Search Publications
An Analysis of the Shapes of Interstellar Extinction Curves. V. The IR-through-UV Curve Morphology
Fitzpatrick, E. L.; Massa, D.
We study the IR-through-UV interstellar extinction curves towards 328 Galactic B and late-O stars. We use a new technique which employs stellar atmosphere models in lieu of unreddened "standard" stars. This technique is capable of virtually eliminating spectral mismatch errors in the curves. It also allows a quantitative assessment of the errors a…
Warm Gas in the Inner Disks around Young Intermediate-Mass Stars
Simon, Theodore; Najita, Joan R.; Rettig, Terrence W. +1 more
The characterization of gas in the inner disks around young stars is of particular interest because of its connection to planet formation. In order to study the gas in inner disks, we have obtained high-resolution K- and M-band spectroscopy of 14 intermediate-mass young stars. In sources that have optically thick inner disks, i.e., E(K-L)>1, ou…
Hubble Space Telescope Parallaxes of AM CVn Stars and Astrophysical Consequences
Groot, P. J.; McArthur, B. E.; Benedict, G. F. +5 more
We present absolute parallaxes and relative proper motions for five AM CVn stars, which we obtained using the Fine Guidance Sensors on board the Hubble Space Telescope. Our parallax measurements translate into distances dAMCVn=606+135-93 pc, dHPLib=197+14-12 pc, dCRBoo=33…
The SSS Phase of RS Ophiuchi Observed with Chandra and XMM-Newton. I. Data and Preliminary Modeling
Ness, J. -U.; Gehrz, R. D.; Gonzalez-Riestra, R. +13 more
The phase of supersoft source (SSS) emission of the sixth recorded outburst of the recurrent nova RS Oph was observed on days 39.7 and 66.9 after outburst with Chandra and on day 54.0 with XMM-Newton. A ~35 s period on day 54.0 originates from the SSS emission and not from the shock. We discuss the bound-free absorption by neutral elements in the …
The Disk and Environment of a Young Vega Analog: HD 169142
Ménard, F.; Quirrenbach, A.; Hamaguchi, K. +15 more
We trace the disk of HD 169142 (A8 Ve) from 0.57" to 1.4" (~80-200 AU projected distance) in 1.1 µm scattered light with HST NICMOS coronagraphy. The azimuthally symmetric disk has a peak azimuthally medianed surface brightness (SB) of ~5 mJy arcsec-2 at 0.57" from the star, and drops ~r-3. This radial SB profile is con…
Detailed Far-Ultraviolet to Optical Analysis of Four [WR] Stars
Pereira, C. B.; Hillier, D. J.; Marcolino, W. L. F. +1 more
We present far-UV to optical analyses of four hydrogen-deficient central stars of planetary nebulae: BD +30 3639, NGC 40, NGC 5315, and NGC 6905. Using the radiative transfer code CMFGEN, we determined new physical parameters and chemical abundances for these stars. The results were analyzed in the context of the [WR]-->PG 1159 evolution via th…
Two SMC Symbiotic Stars Undergoing Steady Hydrogen Burning
Zezas, A.; Munari, U.; Orio, M. +2 more
Two symbiotic stars in the Small Magellanic Cloud (SMC), Lin 358 and SMC 3, have been supersoft X-ray sources (SSSs) for more than 10 years. We fit atmospheric and nebular models to their X-ray, optical, and UV spectra obtained at different epochs. The X-ray spectra are extremely soft and appear to be emitted by the white dwarf atmosphere, not by …
Early Ultraviolet, Optical, and X-Ray Observations of the Type IIP SN 2005cs in M51 with Swift
Modjaz, Maryam; Kirshner, Robert P.; Dewangan, Gulab C. +14 more
We report early photospheric-phase observations of the Type IIP supernova (SN) 2005cs obtained by the Swift ultraviolet-optical and X-ray telescopes. Observations started within 2 days of discovery and continued on a regular basis for 3 weeks. During this time the V-band magnitude remained essentially constant, while the UV was initially bright, b…
Color, Rotation, Age, and Chromospheric Activity Correlations in Late-Type Main-Sequence Stars
Cassatella, Angelo; Cardini, Daniela
A study of the rotation-activity-age relationships in a large sample of single late-type main-sequence stars is carried out, based on rotation period data from the literature, on our measurements of the Mg II k line chromospheric flux in IUE high-resolution spectra, and on Hipparcos parallaxes. The analysis of the rotation period data of open clus…
Modeling Spitzer Observations of VV Ser. I. The Circumstellar Disk of a UX Orionis Star
van Dishoeck, Ewine F.; Dullemond, Cornelis P.; Pontoppidan, Klaus M. +5 more
We present mid-infrared Spitzer IRS spectra of the UX Orionis star VV Ser, combined with interferometric and spectroscopic data from the literature covering UV to submillimeter wavelengths. The full set of data are modeled by an axisymmetric Monte Carlo radiative transfer code to test the prediction of Dullemond et al. that disks around UX Orionis…