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Water emission in NGC 1333-IRAS 4. The physical structure of the envelope
Maret, S.; Ceccarelli, C.; Caux, E. +2 more
We report ISO-LWS far infrared observations of CO, water and oxygen lines towards the protobinary system IRAS 4 in the NGC 1333 cloud. We detected several water, OH, CO rotational lines, and two [OI] and [CII] fine structure lines. Given the relatively poor spectral and spatial resolution of these observations, assessing the origin of the observed…
A new method for ISOCAM data reduction - II. Mid-infrared extragalactic source counts in the ELAIS Southern field
Pozzi, F.; Franceschini, A.; Serjeant, S. +5 more
We present the 15-µm extragalactic source counts from the Final Analysis Catalogue of the European Large Area ISO Survey (ELAIS) Southern hemisphere field S1, extracted using the Lari method. The large number of extragalactic sources (~350) detected over this area between about 0.5 and 100 mJy guarantee a high statistical significance of the…
The Lower Main Sequence and Mass Function of the Globular Cluster Messier 4
Rich, R. Michael; Gibson, Brad K.; Stetson, Peter B. +9 more
The deepest optical image ever in a globular star cluster, a Hubble Space Telescope 123 orbit exposure in a single field of Messier 4, was obtained in two filters (F606W, F814W) over a 10 week period in early 2001. A somewhat shallower image obtained in 1995 allowed us to select out cluster and field objects via their proper-motion displacement, r…
The Large-Scale Coronal Field Structure and Source Region Features for a Halo Coronal Mass Ejection
Shibata, K.; Kurokawa, H.; Yan, Yihua +2 more
On 1998 May 2 a class X1/3B flare occurred at 13:42 UT in NOAA Active Region 8210 near disk center, which was followed by a halo coronal mass ejection (CME) at 15:03 UT observed by SOHO/LASCO. Using the boundary element method (BEM) on a global potential model, we reconstruct the large-scale coronal field structure from a composite boundary by SOH…
Dust Grains in the Comae and Tails of Sungrazing Comets: Modeling of Their Mineralogical and Morphological Properties
Kimura, Hiroshi; Mann, Ingrid; Jessberger, Elmar K. +1 more
Observations of sungrazing comets, all of which belong to the Kreutz family, provide the opportunity of studying the properties of dust in the comae and tails of the comets. On the basis of available information on cometary and interplanetary dust as well as observations of dust in the tails of sungrazers, we model dust in sungrazing comets as flu…
Fundamental Properties and Distances of the Large Magellanic Cloud from Eclipsing Binaries. II. HV 982
Ribas, I.; Fitzpatrick, E. L.; Massa, D. +3 more
We have determined the distance to a second eclipsing binary (EB) system in the Large Magellanic Cloud, HV 982 (~B1 IV-V+~B1 IV-V). The measurement of the distance-among other properties of the system-is based on optical photometry and spectroscopy and space-based UV/optical spectrophotometry. The analysis combines the ``classical'' EB study of li…
Coronal density diagnostics with Helium-like triplets: CHANDRA-LETGS observations of Algol, Capella, Procyon, epsilon Eri, alpha Cen A&B, UX Ari, AD Leo, YY Gem, and HR 1099
Schmitt, J. H. M. M.; Burwitz, V.; Raassen, A. J. J. +5 more
We present an analysis of ten cool stars (Algol, Capella, Procyon, epsilon Eri, alpha Cen A&B, UX Ari, AD Leo, YY Gem, and HR 1099) observed with the Low Energy Transmission Grating Spectrometer (LETGS) on board the Chandra X-ray Observatory. This sample contains all cools stars observed with the LETGS presently available to us with integratio…
Asteroids as calibration standards in the thermal infrared for space observatories
Müller, T. G.; Lagerros, J. S. V.
Asteroids have been used extensively as calibration sources for the Infrared Space Observatory (ISO) and are planned to be used by future groundbased, airborne and space-based projects in the thermal infrared (IR) and in the sub-millimetre. We summarize the general IR observational parameters with a focus on space observatories and discuss brightn…
The ages of the globular clusters M 71 and 47 Tuc from Strömgren uvby photometry. Evidence for high ages
Grundahl, F.; Stetson, P. B.; Andersen, M. I.
New uvby CCD photometry for the fairly metal-rich globular clusters M 71 (NGC 6838) and 47 Tuc (NGC 104) is presented. We derive the cluster distances using a sample of field subdwarfs with metallicities determined from uvby photometry and accurate parallaxes from the Hipparcos mission. The biases associated with the main-sequence fitting techniqu…
The Distance Scale for Classical Cepheid Variables
Turner, David G.; Burke, James F.
New radii, derived from a modified version of the Baade-Wesselink (BW) method that is tied to published KHG narrowband spectrophotometry, are presented for 13 bright Cepheids. The data yield a best-fitting period-radius relation given by log<R/Rsolar>=1.071(+/-0.025)+0.747(+/- 0.028)logP0. In combination with other high…