Published in ScienceOpen Astronomy & Astrophysics
We present J, H, CH 4 short (1.578 μ m), CH 4 long (1.652 μ m) and K s-band images of the dust ring around the 10 Myr old star HR 4796 A obtained using the Near Infrared Coronagraphic Imager (NICI) on the Gemini-South 8.1 m Telescope. Our images clearly show for the first time the position of the star relative to its circumstellar ring thanks to NI...
Published in ScienceOpen Astronomy & Astrophysics
We present resolved NACO photometry of the close binary AB Dor B in H-and Ks- band. AB Dor B is itself known to be a wide binary companion to AB Dor A, which in turn has a very low-mass close companion named AB Dor C. These four known components make up the young and dynamically interesting system AB Dor, which will likely become a benchmark system...
Published in ScienceOpen Astronomy & Astrophysics
Nine bright O-rich Mira stars and five semiregular variable cool M giants have been observed with the Infrared and Optical Telescope Array (IOTA) interferometer in both K0 ($2.15 lm) and L0 ($3.8 lm) broadband filters, in most cases at very close variability phases. All of the sample Mira stars and four of the semiregular M giants show strong incre...
Published in ScienceOpen Astronomy & Astrophysics
We report the discovery in the ISO/SWS spectrum of the post-AGB star HR 4049 of emission bands due to 17 O and 18 O isotopes locked up in CO 2 molecules. It is the first time these isotopomers are detected outside the solar system. Isotopic ratios derived in the optically thin limit are as low as 16 O/17 O $= 8.3\ pm 2.3$ and 16 O/$^18\ rm O= 6.9\ ...
Published in ScienceOpen Astronomy & Astrophysics
Aims. To study the nature of Bulge AGB stars and in particular their circumstellar dust, we have analysed mid-infrared spectra obtained with the ISOCAM CVF spectrometer in three Bulge fields. Methods. The ISOCAM 5-16.5$\ mu $ m CVF spectra were obtained as part of the ISOGAL infrared survey of the inner Galaxy. A classification of the shape of the ...
Published in ScienceOpen Astronomy & Astrophysics
Context. Photodissociation regions (PDRs) contain a large portion of all of the interstellar matter in galaxies. Classical examples include the boundaries between ionized regions and molecular clouds in regions of massive star-formation, marking the point where all of the photons that are energetic enough to ionize hydrogen have been absorbed. Aims...
Published in ScienceOpen Astronomy & Astrophysics
The large main-belt asteroid (216) Kleopatra has been for long suspected to be a binary object, mainly due to its large lightcurve amplitude. However, recent observations suggest that it is a single" bone-shaped" or bi-lobated body (Ostro et al. 2000; Tanga et al. 2001). We present results obtained from ground-based adaptive optics observations, an...
Published in ScienceOpen Astronomy & Astrophysics
Context. Modeling of pre-main sequence (PMS) stars through asteroseismology of PMS p-mode pulsators has only recently become possible, and spacebased photometry is one of the important sources of data for these efforts. We present precise photometry of the pulsating Herbig Ae star HD 142666 obtained in two consecutive years with the MOST (Microvari...
Published in ScienceOpen Astronomy & Astrophysics
We analyze ISO archive data of the nearby bright emission-line star 51 Oph, previously classified as a proto-planetary system similar to $\ beta $ Pic. The infrared spectrum reveals the presence of gas-phase emission bands of hot (~ 850 K) CO, CO 2, H 2 O and NO. In addition to this, partially crystalline silicate dust is present. The solid-state b...
Published in ScienceOpen Astronomy & Astrophysics
We report on the analysis of high-precision space-based photometry of the roAp (rapidly oscillating Ap) stars HD 9289, HD 99563, and HD 134214. All three stars were observed by the MOST satellite for more than 25 days, allowing unprecedented views of their pulsation. We find previously unknown candidate frequencies in all three stars. We establish ...
