Search Publications
Surface Brightness of Starbursts at Low and High Redshifts
Schneider, Donald P.; Weedman, Daniel W.; Wolovitz, Jeffrey B. +1 more
Observations in the rest-frame ultraviolet from various space missions are used to define the nearby starburst regions having the highest surface brightness on scales of several hundred parsecs. The bright limit is found to be 6 x 10^-16 ergs cm^-2 s^-1 Å^-1 arcsec^-2 for rest-frame wavelength of 1830 Å. Surface brightness in the brightest pixel i…
Ion acoustic-like waves observed by Ulysses near interplanetary shock waves in the three-dimensional heliosphere
Forsyth, R. J.; Neugebauer, M.; MacDowall, R. J. +2 more
The Ulysses spacecraft encountered 160 interplanetary shock waves between the time of its launch in October 1990 and the end of 1993 when it reached 48°S heliographic latitude. The onboard radio and plasma wave instrument observed many plasma waves associated with these shocks. Electrostatic waves at frequencies between the ion and electron plasma…
UV turn-off times of classical novae
Gallagher, J.; Orio, M.; Gonzalez-Riestra, R.
We present IUE spectra of classical novae obtained at least one year after the outburst. The UV luminosities are compared with the ROSAT\ observations and significant parameters of the systems. The turn-off times derived from the IUE data are in agreement with the ROSAT\ results, showing that most novae decline in bolometric luminosity 1-5 years a…
On the new lambda Bootis-type spectroscopic binary systems HD 84948 and HD 171948
Handler, G.; Garrido, R.; Heiter, U. +4 more
We report the discovery of two new lambda Bootis-type spectroscopic binary systems (HD 84948 and HD 171948). High resolution spectra were analyzed in order to derive abundances as well as astrophysical quantities. It resulted in extreme (HD 171948) and moderate (HD 84948) underabundances of Na, Mg, Si, Ca, Sc, Ti, Cr and Fe with respect to the Sun…
An extremely red r(1/4) galaxy in the test image of the Hubble Deep Field South
Ferguson, H. C.; Walker, A. R.; Treu, T. +14 more
We report the serendipitous discovery of an extremely red object in the Hubble Deep Field South (HDFS) Test NICMOS (Near Infrared Camera and Multi Object Spectrograph) field of view. The object is resolved in the NICMOS image and has a light profile very well described by an r(1/4) law with effective radius re=0farcs 20+/-0.05 and H_AB=…
Molecules of Non-Photospheric Origin in Red Giants and Supergiants Revealed by the ISO SWS
Ohnaka, K.; Yamamura, I.; Tsuji, T. +1 more
Overall SEDs based on ISO SWS observations show fair agreement with photospheric model predictions for red (super)giant stars. However, some details of molecular spectra cannot be explained by a photospheric origin. In particular, fine structure in the H2O 2.7 µm band can be clearly resolved by the SWS and is identified in an early M giant, whose …
Supra-Horizontal-Branch Stars and Population Gradients in the Galactic Center Globular Cluster NGC 6522
Rich, R. M.; King, I. R.; Paresce, F. +3 more
We have imaged the core of NGC 6522 and an adjacent field 1' north in the U and B passbands using the (pre-COSTAR) HST Planetary Camera. We find 13 stars located 1.5 mag above the horizontal branch. These supra-horizontal-branch (SHB) stars have not been noted previously in NGC 6522, although they occur in other globular clusters. The SHB stars' r…
A Lower Limit to the Distance of High-Velocity Cloud Complex H
Wakker, Bart; van Woerden, Hugo; de Boer, Klaas S. +1 more
We derive a lower limit for the distance of the high-velocity cloud (HVC) complex H, which is a structure covering 480 square degrees on the sky and is centered on l = 131°, b = 1°. Considering the uncertainties in the derivation of stellar distances, we find that the distance to the HVC is certainly larger than 3.4 kpc, probably larger than 5 kpc…
An estimation of the mass of asteroid 20-Massalia derived from the HIPPARCOS minor planets data
Bange, Jeff
The ESA astrometry satellite Hipparcos has observed a set of 48 minor planets between 1989 and 1993. A close encounter between 20-Massalia and 44-Nysa, both planets observed by Hipparcos, enabled us to obtain a value for the mass of 20-Massalia. Due to another close approach with the large asteroid 4-Vesta, the value we obtained (2.42 +/- 0.41 10(…
Hipparcos Observations of Hydrogen-deficient Carbon Stars *
Cottrell, P. L.; Lawson, W. A.
Parallax measurements for 21 hydrogen-deficient carbon stars have been made by the Hipparcos satellite. These stars include most of the brighter R Coronae Borealis (RCB) variables, other cool hydrogen-deficient carbon (HdC) stars, and several higher-T eff extreme helium (eHe) stars. Most of these stars have either negative or statistica…