Search Publications
The Infrared Emission Features in the Spectrum of the Wolf-Rayet star WR 48a
Tielens, A. G. G. M.; Peeters, E.; Chiar, J. E.
We present the first detection of unidentified infrared (UIR) emission features at ~6.4 and 7.9 µm in the spectrum of the dusty WC8 Wolf-Rayet star WR 48a. Based on the H-deficient nature of WC stars, we attribute the emission features to large carbonaceous molecules or amorphous carbon dust grains in the circumstellar environment of WR 48a.…
XMM-Newton observations of the asynchronous polar BY Cam
Cropper, Mark; Ramsay, Gavin
We report observations of the asynchronous polar BY Cam made using XMM-Newton. We find evidence for two accretion regions which have significantly different spectra. In both regions we find evidence for hard X-ray emission from the post-shock flow while we observe a distinct soft X-ray blackbody component in only one. We detect two emission lines …
On the pulsation parallax of the variable star RR Lyr
Marconi, M.; Bono, G.; Caputo, F. +2 more
We show that a straightforward application of the predicted relation connecting the absolute K magnitude of fundamental RR Lyrae variables to their period and metal content, together with current evolutionary predictions on the mass and luminosity of Horizontal Branch stars, supply a distance estimate to the prototype star RR Lyr in close agreemen…
Active Nuclei and Star-forming Objects at z>2: Metallicities, Winds, and Formation Histories
Keel, William C.; Windhorst, Rogier A.; Pascarelle, Sebastian M. +2 more
We present near-infrared observations of the active galactic nuclei (AGNs) and star-forming objects in the field of the radio galaxy 53W002 at z=2.39. The star-forming objects are of special interest as candidate protogalactic objects. The 1.1-2.2 µm passbands sample the emitted-optical range at this redshift, providing new diagnostics of th…
Runaway Fragmentation of Sungrazing Comets Observed with the Solar and Heliospheric Observatory
Sekanina, Zdenek
The observed clustering of the Solar and Heliospheric Observatory (SOHO) sungrazing comets is a product of runaway fragmentation that occurs throughout their orbits about the Sun. Since the sungrazers in tight pairs occasionally appear simultaneously in the field of view of the SOHO coronagraphs, their offsets can be used to determine their separa…
High-Resolution Measurements of Intersystem Bands of Carbon Monoxide toward X Persei
Federman, S. R.; Lambert, David L.; Sheffer, Yaron
In an echelle spectrum of X Per acquired with the Space Telescope Imaging Spectrograph, we have identified individual rotational lines of 11 triplet-singlet (intersystem) absorption bands of 12CO. Four bands provide first detections for interstellar clouds. From a comparison with the ζ Oph sight line, we find that X Per is obscured by a…
Far-Infrared Spectroscopy of the HH 1/2 Outflow
Molinari, Sergio; Noriega-Crespo, Alberto
The HH 1/2 system has been observed with the two spectrometers on board the Infrared Space Observatory. Diffuse [C II] 158 µm emission indicates the presence of a photodissociation region (PDR), which is only in part due to the external far-UV (FUV) irradiation from the nearby Orion Nebula. Additional irradiation must originate locally, and …
Solar Particle Event with Exceptionally High 3He Enhancement in the Energy Range up to 50 MeV Nucleon-1
Torsti, J.; Kaiser, M. L.; Kocharov, L. +3 more
We have surveyed the 3He-rich solar particle events in the energy range of greater than 15 MeV nucleon-1 observed with the energetic particle instrument ERNE (the Energetic and Relativistic Nuclei and Electron experiment) on board the Solar and Heliospheric Observatory during 1999-2000. The survey reveals the exceptional even…
What Is Happening at Spectral Type F5 in Hyades F Stars?
Carpenter, Kenneth; Robinson, Richard; Böhm-Vitense, Erika +1 more
Aiming at a better understanding of the mechanisms heating the chromospheres, transition regions, and coronae of cool stars, we study ultraviolet, low-resolution Hubble Space Telescope/Space Telescope Imaging Spectrograph spectra of Hyades main-sequence F stars. We study the B-V dependence(s) of the chromospheric and transition layer emission line…
Astrometry and Near-Infrared Photometry of Neptune's Inner Satellites and Ring Arcs
Schneider, Glenn; Dumas, Christophe; Terrile, Richard J. +1 more
We report 1.87 µm photometry and astrometry of the inner satellites (Proteus, Larissa, Galatea, and Despina) and ring arcs of Neptune, obtained with the Hubble Space Telescope and its near-infrared camera NICMOS. From comparison with the Voyager data obtained at visible wavelengths, the small bodies orbiting within the ring region of Neptune…