Search Publications
Hubble Space Telescope Planetary Camera Observations of the Stellar Populations Near the Nucleus of M33
Rich, R. Michael; Mighell, Kenneth J.
We have studied the stellar populations near the nucleus of the nearby spiral galaxy M33 using archival observations of the Hubble Space elescope Planetary Camera in the F555W and F785LP passbands. The I vs (V-I) color-magnitude diagram reveals a young stellar population with a blue main sequence and red supergiants, and stars in a blue loop that …
A VIC Color-Magnitude Diagram of the Globular Cluster NGC 6352 From Hubble Space Telescope Planetary Camera Observations
Da Costa, G. S.; Seitzer, P.; Demarque, P. +5 more
The globular cluster NGC 6352, which on the basis of its Galactic position, radial velocity, and [Fe/H] is a member of the (thick) disk system of globular clusters, has been observed to below the main-sequence turnoff (MSTO) using the Hubble Space Telescope. These observations, which were obtained before the repair mission, were analyzed using the…
An Ultraviolet and Optical Study of Accreting Pre-Main-Sequence Stars: Uxors
Herbst, William; Eaton, Nancy L.
UX Ori stars (UXors) are pre-main-sequence stars of both the Herbig Ae/Be and T Tauri type which show aperiodic eclipse-like minima. Their variations have been attributed to occultations by circumstellar material. We use archival IUE spectra and a catalog of UBVRI photometry to study the variations of five such objects, namely, RY Lup, RY Tau, CO …
HST Observations of the Core of the Globular Cluster NGC 6624
King, Ivan R.; Sosin, Craig
We have used the Faint Object Camera (FOC) on the Hubble Space Telescope (HST) to observe three fields near the center of the post-collapse globular cluster NGC 6624 in B and V. We use individual stellar positions and a maximum-likelihood technique to measure a position for the cluster center. We then transfer this position and the position of the…
Spectroscopic Orbits for Symbiotic Binaries. III. Eclipses of the Hot Component in RW Hydrae
Mikolajewska, Joanna; Kenyon, Scott J.
We analyze optical and ultraviolet spectroscopic observations of the symbiotic star RW Hydrae. This system contains an M2 giant and a hot white dwarf, Th=8O,OOO K, in an eclipsing binary system with an orbital period of 370.2±0.9d. The component masses are Mg≈0.5-2 Msun for the red giant and Mh≈O.3-O.6 M…
Low-Mass Binaries in the Hyades
Reid, I. Neill; Gizis, John
We have used the HST Planetary Camera to search for companions to a sample of low-mass (Mυ > 11.5) members of the Hyades cluster. Our observations, which extend in sensitivity beyond the hydrogen-burning limit, detect 5 companions amongst the 21 targets. One binary system appears to lie 70% beyond the Hyades, so the observed binary f…
An Atlas of Alpha Orionis Obtained with the Goddard High Resolution Spectrograph on the Hubble Space Telescope
Savage, B. D.; Ebbets, D. C.; Carpenter, K. G. +18 more
An atlas of observations of the late-type supergiant a Orionis taken with the Goddard High Resolution Spectrograph in 1992 September is presented. We have included identifications of the major features along with the fully reduced spectrum. The 33 exposures consist of 3 high resolution (R∼80,000) and 30 medium resolution (R ∼20,000∼35,000) observa…
Photospheric, Circumstellar, and Interstellar Features of HE, C, O, and SI in the HST Spectra of Four Hot White Dwarf Stars
Fontaine, G.; Wesemael, F.; Vauclair, G. +11 more
This paper reports on the observations of four hot white dwarf stars with the spectrographs on the Hubble Space Telescope (HST). The higher resolving power and higher signal/noise, in comparison with IUE, reveals a very rich phenomomenology, including photospheric features from heavy elements, circumstellar features, and the first direct detection…
White Dwarf Companions to Hyades F Stars
Bohm-Vitense, Erika
We have studied archival, short-wavelength, low resolution IUE spectra of Hyades F stars in an effort to detect white dwarf companions, which can give us information about the IMF for the Hyades duster Weidemann et al. pointed out that we have not detected the expected number of white dwarfs in the Hyades. They suspected that the missing white dwa…
A Radio-Optical Reference Frame.VIII.CCD Observations from KPNO and CTIO: Internal Calibration and First Results
Zacharias, N.; Winter, L.; de Vegt, C. +1 more
In this pilot investigation, precise optical positions in the FK5 system are presented for a set of 16 compact extragalactic radio sources, which will be part of the future radio-optical reference frame. The 0.9 m KPNO and CTIO telescopes equipped with 2 K CCDs have been used for this project. The astrometric properties of these instruments are in…