Search Publications
Excitation of Far-Infrared Lines of OH and Maser Pumping Efficiency in Circumstellar Envelopes
Bujarrabal, V.; Nguyen-Q-Rieu; Le Bertre, T. +3 more
We present the results obtained with a radiative transfer model to investigate the excitation of OH molecules. Maser pumping efficiencies are estimated from the model and compared to the value calculated using recent OH far-infrared (FIR) observations with ISO and OH maser data.
Calibration of the Classical Cepheid Period-Luminosity Relation from HIPPARCOS Data
Luri, X.; Figueras, F.; Torra, J. +3 more
The calibration of the classical Cepheid Period-Luminosity (PL) relation is a fundamental step for the determination of the cosmic distance scale. In this paper a calibration obtained from Hipparcos data is presented and used to estimate the LMC distance modulus. A value of 18.35m ± 0.13 is obtained.
Spectroscopic Survey of δ SCT Stars
Solano, E.; Pintado, O. I.
The methods used to derive effective temperatures, projected rotational velocities and surface gravities of a sample of low and high-amplitude δ Sct stars are presented here. Effective temperatures were derived using Hα and Hβ line profiles whereas rotational velocities were calculated following the method described in Solano & Fernley (1997).…
Protostars and Protoplanetary Disks
Boss, A. P.
Observations of the Dust Around Evolved Stars
Walker, H. J.; Richards, P. J.; Heinrichsen, I.
ISOPHOT has been used to obtain low resolution spectra from 2.5µm to 5µm and 5.8µm to 11.6µm and multi-aperture photometry at 60µm of several evolved stars; oxygen-rich and carbon-rich (including the peculiar carbon-rich stars R CrB and RY Sgr). R CrB was observed early in the ISO mission, 3 weeks after it had been at minimum light. Another spectr…
Far-Infrared CO Rotational Lines in the Orion Molecular Cloud
Cernicharo, J.; González-Alfonso, E.; Lefloch, B. +3 more
We present a high signal-to-noise grating spectrum between 43-196.9 µm of the Orion molecular cloud towards the massive star-forming region IRc2, obtained with the Long Wavelength Spectrometer (LWS) on board the Infrared Space Observatory (ISO). CO lines up to J=20-19 have been detected around Orion-IRc2, while in the central position higher…
ISO SWS Spectroscopy of Proto-Planetary Nebulae
Volk, Kevin; Kwok, Sun; Hrivnak, Bruce J.
We are obtaining low- (SWS01) and medium-resolution (SWS06) spectra of PPNe to investigate spectral features arising in these transitional objects. Three sources with the 21 µm feature have been confirmed, one new source found, and evidence of some substructure seen.
Observation of Microstructures in Planetary Nebulae
Walsh, J. R.; Dudziak, G.
HST images of 5 Planetary nebulae showing small scale structures have been retrieved from the archives. For two PNe, NTT images were also available, and a double channel deconvolution technique applied to combine them to the HST images. A very precise flux calibration was performed on the HST images. Bow shocks and ionization effects are likely de…
Infrared Emissions from Metals in Carbon Stars and M Giant
Ohnaka, K.; Tsuji, T.; Aoki, W.
Dust and Atomic Gas in Post-AGB Envelopes
Meixner, M.