Search Publications
Missions
Journals
Publication Years
The Low- and Intermediate-Mass Stellar Population in the Small Magellanic Cloud: The Central Stars of Planetary Nebulae
Villaver, Eva; Shaw, Richard A.; Stanghellini, Letizia
We present a study on the central stars (CSs) of planetary nebulae (PNs) observed in the Small Magellanic Cloud (SMC) with the Space Telescope Imaging Spectrograph (STIS) instrument on board the Hubble Space Telescope (HST). The stellar magnitudes have been measured using broadband photometry, and Zanstra analysis of the nebulae provided the stell…
The Inner Ring of NGC 4736: Star Formation on a Resonant Pattern
Muñoz-Tuñón, Casiana; Aguerri, J. Alfonso L.; Caon, Nicola
We revise the explanation for the ``expanding H II regions ring'' of NGC 4736. From the analysis of long-slit spectra, we identify structures within the emission region previously reported in the literature as a single ring (former parameters: R~47", FWHM=21"). The H II ring is located at 35" (1.12 kpc) galactocentric distance, and its thickness i…
Pulsation Phase-Dependent Dust Shell Models for Oxygen-rich Asymptotic Giant Branch Stars
Suh, Kyung-Won
We investigate the spectral energy distributions (SEDs) of oxygen-rich asymptotic giant branch (AGB) stars at different pulsation phases using infrared observational data, including data from the Infrared Space Observatory. Comparing the results of detailed radiative transfer model calculations with observations, we explore the changes of the rele…
An X-ray review of MS 1054-0321: Hot or not?
Braito, V.; Tran, K. -V.; Della Ceca, R. +3 more
XMM-Newton observations are presented for the z=0.83 cluster of galaxies MS 1054-0321, the highest redshift cluster in the Einstein Extended Medium Sensitivity Survey (EMSS). The temperature inferred by the XMM-Newton data, T=7.2+0.7-0.6 keV, is much lower than the temperature previously reported from ASCA data, T=12.3+3…
Polycyclic Aromatic Hydrocarbons and Crystalline Silicates in the Bipolar Post-Asymptotic Giant Branch Star IRAS 16279-4757
Waters, L. B. F. M.; Hony, S.; Zijlstra, A. A. +7 more
IRAS 16279-4757 belongs to a group of post-asymptotic giant branch (post-AGB) stars showing both polycyclic aromatic hydrocarbon (PAH) bands and crystalline silicates. We present mid-infrared images that resolve the object for the first time. The morphology is similar to that of the ``Red Rectangle'' (HD 44179), the prototype object with PAHs and …
Are Giant Planets Forming around HR 4796A?
Kamp, I.; Chen, C. H.
We have obtained Far Ultraviolet Spectroscopic Explorer and Hubble Space Telescope STIS spectra of HR 4796A, a nearby 8 Myr old main-sequence star that possesses a dusty circumstellar disk whose inclination has been constrained from high-resolution near-infrared observations to be ~17° from edge-on. We searched for circumstellar absorption in the …
The influence of density stratification and multiple nonlinearities on solar torsional oscillations
Covas, E.; Moss, D.; Tavakol, R.
Analyses of recent helioseismic data have produced ample evidence for substantial dynamical variation of the differential rotation within the solar convection zone. Given the inevitable difficulties in resolving the precise nature of variations in deeper layers, much effort has recently gone into determining theoretically the expected modes of beh…
Carina's defiant Finger: HST observations of a photoevaporating globule in NGC 3372*
Walborn, Nolan R.; Smith, Nathan; Barbá, Rodolfo H.
We present Hubble Space Telescope Wide Field Planetary Camera 2 images of a prominent externally ionized molecular globule in the Carina Nebula (NGC 3372), supplemented with ground-based infrared images and visual-wavelength spectra. This molecular globule has a shape resembling a human hand, with an extended finger that points toward its likely s…
Temperature map computation for X-ray clusters of galaxies
Bijaoui, A.; Bourdin, H.; Slezak, E. +2 more
Recent numerical simulations have shown that the variations of the gas temperature in clusters of galaxies are indicative of the dynamical state of these clusters. Maps of the temperature variation show complex structures with different shapes at different spatial scales, such as hot compression regions, filaments, cooling flows, or large-scale te…
Titan's surface and rotation: new results from Voyager 1 images
McEwen, Alfred; Lorenz, Ralph D.; Richardson, James
We present an analysis of images of Saturn's moon Titan, obtained by the Voyager 1 spacecraft on November 8-12, 1980. Orange filter (590-640 nm) images were photometrically corrected and a longitudinal average removed from them, leaving residual images with up to 5% contrast, and dominated by surface reflectivity. The resultant map shows the same …