC objects, NGC 1817 and NGC 1807. We have obtained absolute proper motions from 25 plates in the reference system of the Tycho-2 Catalogue. The plates have a maximum epoch difference of 81 years; and they were taken with the double ast…
Axisymmetric dynamical models for SAURON and OASIS observations of NGC3377
Copin, Y.; Emsellem, E.; Cretton, N.
We present a unique set of nested stellar kinematical maps of NGC3377 obtained with the integral-field spectrographs OASIS and SAURON . We then construct general axisymmetric dynamical models for this galaxy, based on the Schwarzschild numerical orbit superposition technique applied to these complementary measurements. We show how these two datase…
Pox 186: An ultracompact galaxy with dominant ionized gas emission
Izotov, Y. I.; Papaderos, P.; Guseva, N. G. +2 more
We present a ground-based optical spectroscopic and HST U, V, I photometric study of the blue compact dwarf (BCD) galaxy Pox 186. It is found that the emission of the low-surface brightness (LSB) component in Pox 186 at radii ⪉3 arcsec (⪉270 pc in linear scale) is mainly gaseous in origin. We detect Hα emission out to radii as large as 6 arcsec. A…
Asiago eclipsing binaries program. I. V432 Aurigae
Munari, U.; Zwitter, T.; Sordo, R. +4 more
The orbit and physical parameters of the previously unsolved eclipsing binary V432 Aur, discovered by Hipparcos, have been derived with errors better than 1% from extensive Echelle spectroscopy and B, V photometry. Synthetic spectral analysis of both components has been performed, yielding Teff and log g in close agreement with the orbi…
The morphology of cometary X-ray emission
Dennerl, K.; Wegmann, R.; Lisse, C. M.
X-ray emission from comets is generated by charge exchange of heavy solar wind ions in a high ionization state with the neutral particles of the cometary coma. We use model calculations and theoretical considerations to study the morphology of the emission. The emission is located in a bowl-shaped region on the subsolar side of the nucleus. We der…
Effect of the electron density stratification on off-limb O VI line profiles: How large is the velocity distribution anisotropy in the solar corona?
Solanki, S. K.; Raouafi, N. -E.
Coronagraphic spectral observations carried out with UVCS on SoHO have shown that the velocity distribution in the solar corona is highly anisotropic. Here we examine the influence of the density stratification on the interpretation of such observations. In particular, we investigate the profiles of O VI lines emitted in the corona by employing an…