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Astrometric and Light-Travel Time Orbits to Detect Low-Mass Companions: A Case Study of the Eclipsing System R Canis Majoris
Guinan, Edward F.; Arenou, Frédéric; Ribas, Ignasi
We discuss a method to determine orbital properties and masses of low-mass bodies orbiting eclipsing binaries. The analysis combines long-term eclipse timing modulations (the light-travel time [LTT] effect) with short-term, high-accuracy astrometry. As an illustration of the method, the results of a comprehensive study of Hipparcos astrometry and …
Keck Adaptive Optics Images of Uranus and Its Rings
de Pater, Imke; Roe, H. G.; Max, C. E. +3 more
We present adaptive optic images of Uranus obtained with the 10-m W. M. Keck II telescope in June 2000, at wavelengths between 1 and 2.4 µm. The angular resolution of the images is ∼0.06-0.09″. We identified eight small cloud features on Uranus's disk, four of which were in the northern hemisphere. The latter features are ∼1000-2000 km in ex…
Arrival times of Flare/Halo CME associated shocks at the Earth: comparison of the predictions of three numerical models with these observations
Dryer, M.; Smith, Z.; Fry, C. D. +7 more
The arrival times at L1 of eleven travelling shocks associated both with X-ray flaring and with halo CMEs recorded aboard SOHO/LASCO have been considered. Close to the Sun the velocities of these events were estimated using either Type II radio records or CME speeds. Close to the Earth the shocks were detected in the data of various solar wind pla…
NICMOS Snapshot Survey of Damped Lyα Quasars
Malkan, Matthew A.; Colbert, James W.
We image 19 quasars with 22 damped Lyα systems (DLAs) using the F160W filter and the Near-Infrared Camera and Multi-Object Spectrograph on board the Hubble Space Telescope in both direct and coronagraphic modes. We reach 5 σ detection limits of ~H=22 in the majority of our images. We compare our observations to the observed Lyman break population …
Infrared Space Observatory Investigates the Nature of Extremely Red Hard X-Ray Sources Responsible for the X-Ray Background
Elbaz, D.; Franceschini, A.; Flores, H. +3 more
We analyze very deep X-ray and mid-IR surveys in common areas of the Lockman Hole and the Hubble Deep Field-North (HDF-N) to study the sources of the X-ray background (XRB) and to test the standard obscured accretion paradigm. Observations with XMM-Newton and Infrared Space Observatory (ISO) of a substantial area in Lockman are particularly import…
Solar eruptions and long wavelength radio bursts: The 1997 May 12 event
Kaiser, M. L.; Gopalswamy, N.
We report on the cause of the 1997 May 12 type II bursts observed by ground based and space-based radio instruments. We estimate the fast mode speed in the corona as a function of heliocentric distance to identify the regions where fast mode shocks can be driven by CMEs. We find that both the coronal and the interplanetary type II bursts can be ex…
Multiwavelength Observations of the Peculiar Planetary Nebula IC 2149
López, J. A.; Torrelles, J. M.; Miranda, L. F. +4 more
We report high- and low-dispersion spectroscopy, optical imaging, and high-resolution Very Large Array-A λ3.6 cm continuum observations of the peculiar planetary nebula IC 2149. These observations show that ``bipolar'' is a suitable morphological classification for IC 2149. Most nebular material is concentrated in a knotty, bright ring seen edge-o…
The ISO-LWS map of the Serpens cloud core. II. The line spectra
Liseau, R.; Larsson, B.; Men'shchikov, A. B.
We present spectrophotometric ISO imaging with the LWS and the CAM-CVF of the Serpens molecular cloud core. The LWS map is centred on the far infrared and submillimetre source FIRS 1/SMM 1 and its size is 8',x 8'. The fine structure line emission in [O I] 63 mu m and [C II] 157 mu m is extended on the arcminute scale and can …
Methane Abundance on Titan, Measured by the Space Telescope Imaging Spectrograph
Lorenz, Ralph D.; Lemmon, Mark T.; Smith, Peter H.
Although methane is the dominant absorber in Titan's reflection spectrum, the amount of methane in the atmosphere has only been determined to an order of magnitude. We analyzed spectra from the Space Telescope Imaging Spectrograph, looking at both a bright surface region (700-km radius) and a dark surface region. The difference between the spectra…
The highly variable X-ray spectrum of the luminous Seyfert 1 galaxy 1H 0419-577
O'Brien, P. T.; Reeves, J. N.; Page, K. L. +1 more
An XMM-Newton observation of the luminous Seyfert 1 galaxy 1H 0419-577 is presented. We find that the spectrum is well fitted by a power law of canonical slope and three blackbody components (to model the strong soft excess). The XMM-Newton data are compared and contrasted with observations by ROSAT in 1992 and by ASCA and BeppoSAX in 1996. We fin…