Search Publications
Missions
Journals
Publication Years
Modeling of PMS Ae/Fe stars using UV spectra
Blondel, P. F. C.; Djie, H. R. E. Tjin A.
Context: .Spectral classification of AeFe stars, based on visual observations, may lead to ambiguous conclusions.
Aims: . We aim to reduce these ambiguities by using UV spectra for the classification of these stars, because the rise of the continuum in the UV is highly sensitive to the stellar spectral type of A/F-type stars.
Methods: . …
A large cloud outburst at Titan's south pole
Brown, Michael E.; Bouchez, Antonin H.; Roe, Henry G. +1 more
Images of Titan acquired over five nights in October 2004 using the adaptive optics system at the Keck Observatory show dramatic increases in tropospheric cloud activity at the south pole compared with all other images of Titan clouds to date. During this time, Titan's south polar clouds brightened to more than 18 times their typical values. The C…
Neon and Oxygen Abundances in M33
Massey, Philip; Garnett, Donald R.; Jacoby, George +1 more
We present new spectroscopic observations of 13 H II regions in the Local Group spiral galaxy M33. The regions observed range from 1 to 7 kpc in distance from the nucleus. Of the 13 H II regions observed, the [O III] λ4363 line was detected in six regions. Electron temperatures were thus able to be determined directly from the spectra using the [O…
XMM-Newton spectroscopy of the cluster of galaxies 2A 0335+096
Kaastra, J. S.; de Plaa, J.; Verbunt, F. +5 more
We present here the results of a deep (130 ks) XMM-Newton observation of the cluster of galaxies 2A 0335+096. The deep exposure allows us to study in detail its temperature structure and its elemental abundances. We fit three different thermal models and find that the multi-temperature wdem model fits our data best. We find that the abundance stru…
Radio science investigations by VeRa onboard the Venus Express spacecraft
Pätzold, M.; Bird, M. K.; Imamura, T. +10 more
The Venus Express Radio Science Experiment (VeRa) uses radio signals at wavelengths of 3.6 and 13 cm ("X"- and "S"-band, respectively) to investigate the Venus surface, neutral atmosphere, ionosphere, and gravity field, as well as the interplanetary medium. An ultrastable oscillator (USO) provides a high quality onboard reference frequency source;…
Continuum γ-ray emission from light dark matter positrons and electrons
Schanne, S.; Sizun, P.; Cassé, M.
The annihilation of light dark matter was recently advocated as a possible explanation of the large positron injection rate at the Galactic center deduced from observations by the SPI spectrometer aboard INTEGRAL. The modelling of internal Bremsstrahlung and in-flight annihilation radiations associated to this process drastically reduced the mass …
Coronal Observations of CMEs. Report of Working Group A
Schwenn, R.; Pick, M.; Reiner, M. +15 more
CMEs have been observed for over 30 years with a wide variety of instruments. It is now possible to derive detailed and quantitative information on CME morphology, velocity, acceleration and mass. Flares associated with CMEs are observed in X-rays, and several different radio signatures are also seen. Optical and UV spectra of CMEs both on the dis…
SMART-1 mission to the Moon: Status, first results and goals
Schmidt, W.; Grande, M.; Keller, H. U. +19 more
We present the first results from SMART-1's science and technology payload. SMART-1 is Europe's first lunar mission and will provide some significant advances to many issues currently active in lunar science, such as our understanding of lunar origin and evolution. The mission also contributes a step in developing an international program of lunar…
HD3651B: the first directly imaged brown dwarf companion of an exoplanet host star
Mazeh, T.; Neuhäuser, R.; Mugrauer, M. +1 more
In the course of our ongoing multiplicity study of exoplanet host stars we detected a faint companion located at ~43arcsec (480au physical projected separation) north-west of its primary - the exoplanet host star HD3651 at 11pc. The companion, HD3651B, clearly shares the proper motion of the exoplanet host star in our four images, obtained with th…
Outflows from Massive Young Stellar Objects as Seen with the Infrared Array Camera
Smith, Howard A.; Marengo, M.; Hora, J. L. +1 more
The bipolar outflow from the massive star-forming cluster in DR 21 is one of the most powerful known, and in IRAC images the outflow stands out by virtue of its brightness at 4.5 µm (band 2). Indeed, IRAC images of many Galactic and extragalactic star formation regions feature prominent band 2 morphologies. We have analyzed archival ISO SWS …