Search Publications
PAH's and Crystalline Silicates in Planetary Nebulae
Beintema, D. A.
An overview is given of the PAH and crystalline silicate emissions seen in the SWS guaranteed-time programme on planetary nebulae. Of the 9 objects on which good continuum measurements were obtained above 29 µm, 7 show evidence of olivine emission at 33.5 µm. PAH emission is seen in 5 of these objects, 3 objects show both PAH's and olivines. The p…
The art of fitting p-mode spectra. II. Leakage and noise covariance matrices
Appourchaux, T.; Gizon, L.; Rabello-Soares, M. -C.
In Part I we have developed a theory for fitting p-mode Fourier spectra assuming that these spectra have a multi-normal distribution. We showed, using Monte-Carlo simulations, how one can obtain p-mode parameters using ``Maximum Likelihood Estimators". In this article, hereafter Part II, we show how to use the theory developed in Part I for fittin…
Molecules in AGB Stars Observed with ISO
Cernicharo, J.
I present in this review the recent results obtained with ISO concerning gas phase molecules in evolved stars. The near, medium and far-infrared spectrum of C-rich and O-rich stars can provide a very important information on the molecular content of these objects. Detailed models for the envelopes of AGB stars are also presented. I also report the…
F, G and K stars in the ROSAT all-sky survey. I. Photometry
Pasquini, L.; Krautter, J.; Cutispoto, G. +2 more
We present accurate BV(RI)_c photometry for a sample of F, G and K stars detected in selected areas of the ROSAT all-sky survey (RASS). We have used the photometry, in addition to low-resolution spectroscopy, to estimate spectral classifications, distances and X-ray luminosities. The log (L_X / L_V) in the sample lies below -2. Although the sample…
ISO Observations of Wolf-Rayet Dust Shells
Morris, P. W.; van der Hucht, K. A.; Williams, P. M.
Observations of circumstellar dust clouds of Wolf-Rayet stars made with the Short Wavelength Spectrometer on ISO reveal a subtle variety of spectral energy distributions not evident from ground-based observations. The modelling of these using the radiative transfer code "Dusty" by Ivezić, Nenkova & Elitzur is reported. The results are used to …
The Calibration of the Hubble Space Telescope Kuiper Belt Object Search: Setting the Record Straight
Stern, S. Alan; Levison, Harold F.; Tamblyn, Peter +2 more
The limiting magnitude of the Hubble Space Telescope (HST) data set used by Cochran and coworkers in 1995 to detect small objects in the Kuiper belt is reevaluated, and the methods used are described in detail. It is shown, by implanting artificial objects in the original HST images and rereducing the images using our original algorithm, that the …
Evolutionary status and age spread in the young LMC cluster NGC 1850A
Caloi, V.; Cassatella, A.
IUE spectra have been obtained for 15 members of the very young LMC cluster NGC 1850A. The extinction law toward the cluster is similar to the one generally accepted for the 30 Dor region. We derive the effective temperatures and bolometric luminosities to estimate the age and mass for each star. An age spread of 2 to 10 Myr is estimated, suggesti…
A Photometric and Spectrophotometric Study of MR Cygni
Hubeny, I.; Linnell, A. P.; Etzel, P. B. +1 more
A self-consistent, physically accurate program suite has been used in an accurate simulation of new spectroscopy and photometry of MR Cygni. Analysis of both the spectroscopic and photometric data used spectrum synthesis techniques and a synthetic photometry augmentation of a light synthesis program package. The theoretical light curves closely fi…
UVCS/SOHO: The First Two Years
Cranmer, S. R.; Noci, G.; Kohl, J. L.
The SOHO Ultraviolet Coronagraph Spectrometer (UVCS/SOHO) has observed the extended solar corona between 1 and 10 R· for more than two years. We review spectroscopic and polarimetric measurements made in coronal holes, equatorial streamers, and coronal mass ejections, as well as selected non-solar targets. UVCS/SOHO has provided a great amount of …
Compact HII regions in the Large Magellanic Cloud observed by ISO
Comeron, F.; Claes, P.
We present ISOCAM observations of five fields in the Large Magellanic Cloud centered on IRAS point sources with colors of ultracompact HII regions. Three bright sources of parsec or subparsec size, with luminosities consistent with being embedded O stars, are detected at 15 mu m in two fields belonging to the HII region N 159. Using published high…